Aggregations Refactor: Refactor Global Aggregation

core/src/main/java/org/elasticsearch/search/aggregations/bucket/global/GlobalAggregator.java

@@ -19,6 +19,9 @@
 package org.elasticsearch.search.aggregations.bucket.global;
 
 import org.apache.lucene.index.LeafReaderContext;
+import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.search.aggregations.AggregationExecutionException;
 import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.AggregatorFactories;
@@ -87,5 +90,32 @@ public Aggregator createInternal(AggregationContext context, Aggregator parent,
             return new GlobalAggregator(name, factories, context, pipelineAggregators, metaData);
         }
 
+        @Override
+        protected AggregatorFactory doReadFrom(String name, StreamInput in) throws IOException {
+            return new Factory(name);
+        }
+
+        @Override
+        protected void doWriteTo(StreamOutput out) throws IOException {
+            // Nothing to write
+        }
+
+        @Override
+        protected XContentBuilder internalXContent(XContentBuilder builder, Params params) throws IOException {
+            builder.startObject();
+            builder.endObject();
+            return builder;
+        }
+
+        @Override
+        protected boolean doEquals(Object obj) {
+            return true;
+        }
+
+        @Override
+        protected int doHashCode() {
+            return 0;
+        }
+
     }
 }

core/src/main/java/org/elasticsearch/search/aggregations/bucket/global/GlobalParser.java

@@ -41,10 +41,9 @@ public AggregatorFactory parse(String aggregationName, XContentParser parser, Se
         return new GlobalAggregator.Factory(aggregationName);
     }
 
-    // NORELEASE implement this method when refactoring this aggregation
     @Override
     public AggregatorFactory getFactoryPrototype() {
-        return null;
+        return new GlobalAggregator.Factory(null);
     }
 
 }

core/src/test/java/org/elasticsearch/search/aggregations/bucket/GlobalTests.java

@@ -0,0 +1,33 @@
+/*
+ * Licensed to Elasticsearch 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.search.aggregations.bucket;
+
+import org.elasticsearch.search.aggregations.BaseAggregationTestCase;
+import org.elasticsearch.search.aggregations.bucket.global.GlobalAggregator;
+import org.elasticsearch.search.aggregations.bucket.global.GlobalAggregator.Factory;
+
+public class GlobalTests extends BaseAggregationTestCase<GlobalAggregator.Factory> {
+
+    @Override
+    protected Factory createTestAggregatorFactory() {
+        return new GlobalAggregator.Factory(randomAsciiOfLengthBetween(3, 20));
+    }
+
+}