[GitHub] romseygeek commented on a change in pull request #581: LUCENE-3041: QueryVisitor

[GitBox <gi...@apache.org>]

romseygeek commented on a change in pull request #581: LUCENE-3041: QueryVisitor
URL: https://github.com/apache/lucene-solr/pull/581#discussion_r259011879
 
 

 ##########
 File path: lucene/core/src/java/org/apache/lucene/search/QueryVisitor.java
 ##########
 @@ -0,0 +1,91 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.lucene.search;
+
+import org.apache.lucene.index.Term;
+
+/**
+ * Interface to allow recursion through a query tree
+ *
+ * @see Query#visit(QueryVisitor)
+ */
+public interface QueryVisitor {
+
+  /**
+   * Called by leaf queries that match on a specific term
+   *
+   * @param term  the term the query will match on
+   */
+  void matchesTerm(Term term);
+
+  /**
+   * Called by leaf queries that do not match on terms
+   * @param query the query
+   */
+  default void visitLeaf(Query query) {}
+
+  /**
+   * Pulls a visitor instance for visiting matching child clauses of a query
+   *
+   * The default implementation returns {@code this}
+   *
+   * @param parent  the query visited
+   */
+  default QueryVisitor getMatchingVisitor(Query parent) {
+    return this;
+  }
+
+  /**
+   * Pulls a visitor instance for visiting matching 'should-match' child clauses of a query
+   *
+   * The default implementation returns {@code this}
+   *
+   * @param parent  the query visited
+   */
+  default QueryVisitor getShouldMatchVisitor(Query parent) {
+    return this;
+  }
+
+  /**
+   * Pulls a visitor instance for visiting matching non-scoring child clauses of a query
+   *
+   * The default implementation returns {@code this}
+   *
+   * @param parent  the query visited
+   */
+  default QueryVisitor getFilteringVisitor(Query parent) {
+    return this;
+  }
+
+  /**
+   * Pulls a visitor instance for visiting matching 'must-not' child clauses of a query
+   *
+   * The default implementation returns {@link #NO_OP}
+   *
+   * @param parent  the query visited
+   */
+  default QueryVisitor getNonMatchingVisitor(Query parent) {
+    return NO_OP;
+  }
+
+  /**
+   * A QueryVisitor implementation that collects no terms
+   */
+  QueryVisitor NO_OP = term -> { };
 
 Review comment:
   I've removed it

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@lucene.apache.org
For additional commands, e-mail: dev-help@lucene.apache.org