ValuesSource refactoring: wire up Missing aggregation

server/src/main/java/org/elasticsearch/search/SearchModule.java

@@ -381,7 +381,9 @@ private void registerAggregations(List<SearchPlugin> plugins) {
         registerAggregation(new AggregationSpec(GlobalAggregationBuilder.NAME, GlobalAggregationBuilder::new,
                 GlobalAggregationBuilder::parse).addResultReader(InternalGlobal::new));
         registerAggregation(new AggregationSpec(MissingAggregationBuilder.NAME, MissingAggregationBuilder::new,
-                MissingAggregationBuilder.PARSER).addResultReader(InternalMissing::new));
+                MissingAggregationBuilder.PARSER)
+                    .addResultReader(InternalMissing::new)
+                    .setAggregatorRegistrar(MissingAggregationBuilder::registerAggregators));
         registerAggregation(new AggregationSpec(FilterAggregationBuilder.NAME, FilterAggregationBuilder::new,
                 FilterAggregationBuilder::parse).addResultReader(InternalFilter::new));
         registerAggregation(new AggregationSpec(FiltersAggregationBuilder.NAME, FiltersAggregationBuilder::new,

server/src/main/java/org/elasticsearch/search/aggregations/bucket/missing/MissingAggregationBuilder.java

@@ -32,6 +32,7 @@
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregationBuilder;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
 import org.elasticsearch.search.aggregations.support.ValuesSourceConfig;
+import org.elasticsearch.search.aggregations.support.ValuesSourceRegistry;
 import org.elasticsearch.search.aggregations.support.ValuesSourceType;
 
 import java.io.IOException;
@@ -46,6 +47,10 @@ public class MissingAggregationBuilder extends ValuesSourceAggregationBuilder<Mi
         ValuesSourceAggregationBuilder.declareFields(PARSER, true, true, false);
     }
 
+    public static void registerAggregators(ValuesSourceRegistry valuesSourceRegistry) {
+        MissingAggregatorFactory.registerAggregators(valuesSourceRegistry);
+    }
+
     public MissingAggregationBuilder(String name) {
         super(name);
     }

server/src/main/java/org/elasticsearch/search/aggregations/bucket/missing/MissingAggregatorFactory.java

@@ -20,13 +20,17 @@
 package org.elasticsearch.search.aggregations.bucket.missing;
 
 import org.elasticsearch.index.query.QueryShardContext;
+import org.elasticsearch.search.aggregations.AggregationExecutionException;
 import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.AggregatorFactories;
 import org.elasticsearch.search.aggregations.AggregatorFactory;
 import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
+import org.elasticsearch.search.aggregations.support.AggregatorSupplier;
+import org.elasticsearch.search.aggregations.support.CoreValuesSourceType;
 import org.elasticsearch.search.aggregations.support.ValuesSource;
 import org.elasticsearch.search.aggregations.support.ValuesSourceAggregatorFactory;
 import org.elasticsearch.search.aggregations.support.ValuesSourceConfig;
+import org.elasticsearch.search.aggregations.support.ValuesSourceRegistry;
 import org.elasticsearch.search.internal.SearchContext;
 
 import java.io.IOException;
@@ -35,6 +39,22 @@
 
 public class MissingAggregatorFactory extends ValuesSourceAggregatorFactory {
 
+    public static void registerAggregators(ValuesSourceRegistry valuesSourceRegistry) {
+        valuesSourceRegistry.register(
+            MissingAggregationBuilder.NAME,
+            List.of(
+                CoreValuesSourceType.NUMERIC,
+                CoreValuesSourceType.BYTES,
+                CoreValuesSourceType.GEOPOINT,
+                CoreValuesSourceType.RANGE,
+                CoreValuesSourceType.IP,
+                CoreValuesSourceType.BOOLEAN,
+                CoreValuesSourceType.DATE
+            ),
+            (MissingAggregatorSupplier) MissingAggregator::new
+        );
+    }
+
     public MissingAggregatorFactory(String name, ValuesSourceConfig config, QueryShardContext queryShardContext,
                                     AggregatorFactory parent, AggregatorFactories.Builder subFactoriesBuilder,
                                     Map<String, Object> metaData) throws IOException {
@@ -50,13 +70,22 @@ protected MissingAggregator createUnmapped(SearchContext searchContext,
     }
 
     @Override
-    protected MissingAggregator doCreateInternal(ValuesSource valuesSource,
+    protected Aggregator doCreateInternal(ValuesSource valuesSource,
                                                     SearchContext searchContext,
                                                     Aggregator parent,
                                                     boolean collectsFromSingleBucket,
                                                     List<PipelineAggregator> pipelineAggregators,
                                                     Map<String, Object> metaData) throws IOException {
-        return new MissingAggregator(name, factories, valuesSource, searchContext, parent, pipelineAggregators, metaData);
+
+        final AggregatorSupplier aggregatorSupplier = queryShardContext.getValuesSourceRegistry()
+            .getAggregator(config.valueSourceType(), MissingAggregationBuilder.NAME);
+        if (aggregatorSupplier instanceof MissingAggregatorSupplier == false) {
+            throw new AggregationExecutionException("Registry miss-match - expected MissingAggregatorSupplier, found [" +
+                aggregatorSupplier.getClass().toString() + "]");
+        }
+
+        return ((MissingAggregatorSupplier) aggregatorSupplier)
+            .build(name, factories, valuesSource, searchContext, parent, pipelineAggregators, metaData);
     }
 
 }

server/src/main/java/org/elasticsearch/search/aggregations/bucket/missing/MissingAggregatorSupplier.java

@@ -0,0 +1,44 @@
+/*
+ * 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.missing;
+
+import org.elasticsearch.common.Nullable;
+import org.elasticsearch.search.aggregations.Aggregator;
+import org.elasticsearch.search.aggregations.AggregatorFactories;
+import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
+import org.elasticsearch.search.aggregations.support.AggregatorSupplier;
+import org.elasticsearch.search.aggregations.support.ValuesSource;
+import org.elasticsearch.search.internal.SearchContext;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+@FunctionalInterface
+public interface MissingAggregatorSupplier extends AggregatorSupplier {
+
+    Aggregator build(String name,
+                     AggregatorFactories factories,
+                     @Nullable ValuesSource valuesSource,
+                     SearchContext aggregationContext,
+                     Aggregator parent,
+                     List<PipelineAggregator> pipelineAggregators,
+                     Map<String, Object> metaData) throws IOException;
+}