allow to provide fields for multi get

modules/elasticsearch/src/main/java/org/elasticsearch/action/get/MultiGetRequest.java

@@ -44,6 +44,7 @@ public class MultiGetRequest implements ActionRequest {
         private String type;
         private String id;
         private String routing;
+        private String[] fields;
 
         Item() {
 
@@ -86,6 +87,15 @@ public class MultiGetRequest implements ActionRequest {
             return this.routing;
         }
 
+        public Item fields(String... fields) {
+            this.fields = fields;
+            return this;
+        }
+
+        public String[] fields() {
+            return this.fields;
+        }
+
         public static Item readItem(StreamInput in) throws IOException {
             Item item = new Item();
             item.readFrom(in);
@@ -101,6 +111,13 @@ public class MultiGetRequest implements ActionRequest {
             if (in.readBoolean()) {
                 routing = in.readUTF();
             }
+            int size = in.readVInt();
+            if (size > 0) {
+                fields = new String[size];
+                for (int i = 0; i < size; i++) {
+                    fields[i] = in.readUTF();
+                }
+            }
         }
 
         @Override public void writeTo(StreamOutput out) throws IOException {
@@ -118,6 +135,14 @@ public class MultiGetRequest implements ActionRequest {
                 out.writeBoolean(true);
                 out.writeUTF(routing);
             }
+            if (fields == null) {
+                out.writeVInt(0);
+            } else {
+                out.writeVInt(fields.length);
+                for (String field : fields) {
+                    out.writeUTF(field);
+                }
+            }
         }
     }
 
@@ -216,6 +241,7 @@ public class MultiGetRequest implements ActionRequest {
                             String type = defaultType;
                             String id = null;
                             String routing = null;
+                            List<String> fields = null;
                             while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
                                 if (token == XContentParser.Token.FIELD_NAME) {
                                     currentFieldName = parser.currentName();
@@ -229,9 +255,16 @@ public class MultiGetRequest implements ActionRequest {
                                     } else if ("_routing".equals(currentFieldName) || "routing".equals(currentFieldName)) {
                                         routing = parser.text();
                                     }
+                                } else if (token == XContentParser.Token.START_ARRAY) {
+                                    if ("fields".equals(currentFieldName)) {
+                                        fields = new ArrayList<String>();
+                                        while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                                            fields.add(parser.text());
+                                        }
+                                    }
                                 }
                             }
-                            add(new Item(index, type, id).routing(routing));
+                            add(new Item(index, type, id).routing(routing).fields(fields == null ? null : fields.toArray(new String[fields.size()])));
                         }
                     } else if ("ids".equals(currentFieldName)) {
                         while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {

modules/elasticsearch/src/main/java/org/elasticsearch/action/get/MultiGetShardRequest.java

@@ -39,6 +39,7 @@ public class MultiGetShardRequest extends SingleShardOperationRequest {
     TIntArrayList locations;
     List<String> types;
     List<String> ids;
+    List<String[]> fields;
 
     MultiGetShardRequest() {
 
@@ -50,6 +51,7 @@ public class MultiGetShardRequest extends SingleShardOperationRequest {
         locations = new TIntArrayList();
         types = new ArrayList<String>();
         ids = new ArrayList<String>();
+        fields = new ArrayList<String[]>();
     }
 
     public int shardId() {
@@ -88,10 +90,11 @@ public class MultiGetShardRequest extends SingleShardOperationRequest {
         return this;
     }
 
-    public void add(int location, @Nullable String type, String id) {
+    public void add(int location, @Nullable String type, String id, String[] fields) {
-        locations.add(location);
+        this.locations.add(location);
-        types.add(type);
+        this.types.add(type);
-        ids.add(id);
+        this.ids.add(id);
+        this.fields.add(fields);
     }
 
     @Override public void readFrom(StreamInput in) throws IOException {
@@ -100,6 +103,7 @@ public class MultiGetShardRequest extends SingleShardOperationRequest {
         locations = new TIntArrayList(size);
         types = new ArrayList<String>(size);
         ids = new ArrayList<String>(size);
+        fields = new ArrayList<String[]>(size);
         for (int i = 0; i < size; i++) {
             locations.add(in.readVInt());
             if (in.readBoolean()) {
@@ -108,6 +112,16 @@ public class MultiGetShardRequest extends SingleShardOperationRequest {
                 types.add(null);
             }
             ids.add(in.readUTF());
+            int size1 = in.readVInt();
+            if (size1 > 0) {
+                String[] fields = new String[size1];
+                for (int j = 0; j < size1; j++) {
+                    fields[j] = in.readUTF();
+                }
+                this.fields.add(fields);
+            } else {
+                fields.add(null);
+            }
         }
 
         if (in.readBoolean()) {
@@ -134,6 +148,14 @@ public class MultiGetShardRequest extends SingleShardOperationRequest {
                 out.writeUTF(types.get(i));
             }
             out.writeUTF(ids.get(i));
+            if (fields.get(i) == null) {
+                out.writeVInt(0);
+            } else {
+                out.writeVInt(fields.get(i).length);
+                for (String field : fields.get(i)) {
+                    out.writeUTF(field);
+                }
+            }
         }
 
         if (preference == null) {

modules/elasticsearch/src/main/java/org/elasticsearch/action/get/TransportMultiGetAction.java

@@ -67,7 +67,7 @@ public class TransportMultiGetAction extends BaseAction<MultiGetRequest, MultiGe
 
                 shardRequests.put(shardId, shardRequest);
             }
-            shardRequest.add(i, item.type(), item.id());
+            shardRequest.add(i, item.type(), item.id(), item.fields());
         }
 
         final MultiGetItemResponse[] responses = new MultiGetItemResponse[request.items.size()];

modules/elasticsearch/src/main/java/org/elasticsearch/action/get/TransportShardMultiGetAction.java

@@ -102,9 +102,10 @@ public class TransportShardMultiGetAction extends TransportShardSingleOperationA
         for (int i = 0; i < request.locations.size(); i++) {
             String type = request.types.get(i);
             String id = request.ids.get(i);
+            String[] fields = request.fields.get(i);
 
             try {
-                GetResponse getResponse = TransportGetAction.load(logger, scriptService, indexService, indexShard, request.index(), type, id, null, request.realtime());
+                GetResponse getResponse = TransportGetAction.load(logger, scriptService, indexService, indexShard, request.index(), type, id, fields, request.realtime());
                 response.add(request.locations.get(i), getResponse);
             } catch (Exception e) {
                 response.add(request.locations.get(i), new MultiGetResponse.Failure(request.index(), type, id, ExceptionsHelper.detailedMessage(e)));

modules/test/integration/src/test/java/org/elasticsearch/test/integration/document/GetActionTests.java

@@ -23,6 +23,7 @@ import org.elasticsearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.elasticsearch.action.admin.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.action.delete.DeleteResponse;
 import org.elasticsearch.action.get.GetResponse;
+import org.elasticsearch.action.get.MultiGetRequest;
 import org.elasticsearch.action.get.MultiGetResponse;
 import org.elasticsearch.client.Client;
 import org.elasticsearch.common.settings.ImmutableSettings;
@@ -176,5 +177,15 @@ public class GetActionTests extends AbstractNodesTests {
         assertThat(response.responses()[3].response().exists(), equalTo(true));
         assertThat(response.responses()[4].id(), equalTo("11"));
         assertThat(response.responses()[4].response().exists(), equalTo(false));
+
+        // multi get with specific field
+        response = client.prepareMultiGet()
+                .add(new MultiGetRequest.Item("test", "type1", "1").fields("field"))
+                .add(new MultiGetRequest.Item("test", "type1", "3").fields("field"))
+                .execute().actionGet();
+
+        assertThat(response.responses().length, equalTo(2));
+        assertThat(response.responses()[0].response().source(), nullValue());
+        assertThat(response.responses()[0].response().field("field").values().get(0).toString(), equalTo("value1"));
     }
 }