Added has_parent query

The `has_parent` query works the same as the `has_parent` filter, by automatically wrapping the filter with a constant_score. It has the same syntax as the `has_parent` filter. Closes elastic#2254

src/main/java/org/elasticsearch/index/query/HasParentQueryBuilder.java

@@ -0,0 +1,92 @@
+/*
+ * Licensed to ElasticSearch and Shay Banon under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. ElasticSearch 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.elasticsearch.index.query;
+
+import org.elasticsearch.common.xcontent.XContentBuilder;
+
+import java.io.IOException;
+
+/**
+ * Builder for the 'has_parent' query.
+ */
+public class HasParentQueryBuilder extends BaseQueryBuilder implements BoostableQueryBuilder<HasParentQueryBuilder> {
+
+    private final QueryBuilder queryBuilder;
+    private final String parentType;
+    private String scope;
+    private String filterName;
+    private String executionType;
+    private float boost = 1.0f;
+
+    /**
+     * @param parentType The parent type
+     * @param parentQuery The query that will be matched with parent documents
+     */
+    public HasParentQueryBuilder(String parentType, QueryBuilder parentQuery) {
+        this.parentType = parentType;
+        this.queryBuilder = parentQuery;
+    }
+
+    public HasParentQueryBuilder scope(String scope) {
+        this.scope = scope;
+        return this;
+    }
+
+    public HasParentQueryBuilder filterName(String filterName) {
+        this.filterName = filterName;
+        return this;
+    }
+
+    /**
+     * Expert: Sets the low level parent to child filtering implementation. Can be: 'indirect' or 'uid'
+     *
+     * This option is experimental and will be removed.
+     */
+    public HasParentQueryBuilder executionType(String executionType) {
+        this.executionType = executionType;
+        return this;
+    }
+
+    public HasParentQueryBuilder boost(float boost) {
+        this.boost = boost;
+        return this;
+    }
+
+    protected void doXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.startObject(HasParentQueryParser.NAME);
+        builder.field("query");
+        queryBuilder.toXContent(builder, params);
+        builder.field("parent_type", parentType);
+        if (scope != null) {
+            builder.field("_scope", scope);
+        }
+        if (filterName != null) {
+            builder.field("_name", filterName);
+        }
+        if (executionType != null) {
+            builder.field("execution_type", executionType);
+        }
+        if (boost != 1.0f) {
+            builder.field("boost", boost);
+        }
+        builder.endObject();
+    }
+}
+

src/main/java/org/elasticsearch/index/query/HasParentQueryParser.java

@@ -0,0 +1,119 @@
+/*
+ * Licensed to ElasticSearch and Shay Banon under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. ElasticSearch 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.elasticsearch.index.query;
+
+import org.apache.lucene.search.ConstantScoreQuery;
+import org.apache.lucene.search.FilteredQuery;
+import org.apache.lucene.search.Query;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.inject.Inject;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.index.mapper.DocumentMapper;
+import org.elasticsearch.index.search.child.HasParentFilter;
+import org.elasticsearch.search.internal.SearchContext;
+
+import java.io.IOException;
+
+// Same parse logic HasParentQueryFilter, but also parses boost and wraps filter in constant score query
+public class HasParentQueryParser implements QueryParser {
+
+    public static final String NAME = "has_parent";
+
+    @Inject
+    public HasParentQueryParser() {
+    }
+
+    @Override
+    public String[] names() {
+        return new String[]{NAME, Strings.toCamelCase(NAME)};
+    }
+
+    @Override
+    public Query parse(QueryParseContext parseContext) throws IOException, QueryParsingException {
+        XContentParser parser = parseContext.parser();
+
+        Query query = null;
+        boolean queryFound = false;
+        float boost = 1.0f;
+        String parentType = null;
+        String executionType = "uid";
+        String scope = null;
+
+        String currentFieldName = null;
+        XContentParser.Token token;
+        while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
+            if (token == XContentParser.Token.FIELD_NAME) {
+                currentFieldName = parser.currentName();
+            } else if (token == XContentParser.Token.START_OBJECT) {
+                if ("query".equals(currentFieldName)) {
+                    // TODO handle `query` element before `type` element...
+                    String[] origTypes = QueryParseContext.setTypesWithPrevious(parentType == null ? null : new String[]{parentType});
+                    try {
+                        query = parseContext.parseInnerQuery();
+                        queryFound = true;
+                    } finally {
+                        QueryParseContext.setTypes(origTypes);
+                    }
+                } else {
+                    throw new QueryParsingException(parseContext.index(), "[has_parent] filter does not support [" + currentFieldName + "]");
+                }
+            } else if (token.isValue()) {
+                if ("type".equals(currentFieldName) || "parent_type".equals(currentFieldName) || "parentType".equals(currentFieldName)) {
+                    parentType = parser.text();
+                } else if ("_scope".equals(currentFieldName)) {
+                    scope = parser.text();
+                } else if ("execution_type".equals(currentFieldName) || "executionType".equals(currentFieldName)) { // This option is experimental and will most likely be removed.
+                    executionType = parser.text();
+                } else if ("boost".equals(currentFieldName)) {
+                    boost = parser.floatValue();
+                } else {
+                    throw new QueryParsingException(parseContext.index(), "[has_parent] filter does not support [" + currentFieldName + "]");
+                }
+            }
+        }
+        if (!queryFound) {
+            throw new QueryParsingException(parseContext.index(), "[parent] filter requires 'query' field");
+        }
+        if (query == null) {
+            return null;
+        }
+
+        if (parentType == null) {
+            throw new QueryParsingException(parseContext.index(), "[parent] filter requires 'parent_type' field");
+        }
+
+        DocumentMapper parentDocMapper = parseContext.mapperService().documentMapper(parentType);
+        if (parentDocMapper == null) {
+            throw new QueryParsingException(parseContext.index(), "[parent] filter configured 'parent_type' [" + parentType + "] is not a valid type");
+        }
+
+        query.setBoost(boost);
+        // wrap the query with type query
+        query = new FilteredQuery(query, parseContext.cacheFilter(parentDocMapper.typeFilter(), null));
+        SearchContext searchContext = SearchContext.current();
+        HasParentFilter parentFilter = HasParentFilter.create(executionType, query, scope, parentType, searchContext);
+
+        ConstantScoreQuery parentQuery = new ConstantScoreQuery(parentFilter);
+        parentQuery.setBoost(boost);
+        searchContext.addScopePhase(parentFilter);
+        return parentQuery;
+    }
+
+}

src/main/java/org/elasticsearch/index/query/QueryBuilders.java

@@ -551,6 +551,17 @@ public static HasChildQueryBuilder hasChildQuery(String type, QueryBuilder query
         return new HasChildQueryBuilder(type, query);
     }
 
+    /**
+     * Constructs a new NON scoring parent query, with the parent type and the query to run on the parent documents. The
+     * results of this query are the children docs that those parent docs matched.
+     *
+     * @param type  The parent type.
+     * @param query The query.
+     */
+    public static HasParentQueryBuilder hasParentQuery(String type, QueryBuilder query) {
+        return new HasParentQueryBuilder(type, query);
+    }
+
     public static NestedQueryBuilder nestedQuery(String path, QueryBuilder query) {
         return new NestedQueryBuilder(path, query);
     }

src/main/java/org/elasticsearch/indices/query/IndicesQueriesRegistry.java

@@ -45,6 +45,7 @@ public IndicesQueriesRegistry(Settings settings, @Nullable ClusterService cluste
         addQueryParser(queryParsers, new MultiMatchQueryParser());
         addQueryParser(queryParsers, new NestedQueryParser());
         addQueryParser(queryParsers, new HasChildQueryParser());
+        addQueryParser(queryParsers, new HasParentQueryParser());
         addQueryParser(queryParsers, new TopChildrenQueryParser());
         addQueryParser(queryParsers, new DisMaxQueryParser());
         addQueryParser(queryParsers, new IdsQueryParser());

src/test/java/org/elasticsearch/test/integration/search/child/SimpleChildQuerySearchTests.java

@@ -267,6 +267,21 @@ public void simpleChildQuery() throws Exception {
         assertThat(searchResponse.hits().totalHits(), equalTo(2l));
         assertThat(searchResponse.hits().getAt(0).id(), equalTo("c1"));
         assertThat(searchResponse.hits().getAt(1).id(), equalTo("c2"));
+
+        // HAS PARENT QUERY
+        searchResponse = client.prepareSearch("test").setQuery(hasParentQuery("parent", termQuery("p_field", "p_value2")).executionType(getExecutionMethod())).execute().actionGet();
+        assertThat("Failures " + Arrays.toString(searchResponse.shardFailures()), searchResponse.shardFailures().length, equalTo(0));
+        assertThat(searchResponse.failedShards(), equalTo(0));
+        assertThat(searchResponse.hits().totalHits(), equalTo(2l));
+        assertThat(searchResponse.hits().getAt(0).id(), equalTo("c3"));
+        assertThat(searchResponse.hits().getAt(1).id(), equalTo("c4"));
+
+        searchResponse = client.prepareSearch("test").setQuery(hasParentQuery("parent", termQuery("p_field", "p_value1")).executionType(getExecutionMethod())).execute().actionGet();
+        assertThat("Failures " + Arrays.toString(searchResponse.shardFailures()), searchResponse.shardFailures().length, equalTo(0));
+        assertThat(searchResponse.failedShards(), equalTo(0));
+        assertThat(searchResponse.hits().totalHits(), equalTo(2l));
+        assertThat(searchResponse.hits().getAt(0).id(), equalTo("c1"));
+        assertThat(searchResponse.hits().getAt(1).id(), equalTo("c2"));
     }
 
     @Test