Use SPI in High Level Rest Client to load XContent parsers

client/rest-high-level/src/main/java/org/elasticsearch/client/RestHighLevelClient.java

@@ -49,8 +49,7 @@
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.common.xcontent.XContentType;
-import org.elasticsearch.join.aggregations.ChildrenAggregationBuilder;
-import org.elasticsearch.join.aggregations.ParsedChildren;
+import org.elasticsearch.plugins.spi.NamedXContentProvider;
 import org.elasticsearch.rest.BytesRestResponse;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.search.aggregations.Aggregation;
@@ -92,8 +91,6 @@
 import org.elasticsearch.search.aggregations.bucket.terms.ParsedLongTerms;
 import org.elasticsearch.search.aggregations.bucket.terms.ParsedStringTerms;
 import org.elasticsearch.search.aggregations.bucket.terms.StringTerms;
-import org.elasticsearch.search.aggregations.matrix.stats.MatrixStatsAggregationBuilder;
-import org.elasticsearch.search.aggregations.matrix.stats.ParsedMatrixStats;
 import org.elasticsearch.search.aggregations.metrics.avg.AvgAggregationBuilder;
 import org.elasticsearch.search.aggregations.metrics.avg.ParsedAvg;
 import org.elasticsearch.search.aggregations.metrics.cardinality.CardinalityAggregationBuilder;
@@ -142,11 +139,13 @@
 import org.elasticsearch.search.suggest.term.TermSuggestion;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.ServiceLoader;
 import java.util.Set;
 import java.util.function.Function;
 import java.util.stream.Collectors;
@@ -180,8 +179,9 @@ public RestHighLevelClient(RestClient restClient) {
      */
     protected RestHighLevelClient(RestClient restClient, List<NamedXContentRegistry.Entry> namedXContentEntries) {
         this.client = Objects.requireNonNull(restClient);
-        this.registry = new NamedXContentRegistry(Stream.of(getDefaultNamedXContents().stream(), namedXContentEntries.stream())
-                .flatMap(Function.identity()).collect(toList()));
+        this.registry = new NamedXContentRegistry(
+                Stream.of(getDefaultNamedXContents().stream(), getProvidedNamedXContents().stream(), namedXContentEntries.stream())
+                    .flatMap(Function.identity()).collect(toList()));
     }
 
     /**
@@ -566,8 +566,6 @@ static List<NamedXContentRegistry.Entry> getDefaultNamedXContents() {
         map.put(SignificantLongTerms.NAME, (p, c) -> ParsedSignificantLongTerms.fromXContent(p, (String) c));
         map.put(SignificantStringTerms.NAME, (p, c) -> ParsedSignificantStringTerms.fromXContent(p, (String) c));
         map.put(ScriptedMetricAggregationBuilder.NAME, (p, c) -> ParsedScriptedMetric.fromXContent(p, (String) c));
-        map.put(ChildrenAggregationBuilder.NAME, (p, c) -> ParsedChildren.fromXContent(p, (String) c));
-        map.put(MatrixStatsAggregationBuilder.NAME, (p, c) -> ParsedMatrixStats.fromXContent(p, (String) c));
         List<NamedXContentRegistry.Entry> entries = map.entrySet().stream()
                 .map(entry -> new NamedXContentRegistry.Entry(Aggregation.class, new ParseField(entry.getKey()), entry.getValue()))
                 .collect(Collectors.toList());
@@ -579,4 +577,15 @@ static List<NamedXContentRegistry.Entry> getDefaultNamedXContents() {
                 (parser, context) -> CompletionSuggestion.fromXContent(parser, (String)context)));
         return entries;
     }
+
+    /**
+     * Loads and returns the {@link NamedXContentRegistry.Entry} parsers provided by plugins.
+     */
+    static List<NamedXContentRegistry.Entry> getProvidedNamedXContents() {
+        List<NamedXContentRegistry.Entry> entries = new ArrayList<>();
+        for (NamedXContentProvider service : ServiceLoader.load(NamedXContentProvider.class)) {
+            entries.addAll(service.getNamedXContentParsers());
+        }
+        return entries;
+    }
 }

client/rest-high-level/src/test/java/org/elasticsearch/client/RestHighLevelClientTests.java

@@ -56,10 +56,12 @@
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.common.xcontent.cbor.CborXContent;
 import org.elasticsearch.common.xcontent.smile.SmileXContent;
+import org.elasticsearch.join.aggregations.ChildrenAggregationBuilder;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.search.SearchHits;
 import org.elasticsearch.search.aggregations.Aggregation;
 import org.elasticsearch.search.aggregations.InternalAggregations;
+import org.elasticsearch.search.aggregations.matrix.stats.MatrixStatsAggregationBuilder;
 import org.elasticsearch.search.suggest.Suggest;
 import org.elasticsearch.test.ESTestCase;
 import org.junit.Before;
@@ -69,6 +71,7 @@
 
 import java.io.IOException;
 import java.net.SocketTimeoutException;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
@@ -613,9 +616,9 @@ public void testWrapResponseListenerOnResponseExceptionWithIgnoresErrorValidBody
         assertEquals("Elasticsearch exception [type=exception, reason=test error message]", elasticsearchException.getMessage());
     }
 
-    public void testNamedXContents() {
+    public void testDefaultNamedXContents() {
         List<NamedXContentRegistry.Entry> namedXContents = RestHighLevelClient.getDefaultNamedXContents();
-        assertEquals(45, namedXContents.size());
+        assertEquals(43, namedXContents.size());
         Map<Class<?>, Integer> categories = new HashMap<>();
         for (NamedXContentRegistry.Entry namedXContent : namedXContents) {
             Integer counter = categories.putIfAbsent(namedXContent.categoryClass, 1);
@@ -624,10 +627,28 @@ public void testNamedXContents() {
             }
         }
         assertEquals(2, categories.size());
-        assertEquals(Integer.valueOf(42), categories.get(Aggregation.class));
+        assertEquals(Integer.valueOf(40), categories.get(Aggregation.class));
         assertEquals(Integer.valueOf(3), categories.get(Suggest.Suggestion.class));
     }
 
+    public void testProvidedNamedXContents() {
+        List<NamedXContentRegistry.Entry> namedXContents = RestHighLevelClient.getProvidedNamedXContents();
+        assertEquals(2, namedXContents.size());
+        Map<Class<?>, Integer> categories = new HashMap<>();
+        List<String> names = new ArrayList<>();
+        for (NamedXContentRegistry.Entry namedXContent : namedXContents) {
+            names.add(namedXContent.name.getPreferredName());
+            Integer counter = categories.putIfAbsent(namedXContent.categoryClass, 1);
+            if (counter != null) {
+                categories.put(namedXContent.categoryClass, counter + 1);
+            }
+        }
+        assertEquals(1, categories.size());
+        assertEquals(Integer.valueOf(2), categories.get(Aggregation.class));
+        assertTrue(names.contains(ChildrenAggregationBuilder.NAME));
+        assertTrue(names.contains(MatrixStatsAggregationBuilder.NAME));
+    }
+
     private static class TrackingActionListener implements ActionListener<Integer> {
         private final AtomicInteger statusCode = new AtomicInteger(-1);
         private final AtomicReference<Exception> exception = new AtomicReference<>();

core/src/main/java/org/elasticsearch/plugins/spi/NamedXContentProvider.java

@@ -0,0 +1,35 @@
+/*
+ * 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.plugins.spi;
+
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+
+import java.util.List;
+
+/**
+ * Provides named XContent parsers.
+ */
+public interface NamedXContentProvider {
+
+    /**
+     * @return a list of {@link NamedXContentRegistry.Entry} that this plugin provides.
+     */
+    List<NamedXContentRegistry.Entry> getNamedXContentParsers();
+}

core/src/main/java/org/elasticsearch/plugins/spi/package-info.java

@@ -0,0 +1,25 @@
+/*
+ * 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.
+ */
+
+/**
+ * This package contains interfaces for services provided by
+ * Elasticsearch plugins to external applications like the
+ * Java High Level Rest Client.
+ */
+package org.elasticsearch.plugins.spi;

core/src/test/java/org/elasticsearch/plugins/spi/NamedXContentProviderTests.java

@@ -0,0 +1,81 @@
+/*
+ * 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.plugins.spi;
+
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.io.Streams;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.search.aggregations.Aggregation;
+import org.elasticsearch.search.aggregations.pipeline.ParsedSimpleValue;
+import org.elasticsearch.search.suggest.Suggest;
+import org.elasticsearch.search.suggest.term.TermSuggestion;
+import org.elasticsearch.test.ESTestCase;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.ServiceLoader;
+import java.util.function.Predicate;
+
+public class NamedXContentProviderTests extends ESTestCase {
+
+    public void testSpiFileExists() throws IOException {
+        String serviceFile = "/META-INF/services/" + NamedXContentProvider.class.getName();
+        List<String> implementations = new ArrayList<>();
+        try (InputStream input = NamedXContentProviderTests.class.getResourceAsStream(serviceFile)) {
+            Streams.readAllLines(input, implementations::add);
+        }
+
+        assertEquals(1, implementations.size());
+        assertEquals(TestNamedXContentProvider.class.getName(), implementations.get(0));
+    }
+
+    public void testNamedXContents() {
+        final List<NamedXContentRegistry.Entry> namedXContents = new ArrayList<>();
+        for (NamedXContentProvider service : ServiceLoader.load(NamedXContentProvider.class)) {
+            namedXContents.addAll(service.getNamedXContentParsers());
+        }
+
+        assertEquals(2, namedXContents.size());
+
+        List<Predicate<NamedXContentRegistry.Entry>> predicates = new ArrayList<>(2);
+        predicates.add(e -> Aggregation.class.equals(e.categoryClass) && "test_aggregation".equals(e.name.getPreferredName()));
+        predicates.add(e -> Suggest.Suggestion.class.equals(e.categoryClass) && "test_suggestion".equals(e.name.getPreferredName()));
+        predicates.forEach(predicate -> assertEquals(1, namedXContents.stream().filter(predicate).count()));
+    }
+
+    public static class TestNamedXContentProvider implements NamedXContentProvider {
+
+        public TestNamedXContentProvider() {
+        }
+
+        @Override
+        public List<NamedXContentRegistry.Entry> getNamedXContentParsers() {
+            return Arrays.asList(
+                    new NamedXContentRegistry.Entry(Aggregation.class, new ParseField("test_aggregation"),
+                            (parser, context) -> ParsedSimpleValue.fromXContent(parser, (String) context)),
+                    new NamedXContentRegistry.Entry(Suggest.Suggestion.class, new ParseField("test_suggestion"),
+                            (parser, context) -> TermSuggestion.fromXContent(parser, (String) context))
+            );
+        }
+    }
+}

core/src/test/resources/META-INF/services/org.elasticsearch.plugins.spi.NamedXContentProvider

@@ -0,0 +1 @@
+org.elasticsearch.plugins.spi.NamedXContentProviderTests$TestNamedXContentProvider

modules/aggs-matrix-stats/src/main/java/org/elasticsearch/search/aggregations/matrix/spi/MatrixStatsNamedXContentProvider.java

@@ -0,0 +1,42 @@
+/*
+ * 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.matrix.spi;
+
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.xcontent.ContextParser;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.plugins.spi.NamedXContentProvider;
+import org.elasticsearch.search.aggregations.Aggregation;
+import org.elasticsearch.search.aggregations.matrix.stats.MatrixStatsAggregationBuilder;
+import org.elasticsearch.search.aggregations.matrix.stats.ParsedMatrixStats;
+
+import java.util.List;
+
+import static java.util.Collections.singletonList;
+
+public class MatrixStatsNamedXContentProvider implements NamedXContentProvider {
+
+    @Override
+    public List<NamedXContentRegistry.Entry> getNamedXContentParsers() {
+        ParseField parseField = new ParseField(MatrixStatsAggregationBuilder.NAME);
+        ContextParser<Object, Aggregation> contextParser = (p, name) -> ParsedMatrixStats.fromXContent(p, (String) name);
+        return singletonList(new NamedXContentRegistry.Entry(Aggregation.class, parseField, contextParser));
+    }
+}

modules/aggs-matrix-stats/src/main/resources/META-INF/services/org.elasticsearch.plugins.spi.NamedXContentProvider

@@ -0,0 +1 @@
+org.elasticsearch.search.aggregations.matrix.spi.MatrixStatsNamedXContentProvider

modules/parent-join/src/main/java/org/elasticsearch/join/spi/ParentJoinNamedXContentProvider.java

@@ -0,0 +1,42 @@
+/*
+ * 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.join.spi;
+
+import org.elasticsearch.common.ParseField;
+import org.elasticsearch.common.xcontent.ContextParser;
+import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.join.aggregations.ChildrenAggregationBuilder;
+import org.elasticsearch.join.aggregations.ParsedChildren;
+import org.elasticsearch.plugins.spi.NamedXContentProvider;
+import org.elasticsearch.search.aggregations.Aggregation;
+
+import java.util.List;
+
+import static java.util.Collections.singletonList;
+
+public class ParentJoinNamedXContentProvider implements NamedXContentProvider {
+
+    @Override
+    public List<NamedXContentRegistry.Entry> getNamedXContentParsers() {
+        ParseField parseField = new ParseField(ChildrenAggregationBuilder.NAME);
+        ContextParser<Object, Aggregation> contextParser = (p, name) -> ParsedChildren.fromXContent(p, (String) name);
+        return singletonList(new NamedXContentRegistry.Entry(Aggregation.class, parseField, contextParser));
+    }
+}

modules/parent-join/src/main/resources/META-INF/services/org.elasticsearch.plugins.spi.NamedXContentProvider

@@ -0,0 +1 @@
+org.elasticsearch.join.spi.ParentJoinNamedXContentProvider