JCBC-1171 Allow to add hints for hash and nested loop joins in Query dsl

Change-Id: Ib651726f38514adcc2fef150e41265ad81255299
Reviewed-on: http://review.couchbase.org/102501
Reviewed-by: David Nault <david.nault@couchbase.com>
Tested-by: Subhashni Balakrishnan <b.subhashni@gmail.com>

src/main/java/com/couchbase/client/java/query/dsl/element/NestedLoopJoinHintElement.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2018 Couchbase, Inc.
+ *
+ * Licensed 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 com.couchbase.client.java.query.dsl.element;
+
+import com.couchbase.client.core.annotations.InterfaceAudience;
+import com.couchbase.client.core.annotations.InterfaceStability;
+
+/**
+ * Hint to use Nested loop join
+ *
+ * @author Subhashni Balakrishnan
+ */
+@InterfaceStability.Experimental
+@InterfaceAudience.Private
+public class NestedLoopJoinHintElement implements Element {
+
+    @Override
+    public String export() {
+        return "USE NL";
+    }
+}

src/main/java/com/couchbase/client/java/query/dsl/path/DefaultJoinPath.java

@@ -16,6 +16,7 @@
 package com.couchbase.client.java.query.dsl.path;
 
 import com.couchbase.client.java.query.dsl.element.AsElement;
+import com.couchbase.client.java.query.dsl.element.NestedLoopJoinHintElement;
 
 /**
  * .
@@ -29,8 +30,20 @@ public DefaultJoinPath(AbstractPath parent) {
     }
 
     @Override
-    public KeysPath as(String alias) {
+    public JoinPath as(String alias) {
         element(new AsElement(alias));
+        return new DefaultJoinPath(this);
+    }
+
+    @Override
+    public KeysPath useHash(HashSide side) {
+        element(new HashJoinHintElement(side));
+        return new DefaultKeysPath(this);
+    }
+
+    @Override
+    public KeysPath useNestedLoop() {
+        element(new NestedLoopJoinHintElement());
         return new DefaultKeysPath(this);
     }
 }

src/main/java/com/couchbase/client/java/query/dsl/path/HashJoinHintElement.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2018 Couchbase, Inc.
+ *
+ * Licensed 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 com.couchbase.client.java.query.dsl.path;
+
+import java.util.Objects;
+
+import com.couchbase.client.core.annotations.InterfaceAudience;
+import com.couchbase.client.core.annotations.InterfaceStability;
+import com.couchbase.client.java.query.dsl.element.Element;
+
+/**
+ * Hash Join hint for hash based join
+ *
+ * @author Subhashni Balakrishnan
+ */
+@InterfaceStability.Experimental
+@InterfaceAudience.Private
+public class HashJoinHintElement implements Element {
+
+    private final HashSide side;
+
+    public HashJoinHintElement(HashSide side) {
+        Objects.requireNonNull(side);
+        this.side = side;
+    }
+
+    @Override
+    public String export() {
+        return "USE HASH(" + this.side + ")";
+    }
+}

src/main/java/com/couchbase/client/java/query/dsl/path/HashSide.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2018 Couchbase, Inc.
+ *
+ * Licensed 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 com.couchbase.client.java.query.dsl.path;
+
+import com.couchbase.client.core.annotations.InterfaceAudience;
+import com.couchbase.client.core.annotations.InterfaceStability;
+
+/**
+ * Hash side for hash based join
+ *
+ * @author Subhashni Balakrishnan
+ */
+@InterfaceStability.Experimental
+@InterfaceAudience.Public
+public enum HashSide {
+
+    /**
+     * The PROBE side will use that table to find matches and perform the join
+     * */
+    PROBE("PROBE"),
+
+    /**
+     * The BUILD side of the join will be used to create an in-memory hash table
+     * */
+    BUILD("BUILD");
+
+    private final String value;
+
+    HashSide(String value) {
+        this.value = value;
+    }
+
+    @Override
+    public String toString() {
+        return this.value;
+    }
+}

src/main/java/com/couchbase/client/java/query/dsl/path/JoinPath.java

@@ -22,6 +22,15 @@
  */
 public interface JoinPath extends KeysPath {
 
-    KeysPath as(String alias);
+    JoinPath as(String alias);
 
+    /**
+     * Use hash join hint (Available in Enterprise Edition only)
+     */
+    KeysPath useHash(HashSide side);
+
+    /**
+     * Use nested loop join
+     */
+    KeysPath useNestedLoop();
 }

src/test/java/com/couchbase/client/java/query/dsl/SelectDslSmokeTest.java

@@ -42,6 +42,7 @@
 import com.couchbase.client.java.document.json.JsonArray;
 import com.couchbase.client.java.query.Statement;
 import com.couchbase.client.java.query.dsl.functions.DateFunctions;
+import com.couchbase.client.java.query.dsl.path.HashSide;
 import org.junit.Ignore;
 import org.junit.Test;
 
@@ -679,4 +680,33 @@ public void test56() {
 
         assertEquals("SELECT DISTINCT RAW name FROM authors", statement.toString());
     }
+
+    @Test
+    public void test57() {
+        Statement statement = selectDistinctRaw("books.authorName").from("A").as("books").join("A")
+                .as("authors").useHash(HashSide.PROBE).on(x("books.authorName").eq(x("authors.name")))
+                .where(x("books.type").eq(s("book")).and(x("authors.type").eq(s("author"))));
+
+        assertEquals("SELECT DISTINCT RAW books.authorName FROM A AS books JOIN A AS authors USE HASH(PROBE) ON " +
+                "books.authorName = authors.name WHERE books.type = \"book\" AND authors.type = \"author\"", statement.toString());
+    }
+
+    @Test
+    public void test58() {
+        Statement statement = selectDistinctRaw("books.authorName").from("A").as("books").join("A")
+                .as("authors").useHash(HashSide.BUILD).on(x("books.authorName").eq(x("authors.name")))
+                .where(x("books.type").eq(s("book")).and(x("authors.type").eq(s("author"))));
+
+        assertEquals("SELECT DISTINCT RAW books.authorName FROM A AS books JOIN A AS authors USE HASH(BUILD) ON " +
+                "books.authorName = authors.name WHERE books.type = \"book\" AND authors.type = \"author\"", statement.toString());
+    }
+
+    @Test
+    public void test59() {
+        Statement statement = selectDistinctRaw("books.authorName").from("A").as("books").join("A")
+                .as("authors").useNestedLoop().on(x("books.authorName").eq(x("authors.name"))).where(x("books.type").eq(s("book")).and(x("authors.type").eq(s("author"))));
+
+        assertEquals("SELECT DISTINCT RAW books.authorName FROM A AS books JOIN A AS authors USE NL ON " +
+                "books.authorName = authors.name WHERE books.type = \"book\" AND authors.type = \"author\"", statement.toString());
+    }
 }