[GitHub] [ignite] timoninmaxim commented on a change in pull request #9118: IGNITE-14699 Add IndexQuery API.

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

timoninmaxim commented on a change in pull request #9118:
URL: https://github.com/apache/ignite/pull/9118#discussion_r642647280



##########
File path: modules/core/src/main/java/org/apache/ignite/cache/query/IndexQuery.java
##########
@@ -0,0 +1,263 @@
+/*
+ * 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.ignite.cache.query;
+
+import javax.cache.Cache;
+import org.apache.ignite.internal.cache.query.IndexCondition;
+import org.apache.ignite.internal.cache.query.RangeIndexCondition;
+import org.apache.ignite.internal.util.typedef.internal.A;
+import org.apache.ignite.lang.IgniteExperimental;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Index query runs over internal index structure and returns cache entries for index rows that match specified condition.
+ */
+@IgniteExperimental
+public class IndexQuery<K, V> extends Query<Cache.Entry<K, V>> {
+    /** */
+    private static final long serialVersionUID = 0L;
+
+    /** Object to mark a boundary if {@code null} is specified. */
+    private static final Object NULL = new Null();
+
+    /** Index condition describes index query clause. */
+    private IndexCondition idxCond;
+
+    /** Cache Value class. Describes a table within a cache that runs a query. */
+    private final String valCls;
+
+    /** Optional index name. Find index by fields in condition. */
+    private final @Nullable String idxName;
+
+    /** Optional schema name. User has to specify schema to run query over an index created with SQL. */
+    private final @Nullable String schema;
+
+    /** */
+    private IndexQuery(String valCls, @Nullable String idxName, @Nullable String schema) {
+        this.valCls = valCls;
+        this.idxName = idxName;
+        this.schema = schema;
+    }
+
+    /**
+     * Specify index with cache value class. Ignite checks all indexes to find best match by
+     * {@link #valCls} and {@link IndexCondition#fields()}.
+     */
+    public static <K, V> IndexQuery<K, V> forType(Class<V> valCls) {
+        A.notNull(valCls, "valCls");
+
+        return new IndexQuery<>(valCls.getName(), null, null);
+    }
+
+    /**
+     * Specify index with cache value class and index name.
+     */
+    public static <K, V> IndexQuery<K, V> forIndex(Class<V> valCls, String idxName) {
+        A.notNull(valCls, "valCls");
+
+        return new IndexQuery<>(valCls.getName(), idxName, null);
+    }
+
+    /**
+     * Specify index with cache value class, index name and schema name.
+     * Note that schema is required parameter for indexes created with the "CREATE INDEX" SQL-clause.
+     */
+    public static <K, V> IndexQuery<K, V> forIndex(Class<V> valCls, String idxName, String schema) {
+        A.notNull(valCls, "valCls");
+
+        return new IndexQuery<>(valCls.getName(), idxName, schema);
+    }
+
+    /** Less Then. */
+    public IndexQuery<K, V> lt(String field, Object val) {
+        A.ensure(idxCond == null, "The only index condition is supported.");
+
+        RangeIndexCondition cond = new RangeIndexCondition();
+
+        cond.addCondition(field, null, wrapNull(val));
+
+        idxCond = cond;
+
+        return this;
+    }
+
+    /** Less Then. */
+    public IndexQuery<K, V> lt(String field, Object val, String field2, Object... vals) {
+        A.ensure(idxCond == null, "The only index condition is supported.");
+
+        A.notEmpty(vals, "vals");
+        A.ensure(vals.length % 2 == 1, "number of fields has to be equal number of values.");
+
+        RangeIndexCondition cond = new RangeIndexCondition();
+
+        cond.addCondition(field, null, wrapNull(val));
+        cond.addCondition(field2, null, wrapNull(vals[0]));
+
+        for (int i = 1; i + 1 < vals.length; i += 2) {
+            A.ensure(vals[i] instanceof String, "waited for field name but got " + vals[i]);
+
+            cond.addCondition((String) vals[i], null, wrapNull(vals[i + 1]));
+        }
+
+        idxCond = cond;
+
+        return this;
+    }
+
+    /** Less Then or Equal. */
+    public IndexQuery<K, V> lte(String field, Object val) {
+        lt(field, val);
+
+        ((RangeIndexCondition) idxCond).upperInclusive(true);
+
+        return this;
+    }
+
+    /** Less Then or Equal. */
+    public IndexQuery<K, V> lte(String field, Object val, String field2, Object... vals) {
+        lt(field, val, field2, vals);
+
+        ((RangeIndexCondition) idxCond).upperInclusive(true);
+
+        return this;
+    }
+
+    /** Greater Then. */
+    public IndexQuery<K, V> gt(String field, Object val) {
+        A.ensure(idxCond == null, "The only index condition is supported.");
+
+        RangeIndexCondition cond = new RangeIndexCondition();
+
+        cond.addCondition(field, wrapNull(val), null);
+
+        idxCond = cond;
+
+        return this;
+    }
+
+    /** Greater Then. */
+    public IndexQuery<K, V> gt(String field, Object val, String field2, Object... vals) {
+        A.ensure(idxCond == null, "The only index condition is supported.");
+
+        A.notEmpty(vals, "vals");
+        A.ensure(vals.length % 2 == 1, "number of fields has to be equal number of values.");
+
+        RangeIndexCondition cond = new RangeIndexCondition();
+
+        cond.addCondition(field, wrapNull(val), null);
+        cond.addCondition(field2, wrapNull(vals[0]), null);
+
+        for (int i = 1; i + 1 < vals.length; i += 2) {
+            A.ensure(vals[i] instanceof String, "waited for field name but got " + vals[i]);
+
+            cond.addCondition((String) vals[i], wrapNull(vals[i + 1]), null);
+        }
+
+        idxCond = cond;
+
+        return this;
+    }
+
+    /** Greater Then or Equal. */
+    public IndexQuery<K, V> gte(String field, Object val) {
+        gt(field, val);
+
+        ((RangeIndexCondition) idxCond).lowerInclusive(true);
+
+        return this;
+    }
+
+    /** Greater Then or Equal. */
+    public IndexQuery<K, V> gte(String field, Object val, String field2, Object... vals) {
+        gt(field, val, field2, vals);
+
+        ((RangeIndexCondition) idxCond).lowerInclusive(true);
+
+        return this;
+    }
+
+    /** Between. Lower and upper boundaries are inclusive. */
+    public IndexQuery<K, V> between(String field, Object lower, Object upper) {
+        A.ensure(idxCond == null, "The only index condition is supported.");
+
+        RangeIndexCondition cond = new RangeIndexCondition();
+
+        cond.addCondition(field, wrapNull(lower), wrapNull(upper));
+
+        cond.lowerInclusive(true);
+        cond.upperInclusive(true);
+
+        idxCond = cond;
+
+        return this;
+    }
+
+    /** Between. Lower and upper boundaries are inclusive. */
+    public IndexQuery<K, V> between(String field, Object lower, Object upper, String field2, Object... vals) {

Review comment:
       I'm not sure that chaining is good approach. Code looks clearly but actually it's not true. For example:
   ```
   IndexQuery.forIndex()
       .lt("fieldA", 1)
       .lt("fieldB", 2)
   ```
   
   There has to be a complex validation that different chain parts should be consistent:
   1. No gt() and lt() together on the same query;
   2. From other side it's OK to combine between() with other range methods;
   3. That max() or min() methods are the only methods.
   
   Also Repeating multiple times "lt" declaration is weird. It's enough to declare condition once, then we need only provide list of fields. 
   
   I think that alternative can be introducing a IndexField class that is argument of all index operations (varags too). 
   
   ```
   IndexQuery().forIndex()
       .lt(field("fieldA", 1))
       .pageSize(1024);
   
   IndexQuery().forIndex()
       .lt(
           field("fieldA", 1),
           field("fieldB", 2))
       .pageSize(1024);
   
   IndexQuery().forIndex()
       .between(
           field("fieldA", 1, 2),
           field("fieldB", 2, 3))
       .pageSize(1024);
   
   static IndexFieldCondition field(String field, Object val, Object? val2) { return new IndexFieldCondition(field, val, val2); }
   
   ```
   
   In this case it a little bit verbose for single field index, but looks OK for multiple fields index. 
   
   WDYT?
   




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to 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