[2/3] TAJO-240: Reformat HiveConverter source code to match adopted conventions (jaehwa)

[bl...@apache.org]

http://git-wip-us.apache.org/repos/asf/incubator-tajo/blob/5a257e2d/tajo-core/tajo-core-backend/src/main/java/org/apache/tajo/engine/parser/HiveConverter.java
----------------------------------------------------------------------
diff --git a/tajo-core/tajo-core-backend/src/main/java/org/apache/tajo/engine/parser/HiveConverter.java b/tajo-core/tajo-core-backend/src/main/java/org/apache/tajo/engine/parser/HiveConverter.java
index 135d146..95d5c2d 100644
--- a/tajo-core/tajo-core-backend/src/main/java/org/apache/tajo/engine/parser/HiveConverter.java
+++ b/tajo-core/tajo-core-backend/src/main/java/org/apache/tajo/engine/parser/HiveConverter.java
@@ -8,7 +8,7 @@
  * with the License.  You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
- *                                         29
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -36,1559 +36,1569 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.List;
 
-public class HiveConverter extends HiveParserBaseVisitor<Expr>{
-    private static final Log LOG = LogFactory.getLog(HiveConverter.class.getName());
-    private HiveParser parser;
-
-    public Expr parse(String sql) {
-        HiveLexer lexer = new HiveLexer(new ANTLRNoCaseStringStream(sql));
-        CommonTokenStream tokens = new CommonTokenStream(lexer);
-        parser = new HiveParser(tokens);
-        parser.setBuildParseTree(true);
-
-        HiveParser.StatementContext context;
-        try {
-            context = parser.statement();
-        } catch (SQLParseError e) {
-            throw new SQLSyntaxError(e);
-        }
-
-        return visit(context);
+public class HiveConverter extends HiveParserBaseVisitor<Expr> {
+  private static final Log LOG = LogFactory.getLog(HiveConverter.class.getName());
+  private HiveParser parser;
+
+  public Expr parse(String sql) {
+    HiveLexer lexer = new HiveLexer(new ANTLRNoCaseStringStream(sql));
+    CommonTokenStream tokens = new CommonTokenStream(lexer);
+    parser = new HiveParser(tokens);
+    parser.setBuildParseTree(true);
+
+    HiveParser.StatementContext context;
+    try {
+      context = parser.statement();
+    } catch (SQLParseError e) {
+      throw new SQLSyntaxError(e);
     }
 
-    @Override
-    public Expr visitStatement(HiveParser.StatementContext ctx) {
-        return visitExecStatement(ctx.execStatement());
-    }
+    return visit(context);
+  }
 
-    @Override
-    public Expr visitQueryStatement(HiveParser.QueryStatementContext ctx) {
-        Expr current = null;
+  @Override
+  public Expr visitStatement(HiveParser.StatementContext ctx) {
+    return visitExecStatement(ctx.execStatement());
+  }
 
-        if(ctx.body != null) {
-            current = visitBody(ctx.body(0));
-        }
-
-        if(ctx.regular_body() != null) {
-            current = visitRegular_body(ctx.regular_body());
-        }
+  @Override
+  public Expr visitQueryStatement(HiveParser.QueryStatementContext ctx) {
+    Expr current = null;
 
-        return current;
+    if (ctx.body != null) {
+      current = visitBody(ctx.body(0));
     }
 
-    @Override
-    public Expr visitBody(HiveParser.BodyContext ctx) {
-
-        Expr current = null;
-        Insert insert = null;
-
-        Projection select = null;
-
-        if(ctx.insertClause() != null) {
-            insert = visitInsertClause(ctx.insertClause());
-        }
-
-        if(ctx.selectClause() != null) {
-            select = (Projection)visitSelectClause(ctx.selectClause());
-            if(ctx.selectClause().KW_DISTINCT() != null) {
-                select.setDistinct();;
-            }
-
-        }
-
-        for(int i = 0; i < ctx.getParent().getChildCount(); i++) {
-            if(ctx.getParent().getChild(i) instanceof HiveParser.FromClauseContext)  {
-                HiveParser.FromClauseContext fromClauseContext = (HiveParser.FromClauseContext) ctx.getParent().getChild(i);
-                Expr from = visitFromClause(fromClauseContext);
-                current = from;
-            }
-        }
-
-        if(ctx.whereClause() != null) {
-            Selection where = new Selection(visitWhereClause(ctx.whereClause()));
-            where.setChild(current);
-            current = where;
-        }
-
-        if(ctx.groupByClause() != null) {
-            Aggregation aggregation = visitGroupByClause(ctx.groupByClause());
-            aggregation.setChild(current);
-            current = aggregation;
-
-            if(ctx.havingClause() != null) {
-                Expr havingCondition = visitHavingClause(ctx.havingClause());
-                Having having = new Having(havingCondition);
-                having.setChild(current);
-                current = having;
-            }
-        }
-
-        if(ctx.orderByClause() != null) {
-            Sort sort = visitOrderByClause(ctx.orderByClause());
-            sort.setChild(current);
-            current = sort;
-        }
-
-        if(ctx.clusterByClause() != null) {
-            visitClusterByClause(ctx.clusterByClause());
-        }
-
-        if(ctx.distributeByClause() != null) {
-            visitDistributeByClause(ctx.distributeByClause());
-        }
-
-        if(ctx.sortByClause() != null) {
-            Sort sort = visitSortByClause(ctx.sortByClause());
-            sort.setChild(current);
-            current = sort;
-        }
-
-        if(ctx.window_clause() != null) {
-            Expr window = visitWindow_clause(ctx.window_clause());
-        }
-
-        if(ctx.limitClause() != null) {
-            Limit limit = visitLimitClause(ctx.limitClause());
-            limit.setChild(current);
-            current = limit;
-        }
-
-        Projection projection = new Projection();
-        projection.setTargets(select.getTargets());
+    if (ctx.regular_body() != null) {
+      current = visitRegular_body(ctx.regular_body());
+    }
 
-        if(current != null)
-            projection.setChild(current);
+    return current;
+  }
 
-        if(select.isAllProjected())
-            projection.setAll();
+  @Override
+  public Expr visitBody(HiveParser.BodyContext ctx) {
 
-        if(select.isDistinct())
-            projection.setDistinct();
+    Expr current = null;
+    Insert insert = null;
 
+    Projection select = null;
 
-        if(insert != null) {
-            insert.setSubQuery(projection);
-            current = insert;
-        } else {
-            current = projection;
-        }
-
-        return current;
+    if (ctx.insertClause() != null) {
+      insert = visitInsertClause(ctx.insertClause());
     }
 
-    @Override
-    public Expr visitRegular_body(HiveParser.Regular_bodyContext ctx) {
-        Expr current = null;
-        Insert insert = null;
+    if (ctx.selectClause() != null) {
+      select = (Projection) visitSelectClause(ctx.selectClause());
+      if (ctx.selectClause().KW_DISTINCT() != null) {
+        select.setDistinct();
+        ;
+      }
 
-        if(ctx.selectStatement() != null) {
-            current = visitSelectStatement(ctx.selectStatement());
-        } else {
-            Projection select = null;
+    }
 
-            if(ctx.insertClause() != null) {
-                insert = visitInsertClause(ctx.insertClause());
-            }
+    for (int i = 0; i < ctx.getParent().getChildCount(); i++) {
+      if (ctx.getParent().getChild(i) instanceof HiveParser.FromClauseContext) {
+        HiveParser.FromClauseContext fromClauseContext = (HiveParser.FromClauseContext) ctx.getParent().getChild(i);
+        Expr from = visitFromClause(fromClauseContext);
+        current = from;
+      }
+    }
 
-            if(ctx.selectClause() != null) {
-                select = (Projection)visitSelectClause(ctx.selectClause());
-                if(ctx.selectClause().KW_DISTINCT() != null) {
-                    select.setDistinct();;
-                }
+    if (ctx.whereClause() != null) {
+      Selection where = new Selection(visitWhereClause(ctx.whereClause()));
+      where.setChild(current);
+      current = where;
+    }
 
-            }
+    if (ctx.groupByClause() != null) {
+      Aggregation aggregation = visitGroupByClause(ctx.groupByClause());
+      aggregation.setChild(current);
+      current = aggregation;
+
+      if (ctx.havingClause() != null) {
+        Expr havingCondition = visitHavingClause(ctx.havingClause());
+        Having having = new Having(havingCondition);
+        having.setChild(current);
+        current = having;
+      }
+    }
 
-            if(ctx.fromClause() != null) {
-                Expr from = visitFromClause(ctx.fromClause());
-                current = from;
-            }
+    if (ctx.orderByClause() != null) {
+      Sort sort = visitOrderByClause(ctx.orderByClause());
+      sort.setChild(current);
+      current = sort;
+    }
 
-            if(ctx.whereClause() != null) {
-                Selection where = new Selection(visitWhereClause(ctx.whereClause()));
-                where.setChild(current);
-                current = where;
-            }
+    if (ctx.clusterByClause() != null) {
+      visitClusterByClause(ctx.clusterByClause());
+    }
 
-            if(ctx.groupByClause() != null) {
-                Aggregation aggregation = visitGroupByClause(ctx.groupByClause());
-                aggregation.setChild(current);
-                current = aggregation;
-
-                if(ctx.havingClause() != null) {
-                  Expr havingCondition = visitHavingClause(ctx.havingClause());
-                  Having having = new Having(havingCondition);
-                  having.setChild(current);
-                  current = having;
-                }
-            }
+    if (ctx.distributeByClause() != null) {
+      visitDistributeByClause(ctx.distributeByClause());
+    }
 
-            if(ctx.orderByClause() != null) {
-                Sort sort = visitOrderByClause(ctx.orderByClause());
-                sort.setChild(current);
-                current = sort;
-            }
+    if (ctx.sortByClause() != null) {
+      Sort sort = visitSortByClause(ctx.sortByClause());
+      sort.setChild(current);
+      current = sort;
+    }
 
-            if(ctx.clusterByClause() != null) {
-                visitClusterByClause(ctx.clusterByClause());
-            }
+    if (ctx.window_clause() != null) {
+      Expr window = visitWindow_clause(ctx.window_clause());
+    }
 
-            if(ctx.distributeByClause() != null) {
-                visitDistributeByClause(ctx.distributeByClause());
-            }
+    if (ctx.limitClause() != null) {
+      Limit limit = visitLimitClause(ctx.limitClause());
+      limit.setChild(current);
+      current = limit;
+    }
 
-            if(ctx.sortByClause() != null) {
-                Sort sort = visitSortByClause(ctx.sortByClause());
-                sort.setChild(current);
-                current = sort;
-            }
+    Projection projection = new Projection();
+    projection.setTargets(select.getTargets());
 
-            if(ctx.window_clause() != null) {
-                Expr window = visitWindow_clause(ctx.window_clause());
-            }
+    if (current != null)
+      projection.setChild(current);
 
-            if(ctx.limitClause() != null) {
-                Limit limit = visitLimitClause(ctx.limitClause());
-                limit.setChild(current);
-                current = limit;
-            }
+    if (select.isAllProjected())
+      projection.setAll();
 
-            Projection projection = new Projection();
-            projection.setTargets(select.getTargets());
+    if (select.isDistinct())
+      projection.setDistinct();
 
-            if(current != null)
-                projection.setChild(current);
 
-            if(select.isAllProjected())
-                projection.setAll();
+    if (insert != null) {
+      insert.setSubQuery(projection);
+      current = insert;
+    } else {
+      current = projection;
+    }
 
-            if(select.isDistinct())
-                projection.setDistinct();
+    return current;
+  }
 
-            if(insert != null) {
-                insert.setSubQuery(projection);
-                current = insert;
-            } else {
-                current = projection;
-            }
+  @Override
+  public Expr visitRegular_body(HiveParser.Regular_bodyContext ctx) {
+    Expr current = null;
+    Insert insert = null;
 
+    if (ctx.selectStatement() != null) {
+      current = visitSelectStatement(ctx.selectStatement());
+    } else {
+      Projection select = null;
 
-        }
-        return current;
-    }
+      if (ctx.insertClause() != null) {
+        insert = visitInsertClause(ctx.insertClause());
+      }
 
-    /**
-     * This method implemented for parsing union all clause.
-     *
-     * @param ctx
-     * @return
-     */
-    @Override
-    public Expr visitQueryStatementExpression(HiveParser.QueryStatementExpressionContext ctx) {
-        Expr left = null, right = null, current = null;
-        if(ctx.queryStatement() != null) {
-            if(ctx.queryStatement().size() == 1)
-                return visitQueryStatement(ctx.queryStatement(0));
-
-            for(int i = 0; i < ctx.queryStatement().size(); i++) {
-                if(i == 0)
-                    current = visitQueryStatement(ctx.queryStatement(i));
-                else
-                    left = current;
-
-                if(i > 0) {
-                    right = visitQueryStatement(ctx.queryStatement(i));
-                    current = new SetOperation(OpType.Union, left, right, false);
-                }
-            }
+      if (ctx.selectClause() != null) {
+        select = (Projection) visitSelectClause(ctx.selectClause());
+        if (ctx.selectClause().KW_DISTINCT() != null) {
+          select.setDistinct();
+          ;
         }
-        return current;
-    }
 
-    @Override
-    public Expr visitSelectStatement(HiveParser.SelectStatementContext ctx) {
-        Expr current = null;
-
-        Projection select = (Projection)visitSelectClause(ctx.selectClause());
-
-        if(ctx.selectClause().KW_DISTINCT() != null) {
-            select.setDistinct();;
-        }
+      }
 
+      if (ctx.fromClause() != null) {
         Expr from = visitFromClause(ctx.fromClause());
         current = from;
+      }
+
+      if (ctx.whereClause() != null) {
+        Selection where = new Selection(visitWhereClause(ctx.whereClause()));
+        where.setChild(current);
+        current = where;
+      }
+
+      if (ctx.groupByClause() != null) {
+        Aggregation aggregation = visitGroupByClause(ctx.groupByClause());
+        aggregation.setChild(current);
+        current = aggregation;
+
+        if (ctx.havingClause() != null) {
+          Expr havingCondition = visitHavingClause(ctx.havingClause());
+          Having having = new Having(havingCondition);
+          having.setChild(current);
+          current = having;
+        }
+      }
+
+      if (ctx.orderByClause() != null) {
+        Sort sort = visitOrderByClause(ctx.orderByClause());
+        sort.setChild(current);
+        current = sort;
+      }
+
+      if (ctx.clusterByClause() != null) {
+        visitClusterByClause(ctx.clusterByClause());
+      }
+
+      if (ctx.distributeByClause() != null) {
+        visitDistributeByClause(ctx.distributeByClause());
+      }
+
+      if (ctx.sortByClause() != null) {
+        Sort sort = visitSortByClause(ctx.sortByClause());
+        sort.setChild(current);
+        current = sort;
+      }
+
+      if (ctx.window_clause() != null) {
+        Expr window = visitWindow_clause(ctx.window_clause());
+      }
+
+      if (ctx.limitClause() != null) {
+        Limit limit = visitLimitClause(ctx.limitClause());
+        limit.setChild(current);
+        current = limit;
+      }
+
+      Projection projection = new Projection();
+      projection.setTargets(select.getTargets());
+
+      if (current != null)
+        projection.setChild(current);
+
+      if (select.isAllProjected())
+        projection.setAll();
+
+      if (select.isDistinct())
+        projection.setDistinct();
+
+      if (insert != null) {
+        insert.setSubQuery(projection);
+        current = insert;
+      } else {
+        current = projection;
+      }
 
-        if(ctx.whereClause() != null) {
-            Selection where = new Selection(visitWhereClause(ctx.whereClause()));
-            where.setChild(current);
-            current = where;
-        }
-
-        if(ctx.groupByClause() != null) {
-            Aggregation aggregation = visitGroupByClause(ctx.groupByClause());
-            aggregation.setChild(current);
-            current = aggregation;
-
-            if(ctx.havingClause() != null) {
-              Expr havingCondition = visitHavingClause(ctx.havingClause());
-              Having having = new Having(havingCondition);
-              having.setChild(current);
-              current = having;
-            }
-        }
 
-        if(ctx.orderByClause() != null) {
-            Sort sort = visitOrderByClause(ctx.orderByClause());
-            sort.setChild(current);
-            current = sort;
-        }
+    }
+    return current;
+  }
+
+  /**
+   * This method implemented for parsing union all clause.
+   *
+   * @param ctx
+   * @return
+   */
+  @Override
+  public Expr visitQueryStatementExpression(HiveParser.QueryStatementExpressionContext ctx) {
+    Expr left = null, right = null, current = null;
+    if (ctx.queryStatement() != null) {
+      if (ctx.queryStatement().size() == 1)
+        return visitQueryStatement(ctx.queryStatement(0));
+
+      for (int i = 0; i < ctx.queryStatement().size(); i++) {
+        if (i == 0)
+          current = visitQueryStatement(ctx.queryStatement(i));
+        else
+          left = current;
+
+        if (i > 0) {
+          right = visitQueryStatement(ctx.queryStatement(i));
+          current = new SetOperation(OpType.Union, left, right, false);
+        }
+      }
+    }
+    return current;
+  }
 
-        if(ctx.clusterByClause() != null) {
-            visitClusterByClause(ctx.clusterByClause());
-        }
+  @Override
+  public Expr visitSelectStatement(HiveParser.SelectStatementContext ctx) {
+    Expr current = null;
 
-        if(ctx.distributeByClause() != null) {
-            visitDistributeByClause(ctx.distributeByClause());
-        }
+    Projection select = (Projection) visitSelectClause(ctx.selectClause());
 
-        if(ctx.sortByClause() != null) {
-            Sort sort = visitSortByClause(ctx.sortByClause());
-            sort.setChild(current);
-            current = sort;
-        }
+    if (ctx.selectClause().KW_DISTINCT() != null) {
+      select.setDistinct();
+      ;
+    }
 
-        if(ctx.window_clause() != null) {
-            Expr window = visitWindow_clause(ctx.window_clause());
-        }
+    Expr from = visitFromClause(ctx.fromClause());
+    current = from;
 
-        if(ctx.limitClause() != null) {
-            Limit limit = visitLimitClause(ctx.limitClause());
-            limit.setChild(current);
-            current = limit;
-        }
+    if (ctx.whereClause() != null) {
+      Selection where = new Selection(visitWhereClause(ctx.whereClause()));
+      where.setChild(current);
+      current = where;
+    }
 
-        Projection projection = new Projection();
-        projection.setTargets(select.getTargets());
+    if (ctx.groupByClause() != null) {
+      Aggregation aggregation = visitGroupByClause(ctx.groupByClause());
+      aggregation.setChild(current);
+      current = aggregation;
+
+      if (ctx.havingClause() != null) {
+        Expr havingCondition = visitHavingClause(ctx.havingClause());
+        Having having = new Having(havingCondition);
+        having.setChild(current);
+        current = having;
+      }
+    }
 
-        if(current != null)
-            projection.setChild(current);
+    if (ctx.orderByClause() != null) {
+      Sort sort = visitOrderByClause(ctx.orderByClause());
+      sort.setChild(current);
+      current = sort;
+    }
 
-        if(select.isAllProjected())
-            projection.setAll();
+    if (ctx.clusterByClause() != null) {
+      visitClusterByClause(ctx.clusterByClause());
+    }
 
-        if(select.isDistinct())
-            projection.setDistinct();
+    if (ctx.distributeByClause() != null) {
+      visitDistributeByClause(ctx.distributeByClause());
+    }
 
-        current = projection;
+    if (ctx.sortByClause() != null) {
+      Sort sort = visitSortByClause(ctx.sortByClause());
+      sort.setChild(current);
+      current = sort;
+    }
 
-        return current;
+    if (ctx.window_clause() != null) {
+      Expr window = visitWindow_clause(ctx.window_clause());
     }
 
-    @Override
-    public Expr visitFromClause(HiveParser.FromClauseContext ctx) {
-        return visitJoinSource(ctx.joinSource());
+    if (ctx.limitClause() != null) {
+      Limit limit = visitLimitClause(ctx.limitClause());
+      limit.setChild(current);
+      current = limit;
     }
 
-    @Override
-    public Expr visitJoinSource(HiveParser.JoinSourceContext ctx) {
-        Expr[] relations = null;
-        RelationList relationList = null;
+    Projection projection = new Projection();
+    projection.setTargets(select.getTargets());
+
+    if (current != null)
+      projection.setChild(current);
 
-        if(ctx.fromSource() != null) {
-            int fromCount = ctx.fromSource().size();
-            int uniqueJoinCount = ctx.uniqueJoinSource().size();
+    if (select.isAllProjected())
+      projection.setAll();
 
-            relations = new Expr[1];
+    if (select.isDistinct())
+      projection.setDistinct();
 
-            Join current = null, parent = null;
-            JoinType type = null;
-            Expr left = null, right = null, condition = null;
+    current = projection;
 
+    return current;
+  }
 
-            if(fromCount == 1) {
-                relations[0] = visitFromSource(ctx.fromSource(0));
-            } else {
-                left = visitFromSource((HiveParser.FromSourceContext)ctx.getChild(0));
+  @Override
+  public Expr visitFromClause(HiveParser.FromClauseContext ctx) {
+    return visitJoinSource(ctx.joinSource());
+  }
 
-                for(int i = 1; i < ctx.getChildCount(); i++) {
-                    type = null;
-                    right = null;
-                    condition = null;
+  @Override
+  public Expr visitJoinSource(HiveParser.JoinSourceContext ctx) {
+    Expr[] relations = null;
+    RelationList relationList = null;
 
-                    if(ctx.getChild(i) instanceof HiveParser.JoinTokenContext) {
-                        type = getJoinType((HiveParser.JoinTokenContext)ctx.getChild(i));
-                        if(i > 1)
-                            left = parent;
+    if (ctx.fromSource() != null) {
+      int fromCount = ctx.fromSource().size();
+      int uniqueJoinCount = ctx.uniqueJoinSource().size();
 
-                        if(i + 1 < ctx.getChildCount() && ctx.getChild(i+1) instanceof HiveParser.FromSourceContext) {
-                            right = visitFromSource((HiveParser.FromSourceContext)ctx.getChild(i+1));
-                        }
+      relations = new Expr[1];
 
-                        if(i + 3 < ctx.getChildCount() && ctx.getChild(i+3) instanceof HiveParser.ExpressionContext) {
-                            condition = visitExpression((HiveParser.ExpressionContext)ctx.getChild(i+3));
-                        }
+      Join current = null, parent = null;
+      JoinType type = null;
+      Expr left = null, right = null, condition = null;
 
-                        if(type != null) {
-                            current = new Join(type);
-                            current.setLeft(left);
-                            current.setRight(right);
 
-                            if(condition != null)
-                                current.setQual(condition);
+      if (fromCount == 1) {
+        relations[0] = visitFromSource(ctx.fromSource(0));
+      } else {
+        left = visitFromSource((HiveParser.FromSourceContext) ctx.getChild(0));
 
-                            parent = current;
-                        }
-                    }
+        for (int i = 1; i < ctx.getChildCount(); i++) {
+          type = null;
+          right = null;
+          condition = null;
 
-                }
-                relations[0] = current;
+          if (ctx.getChild(i) instanceof HiveParser.JoinTokenContext) {
+            type = getJoinType((HiveParser.JoinTokenContext) ctx.getChild(i));
+            if (i > 1)
+              left = parent;
+
+            if (i + 1 < ctx.getChildCount() && ctx.getChild(i + 1) instanceof HiveParser.FromSourceContext) {
+              right = visitFromSource((HiveParser.FromSourceContext) ctx.getChild(i + 1));
             }
 
-            //TODO: implement unique join.
-            relationList = new RelationList(relations);
-        }
+            if (i + 3 < ctx.getChildCount() && ctx.getChild(i + 3) instanceof HiveParser.ExpressionContext) {
+              condition = visitExpression((HiveParser.ExpressionContext) ctx.getChild(i + 3));
+            }
 
-        return relationList;
-    }
+            if (type != null) {
+              current = new Join(type);
+              current.setLeft(left);
+              current.setRight(right);
 
-    public JoinType getJoinType(HiveParser.JoinTokenContext context) {
-        JoinType type = JoinType.INNER;
+              if (condition != null)
+                current.setQual(condition);
 
-        if(context.KW_INNER() != null) {
-            type = JoinType.INNER;
-        }
+              parent = current;
+            }
+          }
 
-        if(context.KW_LEFT() != null && context.KW_OUTER() != null) {
-            type = JoinType.LEFT_OUTER;
         }
+        relations[0] = current;
+      }
 
-        if(context.KW_RIGHT() != null && context.KW_OUTER() != null) {
-            type = JoinType.RIGHT_OUTER;
-        }
+      //TODO: implement unique join.
+      relationList = new RelationList(relations);
+    }
 
-        if(context.KW_CROSS() != null) {
-            type = JoinType.CROSS;
-        }
+    return relationList;
+  }
 
-        if(context.KW_FULL() != null) {
-            type = JoinType.FULL_OUTER;
-        }
+  public JoinType getJoinType(HiveParser.JoinTokenContext context) {
+    JoinType type = JoinType.INNER;
 
-        if(context.KW_SEMI() != null) {
-            type = null;
-        }
-        return type;
+    if (context.KW_INNER() != null) {
+      type = JoinType.INNER;
     }
 
-    @Override
-    public Expr visitFromSource(HiveParser.FromSourceContext ctx) {
-        Expr current = null;
+    if (context.KW_LEFT() != null && context.KW_OUTER() != null) {
+      type = JoinType.LEFT_OUTER;
+    }
 
-        if(ctx.Identifier() != null && ctx.LPAREN() != null) {
-            current = new LiteralValue(ctx.Identifier().getText(), LiteralValue.LiteralType.String);
-        }
+    if (context.KW_RIGHT() != null && context.KW_OUTER() != null) {
+      type = JoinType.RIGHT_OUTER;
+    }
 
-        if(ctx.tableSource() != null) {
-            current = visitTableSource(ctx.tableSource());
-        }
+    if (context.KW_CROSS() != null) {
+      type = JoinType.CROSS;
+    }
 
-        if(ctx.subQuerySource() != null) {
-            current = visitSubQuerySource(ctx.subQuerySource());
+    if (context.KW_FULL() != null) {
+      type = JoinType.FULL_OUTER;
+    }
 
-            String tableAlias = "";
-            for(int i = 0; i < ctx.subQuerySource().getChildCount(); i++) {
-                if(ctx.subQuerySource().getChild(i) instanceof HiveParser.IdentifierContext) {
-                    tableAlias = ((HiveParser.IdentifierContext)ctx.subQuerySource().getChild(i)).getText();
-                }
-            }
+    if (context.KW_SEMI() != null) {
+      type = null;
+    }
+    return type;
+  }
 
-            TablePrimarySubQuery subQuery = new TablePrimarySubQuery(tableAlias, current);
-            current = subQuery;
-        }
-        // TODO: implement lateralView
+  @Override
+  public Expr visitFromSource(HiveParser.FromSourceContext ctx) {
+    Expr current = null;
 
-        return current;
+    if (ctx.Identifier() != null && ctx.LPAREN() != null) {
+      current = new LiteralValue(ctx.Identifier().getText(), LiteralValue.LiteralType.String);
     }
 
-    @Override
-    public Expr visitSubQuerySource(HiveParser.SubQuerySourceContext ctx) {
-        Expr current = visitQueryStatementExpression(ctx.queryStatementExpression());
-        return current;
+    if (ctx.tableSource() != null) {
+      current = visitTableSource(ctx.tableSource());
     }
 
-    @Override
-    public Expr visitTableSource(HiveParser.TableSourceContext ctx) {
-        String tableName  = "", alias = "";
-
-        if(ctx.tableName() != null)
-            tableName = ctx.tableName().getText();
+    if (ctx.subQuerySource() != null) {
+      current = visitSubQuerySource(ctx.subQuerySource());
 
-        if(ctx.alias != null) {
-            alias = ctx.alias.getText();
-            for(String token : HiveParser.tokenNames) {
-                if(token.replaceAll("'", "").equalsIgnoreCase(alias))
-                    alias = "";
-            }
+      String tableAlias = "";
+      for (int i = 0; i < ctx.subQuerySource().getChildCount(); i++) {
+        if (ctx.subQuerySource().getChild(i) instanceof HiveParser.IdentifierContext) {
+          tableAlias = ((HiveParser.IdentifierContext) ctx.subQuerySource().getChild(i)).getText();
         }
+      }
 
-        Relation relation = new Relation(tableName);
-        if(!alias.equals(""))
-            relation.setAlias(alias);
-
-        return relation;
+      TablePrimarySubQuery subQuery = new TablePrimarySubQuery(tableAlias, current);
+      current = subQuery;
+    }
+    // TODO: implement lateralView
+
+    return current;
+  }
+
+  @Override
+  public Expr visitSubQuerySource(HiveParser.SubQuerySourceContext ctx) {
+    Expr current = visitQueryStatementExpression(ctx.queryStatementExpression());
+    return current;
+  }
+
+  @Override
+  public Expr visitTableSource(HiveParser.TableSourceContext ctx) {
+    String tableName = "", alias = "";
+
+    if (ctx.tableName() != null)
+      tableName = ctx.tableName().getText();
+
+    if (ctx.alias != null) {
+      alias = ctx.alias.getText();
+      for (String token : HiveParser.tokenNames) {
+        if (token.replaceAll("'", "").equalsIgnoreCase(alias))
+          alias = "";
+      }
     }
 
-    @Override
-    public Expr visitSelectList(HiveParser.SelectListContext ctx) {
-        Expr current = null;
-        Projection projection = new Projection();
-        Target[] targets = new Target[ctx.selectItem().size()];
-        for(int i = 0; i < targets.length; i++) {
-            targets[i] = visitSelectItem(ctx.selectItem(i));
-        }
-
-        if(targets.length == 1) {
-            if(targets[0].getExpr().getType().equals(OpType.Column)) {
-                ColumnReferenceExpr columnReferenceExprs = (ColumnReferenceExpr)targets[0].getExpr();
-                if(columnReferenceExprs.getQualifier() == null && columnReferenceExprs.getName().equals("*"))
-                    projection.setAll();;
-            }
-        }
+    Relation relation = new Relation(tableName);
+    if (!alias.equals(""))
+      relation.setAlias(alias);
 
-        if(!projection.isAllProjected())
-            projection.setTargets(targets);
+    return relation;
+  }
 
-        current = projection;
-        return current;
+  @Override
+  public Expr visitSelectList(HiveParser.SelectListContext ctx) {
+    Expr current = null;
+    Projection projection = new Projection();
+    Target[] targets = new Target[ctx.selectItem().size()];
+    for (int i = 0; i < targets.length; i++) {
+      targets[i] = visitSelectItem(ctx.selectItem(i));
     }
 
-    @Override
-    public Target visitSelectItem(HiveParser.SelectItemContext ctx) {
-        ColumnReferenceExpr columnReference;
-        Target target = null;
+    if (targets.length == 1) {
+      if (targets[0].getExpr().getType().equals(OpType.Column)) {
+        ColumnReferenceExpr columnReferenceExprs = (ColumnReferenceExpr) targets[0].getExpr();
+        if (columnReferenceExprs.getQualifier() == null && columnReferenceExprs.getName().equals("*"))
+          projection.setAll();
+        ;
+      }
+    }
 
-        String tableName = "", itemName = "", alias = "";
+    if (!projection.isAllProjected())
+      projection.setTargets(targets);
 
-        String[] selectItem = ctx.getText().split("\\.");
+    current = projection;
+    return current;
+  }
 
-        if(selectItem.length == 2) {
-            tableName = selectItem[0];
-            itemName = selectItem[1];
-        } else if(selectItem.length == 1) {
-            itemName = selectItem[0];
-        } else {
-            itemName = ctx.getText();
-        }
+  @Override
+  public Target visitSelectItem(HiveParser.SelectItemContext ctx) {
+    ColumnReferenceExpr columnReference;
+    Target target = null;
 
-        columnReference = new ColumnReferenceExpr(itemName);
-        if(!tableName.equals(""))
-            columnReference.setQualifier(tableName);
+    String tableName = "", itemName = "", alias = "";
 
-        if(ctx.selectExpression() != null) {
-            if(ctx.selectExpression().expression() != null) {
-                target = new Target(visitSelectExpression(ctx.selectExpression()));
-            } else {
-                target = new Target(columnReference);
-            }
-        }
+    String[] selectItem = ctx.getText().split("\\.");
 
-        if(ctx.identifier().size() > 0) {
-            alias = ctx.identifier(0).getText();
-            if(!alias.equals(itemName))
-                target.setAlias(alias);
-        }
-        return target;
+    if (selectItem.length == 2) {
+      tableName = selectItem[0];
+      itemName = selectItem[1];
+    } else if (selectItem.length == 1) {
+      itemName = selectItem[0];
+    } else {
+      itemName = ctx.getText();
     }
 
-    @Override
-    public Expr visitSelectExpression(HiveParser.SelectExpressionContext ctx) {
-        Expr current = null;
-
-        if(ctx.tableAllColumns() != null) {
-            visitTableAllColumns(ctx.tableAllColumns());
-        } else {
-            if(ctx.expression() != null) {
-                current = visitExpression(ctx.expression());
-            }
-        }
+    columnReference = new ColumnReferenceExpr(itemName);
+    if (!tableName.equals(""))
+      columnReference.setQualifier(tableName);
 
-        return current;
+    if (ctx.selectExpression() != null) {
+      if (ctx.selectExpression().expression() != null) {
+        target = new Target(visitSelectExpression(ctx.selectExpression()));
+      } else {
+        target = new Target(columnReference);
+      }
     }
 
-    @Override
-    public Expr visitExpression(HiveParser.ExpressionContext ctx)  {
-        Expr current = visitPrecedenceOrExpression(ctx.precedenceOrExpression());
-        return current;
+    if (ctx.identifier().size() > 0) {
+      alias = ctx.identifier(0).getText();
+      if (!alias.equals(itemName))
+        target.setAlias(alias);
     }
-
-    @Override
-    public Expr visitPrecedenceOrExpression(HiveParser.PrecedenceOrExpressionContext ctx) {
-        Expr current = null, left = null, right = null;
-
-        for(int i = 0; i < ctx.precedenceAndExpression().size(); i++) {
-            if(i == 0) {
-                left =  visitPrecedenceAndExpression(ctx.precedenceAndExpression(i));
-                current = left;
-            } else {
-                left = current;
-                right =  visitPrecedenceAndExpression(ctx.precedenceAndExpression(i));
-                current = new BinaryOperator(OpType.Or, left, right);
-            }
-
-        }
-        return current;
+    return target;
+  }
+
+  @Override
+  public Expr visitSelectExpression(HiveParser.SelectExpressionContext ctx) {
+    Expr current = null;
+
+    if (ctx.tableAllColumns() != null) {
+      visitTableAllColumns(ctx.tableAllColumns());
+    } else {
+      if (ctx.expression() != null) {
+        current = visitExpression(ctx.expression());
+      }
     }
 
-    /**
-     * This method parse AND expressions at WHERE clause.
-     * And this convert 'x BETWEEN y AND z' expression into 'x >= y AND x <= z' expression
-     * because Tajo doesn't provide 'BETWEEN' expression.
-     *
-     * @param ctx
-     * @return
-     */
-    @Override
-    public Expr visitPrecedenceAndExpression(HiveParser.PrecedenceAndExpressionContext ctx) {
-        Expr current = null, left = null, right = null;
-
-        for(int i = 0; i < ctx.precedenceNotExpression().size(); i++) {
-            Expr min = null, max = null;
-
-            if(ctx.precedenceNotExpression(i).precedenceEqualExpression() != null) {
-                HiveParser.PrecedenceEqualExpressionContext expressionContext = ctx.precedenceNotExpression(i).precedenceEqualExpression();
-                if(expressionContext.KW_BETWEEN() != null) {
-
-                    if(expressionContext.min != null) {
-                        min = visitPrecedenceBitwiseOrExpression(expressionContext.min);
-                    }
+    return current;
+  }
+
+  @Override
+  public Expr visitExpression(HiveParser.ExpressionContext ctx) {
+    Expr current = visitPrecedenceOrExpression(ctx.precedenceOrExpression());
+    return current;
+  }
+
+  @Override
+  public Expr visitPrecedenceOrExpression(HiveParser.PrecedenceOrExpressionContext ctx) {
+    Expr current = null, left = null, right = null;
+
+    for (int i = 0; i < ctx.precedenceAndExpression().size(); i++) {
+      if (i == 0) {
+        left = visitPrecedenceAndExpression(ctx.precedenceAndExpression(i));
+        current = left;
+      } else {
+        left = current;
+        right = visitPrecedenceAndExpression(ctx.precedenceAndExpression(i));
+        current = new BinaryOperator(OpType.Or, left, right);
+      }
 
-                    if(expressionContext.max != null) {
-                        max = visitPrecedenceBitwiseOrExpression(expressionContext.max);
-                    }
-                }
-            }
-
-            if(min != null && max != null) {
-                left = visitPrecedenceNotExpression(ctx.precedenceNotExpression(i));
-                if(left != null) {
-                    if(i == 0) {
-                        BinaryOperator minOperator = new BinaryOperator(OpType.GreaterThanOrEquals, left, min);
-                        BinaryOperator maxOperator = new BinaryOperator(OpType.LessThanOrEquals, left, max);
-                        current = new BinaryOperator(OpType.And, minOperator, maxOperator);
-                    } else {
-                        BinaryOperator minOperator = new BinaryOperator(OpType.GreaterThanOrEquals, left, min);
-                        current = new BinaryOperator(OpType.And, current, minOperator);
-
-                        BinaryOperator maxOperator = new BinaryOperator(OpType.LessThanOrEquals, left, max);
-                        current = new BinaryOperator(OpType.And, current, maxOperator);
-                    }
-                }
-            } else {
-                if(i == 0) {
-                    left = visitPrecedenceNotExpression(ctx.precedenceNotExpression(i));
-                    current = left;
-                } else {
-                    left = current;
-                    right = visitPrecedenceNotExpression(ctx.precedenceNotExpression(i));
-                    current = new BinaryOperator(OpType.And, left, right);
-                }
-            }
-        }
-        return current;
     }
-
-    @Override
-    public Expr visitPrecedenceNotExpression(HiveParser.PrecedenceNotExpressionContext ctx) {
-        HiveParser.PrecedenceEqualExpressionContext expressionContext = ctx.precedenceEqualExpression();
-        Expr current = visitPrecedenceEqualExpression(expressionContext);
-        return current;
-    }
-
-    /**
-     * This method parse operators for equals expressions as follows:
-     *   =, <>, !=, >=, >, <=, <, IN, NOT IN, LIKE, REGEXP, RLIKE
-     *
-     * In this case, this make RuntimeException>
-     *
-     *
-     * @param ctx
-     * @return
-     */
-    @Override
-    public Expr visitPrecedenceEqualExpression(HiveParser.PrecedenceEqualExpressionContext ctx) {
-        Expr current = null, left = null, right = null, min = null, max = null;
-        OpType type = null;
-        boolean isNot = false, isIn = false;
-        for(int i = 0; i < ctx.getChildCount(); i++) {
-            if(ctx.getChild(i) instanceof HiveParser.PrecedenceBitwiseOrExpressionContext) {
-                if(i == 0) {
-                    left = visitPrecedenceBitwiseOrExpression((HiveParser.PrecedenceBitwiseOrExpressionContext)ctx.getChild(i));
-                } else {
-                    right = visitPrecedenceBitwiseOrExpression((HiveParser.PrecedenceBitwiseOrExpressionContext)ctx.getChild(i));
-                }
-            } else if(ctx.getChild(i) instanceof HiveParser.ExpressionsContext) {
-                right = visitExpressions((HiveParser.ExpressionsContext) ctx.getChild(i));
-            } else if(ctx.getChild(i) instanceof  TerminalNodeImpl) {
-                int symbolType = ((TerminalNodeImpl) ctx.getChild(i)).getSymbol().getType();
-                switch (symbolType) {
-                    case  HiveLexer.KW_NOT:
-                        isNot = true;
-                        break;
-                    case HiveLexer.KW_IN:
-                        isIn = true;
-                        break;
-                    default:
-                        break;
-                }
-            } else if(ctx.getChild(i) instanceof  HiveParser.PrecedenceEqualOperatorContext
-                    || ctx.getChild(i) instanceof  HiveParser.PrecedenceEqualNegatableOperatorContext) {
-                String keyword = ctx.getChild(i).getText().toUpperCase();
-
-                if(keyword.equals(">")) {
-                    type = OpType.GreaterThan;
-                } else if(keyword.equals("<=>")) {
-                    throw new RuntimeException("Unexpected operator : <=>");
-                } else if(keyword.equals("=")) {
-                    type = OpType.Equals;
-                } else if(keyword.equals("<=")) {
-                    type = OpType.LessThanOrEquals;
-                } else if(keyword.equals("<")) {
-                    type = OpType.LessThan;
-                } else if(keyword.equals(">=")) {
-                    type = OpType.GreaterThanOrEquals;
-                } else if(keyword.equals("<>")) {
-                    type = OpType.NotEquals;
-                } else if(keyword.equals("!=")) {
-                    type = OpType.NotEquals;
-                } else if(keyword.equals("REGEXP")) {
-                    type = OpType.Regexp;
-                } else if(keyword.equals("RLIKE")) {
-                    type = OpType.Regexp;
-                } else if(keyword.equals("LIKE")) {
-                    type = OpType.LikePredicate;
-                }
-            }
-        }
-
-        if(type != null && right != null) {
-            if(type.equals(OpType.LikePredicate)) {
-                PatternMatchPredicate like = new PatternMatchPredicate(OpType.LikePredicate,
-                    isNot, left, right);
-                current = like;
-            } else if (type.equals(OpType.Regexp)) {
-              PatternMatchPredicate regex = new PatternMatchPredicate(OpType.Regexp, isNot, left, right);
-              current = regex;
-            } else {
-                BinaryOperator binaryOperator = new BinaryOperator(type, left, right);
-                current = binaryOperator;
-            }
-        } else if(isIn) {
-            InPredicate inPredicate = new InPredicate(left, right, isNot);
-            current = inPredicate;
+    return current;
+  }
+
+  /**
+   * This method parse AND expressions at WHERE clause.
+   * And this convert 'x BETWEEN y AND z' expression into 'x >= y AND x <= z' expression
+   * because Tajo doesn't provide 'BETWEEN' expression.
+   *
+   * @param ctx
+   * @return
+   */
+  @Override
+  public Expr visitPrecedenceAndExpression(HiveParser.PrecedenceAndExpressionContext ctx) {
+    Expr current = null, left = null, right = null;
+
+    for (int i = 0; i < ctx.precedenceNotExpression().size(); i++) {
+      Expr min = null, max = null;
+
+      if (ctx.precedenceNotExpression(i).precedenceEqualExpression() != null) {
+        HiveParser.PrecedenceEqualExpressionContext expressionContext = ctx.precedenceNotExpression(i)
+            .precedenceEqualExpression();
+        if (expressionContext.KW_BETWEEN() != null) {
+
+          if (expressionContext.min != null) {
+            min = visitPrecedenceBitwiseOrExpression(expressionContext.min);
+          }
+
+          if (expressionContext.max != null) {
+            max = visitPrecedenceBitwiseOrExpression(expressionContext.max);
+          }
+        }
+      }
+
+      if (min != null && max != null) {
+        left = visitPrecedenceNotExpression(ctx.precedenceNotExpression(i));
+        if (left != null) {
+          if (i == 0) {
+            BinaryOperator minOperator = new BinaryOperator(OpType.GreaterThanOrEquals, left, min);
+            BinaryOperator maxOperator = new BinaryOperator(OpType.LessThanOrEquals, left, max);
+            current = new BinaryOperator(OpType.And, minOperator, maxOperator);
+          } else {
+            BinaryOperator minOperator = new BinaryOperator(OpType.GreaterThanOrEquals, left, min);
+            current = new BinaryOperator(OpType.And, current, minOperator);
+
+            BinaryOperator maxOperator = new BinaryOperator(OpType.LessThanOrEquals, left, max);
+            current = new BinaryOperator(OpType.And, current, maxOperator);
+          }
+        }
+      } else {
+        if (i == 0) {
+          left = visitPrecedenceNotExpression(ctx.precedenceNotExpression(i));
+          current = left;
         } else {
-            current = left;
+          left = current;
+          right = visitPrecedenceNotExpression(ctx.precedenceNotExpression(i));
+          current = new BinaryOperator(OpType.And, left, right);
         }
-
-        return current;
+      }
     }
-
-    @Override
-    public ValueListExpr visitExpressions(HiveParser.ExpressionsContext ctx) {
-        int size = ctx.expression().size();
-        Expr[] exprs = new Expr[size];
-        for(int i = 0; i < size; i++) {
-            exprs[i] = visitExpression(ctx.expression(i));
-        }
-        return new ValueListExpr(exprs);
+    return current;
+  }
+
+  @Override
+  public Expr visitPrecedenceNotExpression(HiveParser.PrecedenceNotExpressionContext ctx) {
+    HiveParser.PrecedenceEqualExpressionContext expressionContext = ctx.precedenceEqualExpression();
+    Expr current = visitPrecedenceEqualExpression(expressionContext);
+    return current;
+  }
+
+  /**
+   * This method parse operators for equals expressions as follows:
+   * =, <>, !=, >=, >, <=, <, IN, NOT IN, LIKE, REGEXP, RLIKE
+   * <p/>
+   * In this case, this make RuntimeException>
+   *
+   * @param ctx
+   * @return
+   */
+  @Override
+  public Expr visitPrecedenceEqualExpression(HiveParser.PrecedenceEqualExpressionContext ctx) {
+    Expr current = null, left = null, right = null, min = null, max = null;
+    OpType type = null;
+    boolean isNot = false, isIn = false;
+    for (int i = 0; i < ctx.getChildCount(); i++) {
+      if (ctx.getChild(i) instanceof HiveParser.PrecedenceBitwiseOrExpressionContext) {
+        if (i == 0) {
+          left = visitPrecedenceBitwiseOrExpression((HiveParser.PrecedenceBitwiseOrExpressionContext) ctx.getChild(i));
+        } else {
+          right = visitPrecedenceBitwiseOrExpression((HiveParser.PrecedenceBitwiseOrExpressionContext) ctx.getChild(i));
+        }
+      } else if (ctx.getChild(i) instanceof HiveParser.ExpressionsContext) {
+        right = visitExpressions((HiveParser.ExpressionsContext) ctx.getChild(i));
+      } else if (ctx.getChild(i) instanceof TerminalNodeImpl) {
+        int symbolType = ((TerminalNodeImpl) ctx.getChild(i)).getSymbol().getType();
+        switch (symbolType) {
+          case HiveLexer.KW_NOT:
+            isNot = true;
+            break;
+          case HiveLexer.KW_IN:
+            isIn = true;
+            break;
+          default:
+            break;
+        }
+      } else if (ctx.getChild(i) instanceof HiveParser.PrecedenceEqualOperatorContext
+          || ctx.getChild(i) instanceof HiveParser.PrecedenceEqualNegatableOperatorContext) {
+        String keyword = ctx.getChild(i).getText().toUpperCase();
+
+        if (keyword.equals(">")) {
+          type = OpType.GreaterThan;
+        } else if (keyword.equals("<=>")) {
+          throw new RuntimeException("Unexpected operator : <=>");
+        } else if (keyword.equals("=")) {
+          type = OpType.Equals;
+        } else if (keyword.equals("<=")) {
+          type = OpType.LessThanOrEquals;
+        } else if (keyword.equals("<")) {
+          type = OpType.LessThan;
+        } else if (keyword.equals(">=")) {
+          type = OpType.GreaterThanOrEquals;
+        } else if (keyword.equals("<>")) {
+          type = OpType.NotEquals;
+        } else if (keyword.equals("!=")) {
+          type = OpType.NotEquals;
+        } else if (keyword.equals("REGEXP")) {
+          type = OpType.Regexp;
+        } else if (keyword.equals("RLIKE")) {
+          type = OpType.Regexp;
+        } else if (keyword.equals("LIKE")) {
+          type = OpType.LikePredicate;
+        }
+      }
     }
 
-    @Override
-    public Expr visitPrecedenceBitwiseOrExpression(HiveParser.PrecedenceBitwiseOrExpressionContext ctx) {
-        int expressionCount = ctx.precedenceAmpersandExpression().size();
-
-        Expr current = null, left = null, right = null, parentLeft, parentRight;
-        OpType type = null, parentType = null;
-
-        for(int i = 0; i < expressionCount; i+=2) {
-            int operatorIndex = (i == 0) ? 0 : i - 1;
-
-            if(ctx.precedenceBitwiseOrOperator(operatorIndex) != null) {
-                type = getPrecedenceBitwiseOrOperator(ctx.precedenceBitwiseOrOperator(operatorIndex));
-            }
+    if (type != null && right != null) {
+      if (type.equals(OpType.LikePredicate)) {
+        PatternMatchPredicate like = new PatternMatchPredicate(OpType.LikePredicate,
+            isNot, left, right);
+        current = like;
+      } else if (type.equals(OpType.Regexp)) {
+        PatternMatchPredicate regex = new PatternMatchPredicate(OpType.Regexp, isNot, left, right);
+        current = regex;
+      } else {
+        BinaryOperator binaryOperator = new BinaryOperator(type, left, right);
+        current = binaryOperator;
+      }
+    } else if (isIn) {
+      InPredicate inPredicate = new InPredicate(left, right, isNot);
+      current = inPredicate;
+    } else {
+      current = left;
+    }
 
-            if(i == 0) {
-                left =  visitPrecedenceAmpersandExpression(ctx.precedenceAmpersandExpression(i));
-                if(ctx.precedenceAmpersandExpression(i+1) != null)
-                    right =  visitPrecedenceAmpersandExpression(ctx.precedenceAmpersandExpression(i+1));
-            } else {
-                parentType = getPrecedenceBitwiseOrOperator((ctx.precedenceBitwiseOrOperator(operatorIndex-1)));
-                parentLeft = visitPrecedenceAmpersandExpression(ctx.precedenceAmpersandExpression(i-2));
-                parentRight = visitPrecedenceAmpersandExpression(ctx.precedenceAmpersandExpression(i-1));
-                left = new BinaryOperator(parentType, parentLeft, parentRight);
-                right =  visitPrecedenceAmpersandExpression(ctx.precedenceAmpersandExpression(i));
-            }
+    return current;
+  }
 
-            if(right != null) {
-                current = new BinaryOperator(type, left, right);
-            } else {
-                current = left;
-            }
-        }
-        return current;
+  @Override
+  public ValueListExpr visitExpressions(HiveParser.ExpressionsContext ctx) {
+    int size = ctx.expression().size();
+    Expr[] exprs = new Expr[size];
+    for (int i = 0; i < size; i++) {
+      exprs[i] = visitExpression(ctx.expression(i));
     }
-
-    public OpType getPrecedenceBitwiseOrOperator(HiveParser.PrecedenceBitwiseOrOperatorContext ctx) {
-        OpType type = null;
-        // TODO: It needs to consider how to support.
-        return type;
+    return new ValueListExpr(exprs);
+  }
+
+  @Override
+  public Expr visitPrecedenceBitwiseOrExpression(HiveParser.PrecedenceBitwiseOrExpressionContext ctx) {
+    int expressionCount = ctx.precedenceAmpersandExpression().size();
+
+    Expr current = null, left = null, right = null, parentLeft, parentRight;
+    OpType type = null, parentType = null;
+
+    for (int i = 0; i < expressionCount; i += 2) {
+      int operatorIndex = (i == 0) ? 0 : i - 1;
+
+      if (ctx.precedenceBitwiseOrOperator(operatorIndex) != null) {
+        type = getPrecedenceBitwiseOrOperator(ctx.precedenceBitwiseOrOperator(operatorIndex));
+      }
+
+      if (i == 0) {
+        left = visitPrecedenceAmpersandExpression(ctx.precedenceAmpersandExpression(i));
+        if (ctx.precedenceAmpersandExpression(i + 1) != null)
+          right = visitPrecedenceAmpersandExpression(ctx.precedenceAmpersandExpression(i + 1));
+      } else {
+        parentType = getPrecedenceBitwiseOrOperator((ctx.precedenceBitwiseOrOperator(operatorIndex - 1)));
+        parentLeft = visitPrecedenceAmpersandExpression(ctx.precedenceAmpersandExpression(i - 2));
+        parentRight = visitPrecedenceAmpersandExpression(ctx.precedenceAmpersandExpression(i - 1));
+        left = new BinaryOperator(parentType, parentLeft, parentRight);
+        right = visitPrecedenceAmpersandExpression(ctx.precedenceAmpersandExpression(i));
+      }
+
+      if (right != null) {
+        current = new BinaryOperator(type, left, right);
+      } else {
+        current = left;
+      }
     }
-
-    @Override
-    public Expr visitPrecedenceAmpersandExpression(HiveParser.PrecedenceAmpersandExpressionContext ctx) {
-        int expressionCount = ctx.precedencePlusExpression().size();
-
-        Expr current = null, left = null, right = null, parentLeft, parentRight;
-        OpType type = null, parentType = null;
-
-        for(int i = 0; i < expressionCount; i+=2) {
-            int operatorIndex = (i == 0) ? 0 : i - 1;
-
-            if(ctx.precedenceAmpersandOperator(operatorIndex) != null) {
-                type = getPrecedenceAmpersandOperator(ctx.precedenceAmpersandOperator(operatorIndex));
-            }
-
-            if(i == 0) {
-                left =  visitPrecedencePlusExpression(ctx.precedencePlusExpression(i));
-                if(ctx.precedencePlusExpression(i+1) != null)
-                    right =  visitPrecedencePlusExpression(ctx.precedencePlusExpression(i+1));
-            } else {
-                parentType = getPrecedenceAmpersandOperator((ctx.precedenceAmpersandOperator(operatorIndex-1)));
-                parentLeft = visitPrecedencePlusExpression(ctx.precedencePlusExpression(i-2));
-                parentRight = visitPrecedencePlusExpression(ctx.precedencePlusExpression(i-1));
-                left = new BinaryOperator(parentType, parentLeft, parentRight);
-                right =  visitPrecedencePlusExpression(ctx.precedencePlusExpression(i));
-            }
-
-            if(right != null) {
-                current = new BinaryOperator(type, left, right);
-            } else {
-                current = left;
-            }
-        }
-        return current;
+    return current;
+  }
+
+  public OpType getPrecedenceBitwiseOrOperator(HiveParser.PrecedenceBitwiseOrOperatorContext ctx) {
+    OpType type = null;
+    // TODO: It needs to consider how to support.
+    return type;
+  }
+
+  @Override
+  public Expr visitPrecedenceAmpersandExpression(HiveParser.PrecedenceAmpersandExpressionContext ctx) {
+    int expressionCount = ctx.precedencePlusExpression().size();
+
+    Expr current = null, left = null, right = null, parentLeft, parentRight;
+    OpType type = null, parentType = null;
+
+    for (int i = 0; i < expressionCount; i += 2) {
+      int operatorIndex = (i == 0) ? 0 : i - 1;
+
+      if (ctx.precedenceAmpersandOperator(operatorIndex) != null) {
+        type = getPrecedenceAmpersandOperator(ctx.precedenceAmpersandOperator(operatorIndex));
+      }
+
+      if (i == 0) {
+        left = visitPrecedencePlusExpression(ctx.precedencePlusExpression(i));
+        if (ctx.precedencePlusExpression(i + 1) != null)
+          right = visitPrecedencePlusExpression(ctx.precedencePlusExpression(i + 1));
+      } else {
+        parentType = getPrecedenceAmpersandOperator((ctx.precedenceAmpersandOperator(operatorIndex - 1)));
+        parentLeft = visitPrecedencePlusExpression(ctx.precedencePlusExpression(i - 2));
+        parentRight = visitPrecedencePlusExpression(ctx.precedencePlusExpression(i - 1));
+        left = new BinaryOperator(parentType, parentLeft, parentRight);
+        right = visitPrecedencePlusExpression(ctx.precedencePlusExpression(i));
+      }
+
+      if (right != null) {
+        current = new BinaryOperator(type, left, right);
+      } else {
+        current = left;
+      }
     }
-
-    public OpType getPrecedenceAmpersandOperator(HiveParser.PrecedenceAmpersandOperatorContext ctx) {
-        OpType type = null;
-        // TODO: It needs to consider how to support.
-        return type;
+    return current;
+  }
+
+  public OpType getPrecedenceAmpersandOperator(HiveParser.PrecedenceAmpersandOperatorContext ctx) {
+    OpType type = null;
+    // TODO: It needs to consider how to support.
+    return type;
+  }
+
+  @Override
+  public Expr visitPrecedencePlusExpression(HiveParser.PrecedencePlusExpressionContext ctx) {
+    int expressionCount = ctx.precedenceStarExpression().size();
+
+    Expr current = null, left = null, right = null, parentLeft, parentRight;
+    OpType type = null, parentType = null;
+
+    for (int i = 0; i < expressionCount; i += 2) {
+      int operatorIndex = (i == 0) ? 0 : i - 1;
+
+      if (ctx.precedencePlusOperator(operatorIndex) != null) {
+        type = getPrecedencePlusOperator(ctx.precedencePlusOperator(operatorIndex));
+      }
+
+      if (i == 0) {
+        left = visitPrecedenceStarExpression(ctx.precedenceStarExpression(i));
+        if (ctx.precedenceStarExpression(i + 1) != null)
+          right = visitPrecedenceStarExpression(ctx.precedenceStarExpression(i + 1));
+      } else {
+        parentType = getPrecedencePlusOperator((ctx.precedencePlusOperator(operatorIndex - 1)));
+        parentLeft = visitPrecedenceStarExpression(ctx.precedenceStarExpression(i - 2));
+        parentRight = visitPrecedenceStarExpression(ctx.precedenceStarExpression(i - 1));
+        left = new BinaryOperator(parentType, parentLeft, parentRight);
+        right = visitPrecedenceStarExpression(ctx.precedenceStarExpression(i));
+      }
+
+      if (right != null) {
+        current = new BinaryOperator(type, left, right);
+      } else {
+        current = left;
+      }
     }
+    return current;
+  }
 
-    @Override
-    public Expr visitPrecedencePlusExpression(HiveParser.PrecedencePlusExpressionContext ctx) {
-        int expressionCount = ctx.precedenceStarExpression().size();
-
-        Expr current = null, left = null, right = null, parentLeft, parentRight;
-        OpType type = null, parentType = null;
+  public OpType getPrecedencePlusOperator(HiveParser.PrecedencePlusOperatorContext ctx) {
+    OpType type = null;
 
-        for(int i = 0; i < expressionCount; i+=2) {
-            int operatorIndex = (i == 0) ? 0 : i - 1;
-
-            if(ctx.precedencePlusOperator(operatorIndex) != null) {
-                type = getPrecedencePlusOperator(ctx.precedencePlusOperator(operatorIndex));
-            }
-
-            if(i == 0) {
-                left =  visitPrecedenceStarExpression(ctx.precedenceStarExpression(i));
-                if(ctx.precedenceStarExpression(i + 1) != null)
-                    right =  visitPrecedenceStarExpression(ctx.precedenceStarExpression(i + 1));
-            } else {
-                parentType = getPrecedencePlusOperator((ctx.precedencePlusOperator(operatorIndex - 1)));
-                parentLeft = visitPrecedenceStarExpression(ctx.precedenceStarExpression(i - 2));
-                parentRight = visitPrecedenceStarExpression(ctx.precedenceStarExpression(i - 1));
-                left = new BinaryOperator(parentType, parentLeft, parentRight);
-                right =  visitPrecedenceStarExpression(ctx.precedenceStarExpression(i));
-            }
-
-            if(right != null) {
-                current = new BinaryOperator(type, left, right);
-            } else {
-                current = left;
-            }
-        }
-        return current;
+    if (ctx.MINUS() != null) {
+      type = OpType.Minus;
+    } else if (ctx.PLUS() != null) {
+      type = OpType.Plus;
     }
 
-    public OpType getPrecedencePlusOperator(HiveParser.PrecedencePlusOperatorContext ctx) {
-        OpType type = null;
-
-        if(ctx.MINUS() != null) {
-            type = OpType.Minus;
-        } else if(ctx.PLUS() != null) {
-            type = OpType.Plus;
-        }
-
-        return type;
+    return type;
+  }
+
+  @Override
+  public Expr visitPrecedenceStarExpression(HiveParser.PrecedenceStarExpressionContext ctx) {
+    int expressionCount = ctx.precedenceBitwiseXorExpression().size();
+
+    Expr current = null, left = null, right = null, parentLeft, parentRight;
+    OpType type = null, parentType = null;
+
+    for (int i = 0; i < expressionCount; i += 2) {
+      int operatorIndex = (i == 0) ? 0 : i - 1;
+
+      if (ctx.precedenceStarOperator(operatorIndex) != null) {
+        type = getPrecedenceStarOperator(ctx.precedenceStarOperator(operatorIndex));
+      }
+
+      if (i == 0) {
+        left = visitPrecedenceBitwiseXorExpression(ctx.precedenceBitwiseXorExpression(i));
+        if (ctx.precedenceBitwiseXorExpression(i + 1) != null)
+          right = visitPrecedenceBitwiseXorExpression(ctx.precedenceBitwiseXorExpression(i + 1));
+      } else {
+        parentType = getPrecedenceStarOperator((ctx.precedenceStarOperator(operatorIndex - 1)));
+        parentLeft = visitPrecedenceBitwiseXorExpression(ctx.precedenceBitwiseXorExpression(i - 2));
+        parentRight = visitPrecedenceBitwiseXorExpression(ctx.precedenceBitwiseXorExpression(i - 1));
+        left = new BinaryOperator(parentType, parentLeft, parentRight);
+        right = visitPrecedenceBitwiseXorExpression(ctx.precedenceBitwiseXorExpression(i));
+      }
+
+      if (right != null) {
+        current = new BinaryOperator(type, left, right);
+      } else {
+        current = left;
+      }
     }
 
-    @Override
-    public Expr visitPrecedenceStarExpression(HiveParser.PrecedenceStarExpressionContext ctx) {
-        int expressionCount = ctx.precedenceBitwiseXorExpression().size();
-
-        Expr current = null, left = null, right = null, parentLeft, parentRight;
-        OpType type = null, parentType = null;
+    return current;
+  }
 
-        for(int i = 0; i < expressionCount; i+=2) {
-            int operatorIndex = (i == 0) ? 0 : i - 1;
+  public OpType getPrecedenceStarOperator(HiveParser.PrecedenceStarOperatorContext ctx) {
+    OpType type = null;
 
-            if(ctx.precedenceStarOperator(operatorIndex) != null) {
-                type = getPrecedenceStarOperator(ctx.precedenceStarOperator(operatorIndex));
-            }
-
-            if(i == 0) {
-                left =  visitPrecedenceBitwiseXorExpression(ctx.precedenceBitwiseXorExpression(i));
-                if(ctx.precedenceBitwiseXorExpression(i + 1) != null)
-                    right =  visitPrecedenceBitwiseXorExpression(ctx.precedenceBitwiseXorExpression(i + 1));
-            } else {
-                parentType = getPrecedenceStarOperator((ctx.precedenceStarOperator(operatorIndex - 1)));
-                parentLeft = visitPrecedenceBitwiseXorExpression(ctx.precedenceBitwiseXorExpression(i - 2));
-                parentRight = visitPrecedenceBitwiseXorExpression(ctx.precedenceBitwiseXorExpression(i - 1));
-                left = new BinaryOperator(parentType, parentLeft, parentRight);
-                right =  visitPrecedenceBitwiseXorExpression(ctx.precedenceBitwiseXorExpression(i));
-            }
-
-            if(right != null) {
-                current = new BinaryOperator(type, left, right);
-            } else {
-                current = left;
-            }
-        }
-
-        return current;
+    if (ctx.DIV() != null) {
+      type = OpType.Divide;
+    } else if (ctx.DIVIDE() != null) {
+      type = OpType.Divide;
+    } else if (ctx.MOD() != null) {
+      type = OpType.Modular;
+    } else if (ctx.STAR() != null) {
+      type = OpType.Multiply;
     }
 
-    public OpType getPrecedenceStarOperator(HiveParser.PrecedenceStarOperatorContext ctx) {
-        OpType type = null;
-
-        if(ctx.DIV() != null) {
-            type = OpType.Divide;
-        } else if(ctx.DIVIDE() != null) {
-            type = OpType.Divide;
-        } else if(ctx.MOD() != null) {
-            type = OpType.Modular;
-        } else if(ctx.STAR() != null) {
-            type = OpType.Multiply;
-        }
-
-        return type;
+    return type;
+  }
+
+  @Override
+  public Expr visitPrecedenceBitwiseXorExpression(HiveParser.PrecedenceBitwiseXorExpressionContext ctx) {
+    int expressionCount = ctx.precedenceUnarySuffixExpression().size();
+
+    Expr current = null, left = null, right = null, parentLeft, parentRight;
+    OpType type = null, parentType = null;
+
+    for (int i = 0; i < expressionCount; i += 2) {
+      int operatorIndex = (i == 0) ? 0 : i - 1;
+
+      if (ctx.precedenceBitwiseXorOperator(operatorIndex) != null) {
+        type = getPrecedenceBitwiseXorOperator(ctx.precedenceBitwiseXorOperator(operatorIndex));
+      }
+
+      if (i == 0) {
+        left = visitPrecedenceUnarySuffixExpression(ctx.precedenceUnarySuffixExpression(i));
+        if (ctx.precedenceUnarySuffixExpression(i + 1) != null)
+          right = visitPrecedenceUnarySuffixExpression(ctx.precedenceUnarySuffixExpression(i + 1));
+      } else {
+        parentType = getPrecedenceBitwiseXorOperator((ctx.precedenceBitwiseXorOperator(operatorIndex - 1)));
+        parentLeft = visitPrecedenceUnarySuffixExpression(ctx.precedenceUnarySuffixExpression(i - 2));
+        parentRight = visitPrecedenceUnarySuffixExpression(ctx.precedenceUnarySuffixExpression(i - 1));
+        left = new BinaryOperator(parentType, parentLeft, parentRight);
+        right = visitPrecedenceUnarySuffixExpression(ctx.precedenceUnarySuffixExpression(i));
+      }
+
+      if (right != null) {
+        current = new BinaryOperator(type, left, right);
+      } else {
+        current = left;
+      }
     }
 
-    @Override
-    public Expr visitPrecedenceBitwiseXorExpression(HiveParser.PrecedenceBitwiseXorExpressionContext ctx) {
-        int expressionCount = ctx.precedenceUnarySuffixExpression().size();
+    return current;
+  }
 
-        Expr current = null, left = null, right = null, parentLeft, parentRight;
-        OpType type = null, parentType = null;
+  public OpType getPrecedenceBitwiseXorOperator(HiveParser.PrecedenceBitwiseXorOperatorContext ctx) {
+    OpType type = null;
+    // TODO: It needs to consider how to support.
 
-        for(int i = 0; i < expressionCount; i+=2) {
-            int operatorIndex = (i == 0) ? 0 : i - 1;
+    return type;
+  }
 
-            if(ctx.precedenceBitwiseXorOperator(operatorIndex) != null) {
-                type = getPrecedenceBitwiseXorOperator(ctx.precedenceBitwiseXorOperator(operatorIndex));
-            }
-
-            if(i == 0) {
-                left =  visitPrecedenceUnarySuffixExpression(ctx.precedenceUnarySuffixExpression(i));
-                if(ctx.precedenceUnarySuffixExpression(i + 1) != null)
-                    right =  visitPrecedenceUnarySuffixExpression(ctx.precedenceUnarySuffixExpression(i + 1));
-            } else {
-                parentType = getPrecedenceBitwiseXorOperator((ctx.precedenceBitwiseXorOperator(operatorIndex - 1)));
-                parentLeft = visitPrecedenceUnarySuffixExpression(ctx.precedenceUnarySuffixExpression(i - 2));
-                parentRight = visitPrecedenceUnarySuffixExpression(ctx.precedenceUnarySuffixExpression(i - 1));
-                left = new BinaryOperator(parentType, parentLeft, parentRight);
-                right =  visitPrecedenceUnarySuffixExpression(ctx.precedenceUnarySuffixExpression(i));
-            }
-
-            if(right != null) {
-                current = new BinaryOperator(type, left, right);
-            } else {
-                current = left;
-            }
-        }
+  @Override
+  public Expr visitPrecedenceUnarySuffixExpression(HiveParser.PrecedenceUnarySuffixExpressionContext ctx) {
+    Expr current = visitPrecedenceUnaryPrefixExpression(ctx.precedenceUnaryPrefixExpression());
 
-        return current;
+    if (ctx.nullCondition() != null) {
+      boolean isNot = ctx.nullCondition().KW_NOT() == null ? false : true;
+      IsNullPredicate isNullPredicate = new IsNullPredicate(isNot, (ColumnReferenceExpr) current);
+      current = isNullPredicate;
     }
 
-    public OpType getPrecedenceBitwiseXorOperator(HiveParser.PrecedenceBitwiseXorOperatorContext ctx) {
-        OpType type = null;
-        // TODO: It needs to consider how to support.
-
-        return type;
+    return current;
+  }
+
+  @Override
+  public Expr visitPrecedenceUnaryPrefixExpression(HiveParser.PrecedenceUnaryPrefixExpressionContext ctx) {
+    Expr current = visitPrecedenceFieldExpression(ctx.precedenceFieldExpression());
+    return current;
+  }
+
+  @Override
+  public Expr visitNullCondition(HiveParser.NullConditionContext ctx) {
+    return new NullValue();
+  }
+
+  @Override
+  public Expr visitPrecedenceFieldExpression(HiveParser.PrecedenceFieldExpressionContext ctx) {
+    Expr current = visitAtomExpression(ctx.atomExpression());
+
+    if (ctx.DOT().size() > 0) {
+      ColumnReferenceExpr column = new ColumnReferenceExpr(ctx.identifier(0).getText());
+      ColumnReferenceExpr table = (ColumnReferenceExpr) current;
+      column.setQualifier(table.getName());
+      current = column;
     }
+    return current;
+  }
 
-    @Override
-    public Expr visitPrecedenceUnarySuffixExpression(HiveParser.PrecedenceUnarySuffixExpressionContext ctx) {
-        Expr current = visitPrecedenceUnaryPrefixExpression(ctx.precedenceUnaryPrefixExpression());
-
-        if(ctx.nullCondition() != null) {
-            boolean isNot = ctx.nullCondition().KW_NOT() == null ? false : true;
-            IsNullPredicate isNullPredicate = new IsNullPredicate(isNot, (ColumnReferenceExpr)current);
-            current = isNullPredicate;
-        }
+  @Override
+  public Expr visitAtomExpression(HiveParser.AtomExpressionContext ctx) {
+    Expr current = null;
 
-        return current;
+    if (ctx.KW_NULL() != null) {
+      current = new NullValue();
     }
-
-    @Override
-    public Expr visitPrecedenceUnaryPrefixExpression(HiveParser.PrecedenceUnaryPrefixExpressionContext ctx)  {
-        Expr current = visitPrecedenceFieldExpression(ctx.precedenceFieldExpression());
-        return current;
+    if (ctx.constant() != null) {
+      current = visitConstant(ctx.constant());
     }
-
-    @Override
-    public Expr visitNullCondition(HiveParser.NullConditionContext ctx)  {
-        return new NullValue();
+    if (ctx.function() != null) {
+      current = visitFunction(ctx.function());
     }
-
-    @Override
-    public Expr visitPrecedenceFieldExpression(HiveParser.PrecedenceFieldExpressionContext ctx)  {
-        Expr current = visitAtomExpression(ctx.atomExpression());
-
-        if(ctx.DOT().size() > 0) {
-            ColumnReferenceExpr column = new ColumnReferenceExpr(ctx.identifier(0).getText());
-            ColumnReferenceExpr table = (ColumnReferenceExpr)current;
-            column.setQualifier(table.getName());
-            current = column;
-        }
-        return current;
+    if (ctx.castExpression() != null) {
+      current = visitCastExpression(ctx.castExpression());
     }
-
-    @Override
-    public Expr visitAtomExpression(HiveParser.AtomExpressionContext ctx) {
-        Expr current = null;
-
-        if(ctx.KW_NULL() != null) {
-            current = new NullValue();
-        }
-        if(ctx.constant() != null) {
-            current = visitConstant(ctx.constant());
-        }
-        if(ctx.function() != null) {
-            current = visitFunction(ctx.function());
-        }
-        if(ctx.castExpression() != null) {
-            current = visitCastExpression(ctx.castExpression());
-        }
-        if(ctx.caseExpression() != null) {
-            current = visitCaseExpression(ctx.caseExpression());
-        }
-        if(ctx.whenExpression() != null) {
-            current = visitWhenExpression(ctx.whenExpression());
-        }
-        if(ctx.tableOrColumn() != null) {
-            current = visitTableOrColumn(ctx.tableOrColumn());
-        } else {
-            if(ctx.LPAREN() != null && ctx.RPAREN() != null) {
-                current = visitExpression(ctx.expression());
-            }
-        }
-
-        return current;
+    if (ctx.caseExpression() != null) {
+      current = visitCaseExpression(ctx.caseExpression());
     }
-
-    @Override
-    public Expr visitTableOrColumn(HiveParser.TableOrColumnContext ctx)  {
-        ColumnReferenceExpr columnReferenceExpr = new ColumnReferenceExpr(ctx.identifier().getText());
-        return  columnReferenceExpr;
+    if (ctx.whenExpression() != null) {
+      current = visitWhenExpression(ctx.whenExpression());
     }
-
-    @Override
-    public Expr visitIdentifier(HiveParser.IdentifierContext ctx)  {
-        Expr current = null;
-
-        if(ctx.nonReserved() != null) {
-            current = new LiteralValue(ctx.nonReserved().getText(), LiteralValue.LiteralType.String);
-        } else {
-            current = new LiteralValue(ctx.Identifier().getText(), LiteralValue.LiteralType.String);
-        }
-
-        return current;
+    if (ctx.tableOrColumn() != null) {
+      current = visitTableOrColumn(ctx.tableOrColumn());
+    } else {
+      if (ctx.LPAREN() != null && ctx.RPAREN() != null) {
+        current = visitExpression(ctx.expression());
+      }
     }
 
-    @Override
-    public LiteralValue visitConstant(HiveParser.ConstantContext ctx) {
-        LiteralValue literalValue = null;
-
-        if(ctx.StringLiteral() != null) {
-            String value = ctx.StringLiteral().getText();
-            String strValue = "";
-            if((value.startsWith("'") && value.endsWith("'")) || value.startsWith("\"") && value.endsWith("\"")) {
-                strValue = value.substring(1, value.length()-1);
-            }  else {
-                strValue = value;
-            }
+    return current;
+  }
 
-            literalValue = new LiteralValue(strValue, LiteralValue.LiteralType.String);
-        } else if(ctx.TinyintLiteral() != null) {
-            literalValue = new LiteralValue(ctx.TinyintLiteral().getSymbol().getText(), LiteralValue.LiteralType.Unsigned_Integer);
-        } else if(ctx.BigintLiteral() != null) {
-            literalValue = new LiteralValue(ctx.BigintLiteral().getSymbol().getText(), LiteralValue.LiteralType.Unsigned_Large_Integer);
-        } else if(ctx.DecimalLiteral() != null) {
-            literalValue = new LiteralValue(ctx.DecimalLiteral().getSymbol().getText(), LiteralValue.LiteralType.Unsigned_Integer);
-        } else if(ctx.Number() != null) {
-            try {
-                float floatValue = NumberUtils.createFloat(ctx.getText());
-                literalValue = new LiteralValue(ctx.Number().getSymbol().getText(), LiteralValue.LiteralType.Unsigned_Float);
-            } catch (NumberFormatException nf) {
-            }
+  @Override
+  public Expr visitTableOrColumn(HiveParser.TableOrColumnContext ctx) {
+    ColumnReferenceExpr columnReferenceExpr = new ColumnReferenceExpr(ctx.identifier().getText());
+    return columnReferenceExpr;
+  }
 
-            // TODO: double type
+  @Override
+  public Expr visitIdentifier(HiveParser.IdentifierContext ctx) {
+    Expr current = null;
 
-            try {
-                BigInteger bigIntegerVallue = NumberUtils.createBigInteger(ctx.getText());
-                literalValue = new LiteralValue(ctx.Number().getSymbol().getText(), LiteralValue.LiteralType.Unsigned_Large_Integer);
-            } catch (NumberFormatException nf) {
-            }
-
-            try {
-                int intValue = NumberUtils.createInteger(ctx.getText());
-                literalValue = new LiteralValue(ctx.Number().getSymbol().getText(), LiteralValue.LiteralType.Unsigned_Integer);
-            } catch (NumberFormatException nf) {
-            }
-
-        } else if(ctx.SmallintLiteral() != null) {
-            literalValue = new LiteralValue(ctx.SmallintLiteral().getSymbol().getText(), LiteralValue.LiteralType.Unsigned_Integer);
-        } else if(ctx.booleanValue() != null) {
-            // TODO: boolean type
-        }
-
-        return literalValue;
+    if (ctx.nonReserved() != null) {
+      current = new LiteralValue(ctx.nonReserved().getText(), LiteralValue.LiteralType.String);
+    } else {
+      current = new LiteralValue(ctx.Identifier().getText(), LiteralValue.LiteralType.String);
     }
 
-    @Override
-    public Expr visitFunction(HiveParser.FunctionContext ctx)  {
-        Expr current = null;
-        String signature = ctx.functionName().getText();
-
-        boolean isDistinct = false;
-        if(ctx.getChild(2) != null) {
-            if(ctx.getChild(2) instanceof TerminalNodeImpl && ctx.getChild(2).getText().equalsIgnoreCase("DISTINCT")) {
-                isDistinct = true;
-            }
-        }
-
-        if(signature.equalsIgnoreCase("MIN")
-                || signature.equalsIgnoreCase("MAX")
-                || signature.equalsIgnoreCase("SUM")
-                || signature.equalsIgnoreCase("AVG")
-                || signature.equalsIgnoreCase("COUNT")
-                ) {
-            if(ctx.selectExpression().size() > 1) {
-                throw new RuntimeException("Exactly expected one argument.");
-            }
+    return current;
+  }
+
+  @Override
+  public LiteralValue visitConstant(HiveParser.ConstantContext ctx) {
+    LiteralValue literalValue = null;
+
+    if (ctx.StringLiteral() != null) {
+      String value = ctx.StringLiteral().getText();
+      String strValue = "";
+      if ((value.startsWith("'") && value.endsWith("'")) || value.startsWith("\"") && value.endsWith("\"")) {
+        strValue = value.substring(1, value.length() - 1);
+      } else {
+        strValue = value;
+      }
+
+      literalValue = new LiteralValue(strValue, LiteralValue.LiteralType.String);
+    } else if (ctx.TinyintLiteral() != null) {
+      literalValue = new LiteralValue(ctx.TinyintLiteral().getSymbol().getText(),
+          LiteralValue.LiteralType.Unsigned_Integer);
+    } else if (ctx.BigintLiteral() != null) {
+      literalValue = new LiteralValue(ctx.BigintLiteral().getSymbol().getText(),
+          LiteralValue.LiteralType.Unsigned_Large_Integer);
+    } else if (ctx.DecimalLiteral() != null) {
+      literalValue = new LiteralValue(ctx.DecimalLiteral().getSymbol().getText(),
+          LiteralValue.LiteralType.Unsigned_Integer);
+    } else if (ctx.Number() != null) {
+      try {
+        float floatValue = NumberUtils.createFloat(ctx.getText());
+        literalValue = new LiteralValue(ctx.Number().getSymbol().getText(), LiteralValue.LiteralType.Unsigned_Float);
+      } catch (NumberFormatException nf) {
+      }
+
+      // TODO: double type
+
+      try {
+        BigInteger bigIntegerVallue = NumberUtils.createBigInteger(ctx.getText());
+        literalValue = new LiteralValue(ctx.Number().getSymbol().getText(),
+            LiteralValue.LiteralType.Unsigned_Large_Integer);
+      } catch (NumberFormatException nf) {
+      }
+
+      try {
+        int intValue = NumberUtils.createInteger(ctx.getText());
+        literalValue = new LiteralValue(ctx.Number().getSymbol().getText(), LiteralValue.LiteralType.Unsigned_Integer);
+      } catch (NumberFormatException nf) {
+      }
+
+    } else if (ctx.SmallintLiteral() != null) {
+      literalValue = new LiteralValue(ctx.SmallintLiteral().getSymbol().getText(),
+          LiteralValue.LiteralType.Unsigned_Integer);
+    } else if (ctx.booleanValue() != null) {
+      // TODO: boolean type
+    }
 
-            if(ctx.selectExpression().size() == 0) {
-                CountRowsFunctionExpr countRowsFunctionExpr = new CountRowsFunctionExpr();
-                current = countRowsFunctionExpr;
-            } else {
-                GeneralSetFunctionExpr setFunctionExpr = new GeneralSetFunctionExpr(signature, isDistinct, visitSelectExpression(ctx.selectExpression(0)));
-                current = setFunctionExpr;
-            }
-        }  else {
-            FunctionExpr functionExpr = new FunctionExpr(signature);
-            Expr[] params = new Expr[ctx.selectExpression().size()];
-            for(int i = 0; i < ctx.selectExpression().size(); i++) {
-                params[i] = visitSelectExpression(ctx.selectExpression(i));
-            }
-            functionExpr.setParams(params);
-            current = functionExpr;
-        }
+    return literalValue;
+  }
 
+  @Override
+  public Expr visitFunction(HiveParser.FunctionContext ctx) {
+    Expr current = null;
+    String signature = ctx.functionName().getText();
 
-        return current;
+    boolean isDistinct = false;
+    if (ctx.getChild(2) != null) {
+      if (ctx.getChild(2) instanceof TerminalNodeImpl && ctx.getChild(2).getText().equalsIgnoreCase("DISTINCT")) {
+        isDistinct = true;
+      }
     }
 
-    /**
-     * This method parse CAST expression.
-     * This returns only expression field without casting type
-     * because Tajo doesn't provide CAST expression.
-     *
-     * @param ctx
-     * @return
-     */
-    @Override
-    public Expr visitCastExpression(HiveParser.CastExpressionContext ctx)  {
-        return visitExpression(ctx.expression());
+    if (signature.equalsIgnoreCase("MIN")
+        || signature.equalsIgnoreCase("MAX")
+        || signature.equalsIgnoreCase("SUM")
+        || signature.equalsIgnoreCase("AVG")
+        || signature.equalsIgnoreCase("COUNT")
+        ) {
+      if (ctx.selectExpression().size() > 1) {
+        throw new RuntimeException("Exactly expected one argument.");
+      }
+
+      if (ctx.selectExpression().size() == 0) {
+        CountRowsFunctionExpr countRowsFunctionExpr = new CountRowsFunctionExpr();
+        current = countRowsFunctionExpr;
+      } else {
+        GeneralSetFunctionExpr setFunctionExpr = new GeneralSetFunctionExpr(signature, isDistinct,
+            visitSelectExpression(ctx.selectExpression(0)));
+        current = setFunctionExpr;
+      }
+    } else {
+      FunctionExpr functionExpr = new FunctionExpr(signature);
+      Expr[] params = new Expr[ctx.selectExpression().size()];
+      for (int i = 0; i < ctx.selectExpression().size(); i++) {
+        params[i] = visitSelectExpression(ctx.selectExpression(i));
+      }
+      functionExpr.setParams(params);
+      current = functionExpr;
     }
 
-    @Override
-    public Expr visitCaseExpression(HiveParser.CaseExpressionContext ctx)  {
-        CaseWhenPredicate caseWhen = new CaseWhenPredicate();
-        Expr condition = null, result = null;
-        for(int i = 1; i < ctx.getChildCount(); i++) {
-            if(ctx.getChild(i) instanceof TerminalNodeImpl) {
-                if(((TerminalNodeImpl) ctx.getChild(i)).getSymbol().getType() == HiveLexer.KW_WHEN) {
-                    condition = null;
-                    result = null;
-
-                    if(ctx.getChild(i+1) instanceof HiveParser.ExpressionContext) {
-                        condition = visitExpression((HiveParser.ExpressionContext)ctx.getChild(i+1));
-                    }
-
-                    if(ctx.getChild(i+3) instanceof HiveParser.ExpressionContext) {
-                        result = visitExpression((HiveParser.ExpressionContext)ctx.getChild(i+3));
-                    }
-
-                    if(condition != null && result != null) {
-                        caseWhen.addWhen(condition, result);
-                    }
-                } else if(((TerminalNodeImpl) ctx.getChild(i)).getSymbol().getType() == HiveLexer.KW_ELSE) {
-                    result = visitExpression((HiveParser.ExpressionContext)ctx.getChild(i+1));
-                    caseWhen.setElseResult(result);
-                }
-            }
-        }
 
-        return caseWhen;
+    return current;
+  }
+
+  /**
+   * This method parse CAST expression.
+   * This returns only expression field without casting type
+   * because Tajo doesn't provide CAST expression.
+   *
+   * @param ctx
+   * @return
+   */
+  @Override
+  public Expr visitCastExpression(HiveParser.CastExpressionContext ctx) {
+    return visitExpression(ctx.expression());
+  }
+
+  @Override
+  public Expr visitCaseExpression(HiveParser.CaseExpressionContext ctx) {
+    CaseWhenPredicate caseWhen = new CaseWhenPredicate();
+    Expr condition = null, result = null;
+    for (int i = 1; i < ctx.getChildCount(); i++) {
+      if (ctx.getChild(i) instanceof TerminalNodeImpl) {
+        if (((TerminalNodeImpl) ctx.getChild(i)).getSymbol().getType() == HiveLexer.KW_WHEN) {
+          condition = null;
+          result = null;
+
+          if (ctx.getChild(i + 1) instanceof HiveParser.ExpressionContext) {
+            condition = visitExpression((HiveParser.ExpressionContext) ctx.getChild(i + 1));
+          }
+
+          if (ctx.getChild(i + 3) instanceof HiveParser.ExpressionContext) {
+            result = visitExpression((HiveParser.ExpressionContext) ctx.getChild(i + 3));
+          }
+
+          if (condition != null && result != null) {
+            caseWhen.addWhen(condition, result);
+          }
+        } else if (((TerminalNodeImpl) ctx.getChild(i)).getSymbol().getType() == HiveLexer.KW_ELSE) {
+          result = visitExpression((HiveParser.ExpressionContext) ctx.getChild(i + 1));
+          caseWhen.setElseResult(result);
+        }
+      }
     }
 
-    @Override
-    public Expr visitWhenExpression(HiveParser.WhenExpressionContext ctx)  {
-        CaseWhenPredicate caseWhen = new CaseWhenPredicate();
-        Expr condition = null, result = null;
-        for(int i = 1; i < ctx.getChildCount(); i++) {
-            if(ctx.getChild(i) instanceof TerminalNodeImpl) {
-                if(((TerminalNodeImpl) ctx.getChild(i)).getSymbol().getType() == HiveLexer.KW_WHEN) {
-                    condition = null;
-                    result = null;
-
-                    if(ctx.getChild(i+1) instanceof HiveParser.ExpressionContext) {
-                        condition = visitExpression((HiveParser.ExpressionContext)ctx.getChild(i+1));
-                    }
-
-                    if(ctx.getChild(i+3) instanceof HiveParser.ExpressionContext) {
-                        result = visitExpression((HiveParser.ExpressionContext)ctx.getChild(i+3));
-                    }
-
-                    if(condition != null && result != null) {
-                        caseWhen.addWhen(condition, result);
-                    }
-                } else if(((TerminalNodeImpl) ctx.getChild(i)).getSymbol().getType() == HiveLexer.KW_ELSE) {
-                    result = visitExpression((HiveParser.ExpressionContext)ctx.getChild(i+1));
-                    caseWhen.setElseResult(result);
-                }
-            }
-        }
-
-        return caseWhen;
+    return caseWhen;
+  }
+
+  @Override
+  public Expr visitWhenExpression(HiveParser.WhenExpressionContext ctx) {
+    CaseWhenPredicate caseWhen = new CaseWhenPredicate();
+    Expr condition = null, result = null;
+    for (int i = 1; i < ctx.getChildCount(); i++) {
+      if (ctx.getChild(i) instanceof TerminalNodeImpl) {
+        if (((TerminalNodeImpl) ctx.getChild(i)).getSymbol().getType() == HiveLexer.KW_WHEN) {
+          condition = null;
+          result = null;
+
+          if (ctx.getChild(i + 1) instanceof HiveParser.ExpressionContext) {
+            condition = visitExpression((HiveParser.ExpressionContext) ctx.getChild(i + 1));
+          }
+
+          if (ctx.getChild(i + 3) instanceof HiveParser.ExpressionContext) {
+            result = visitExpression((HiveParser.ExpressionContext) ctx.getChild(i + 3));
+          }
+
+          if (condition != null && result != null) {
+            caseWhen.addWhen(condition, result);
+          }
+        } else if (((TerminalNodeImpl) ctx.getChild(i)).getSymbol().getType

<TRUNCATED>