Delete API: Allow to set _parent on it (will simply set the routing value), closes #742.

modules/elasticsearch/src/main/java/org/elasticsearch/action/bulk/BulkRequest.java

@@ -141,7 +141,7 @@ public class BulkRequest implements ActionRequest {
             }
 
             if ("delete".equals(action)) {
-                add(new DeleteRequest(index, type, id).routing(routing));
+                add(new DeleteRequest(index, type, id).parent(parent).routing(routing));
             } else {
                 nextMarker = findNextMarker(marker, from, data, length);
                 if (nextMarker == -1) {

modules/elasticsearch/src/main/java/org/elasticsearch/action/delete/DeleteRequest.java

@@ -167,6 +167,17 @@ public class DeleteRequest extends ShardReplicationOperationRequest {
         return this;
     }
 
+    /**
+     * Sets the parent id of this document. Will simply set the routing to this value, as it is only
+     * used for routing with delete requests.
+     */
+    public DeleteRequest parent(String parent) {
+        if (routing == null) {
+            routing = parent;
+        }
+        return this;
+    }
+
     /**
      * Controls the shard routing of the request. Using this value to hash the shard
      * and not the id.

modules/elasticsearch/src/main/java/org/elasticsearch/rest/action/delete/RestDeleteAction.java

@@ -50,6 +50,7 @@ public class RestDeleteAction extends BaseRestHandler {
 
     @Override public void handleRequest(final RestRequest request, final RestChannel channel) {
         DeleteRequest deleteRequest = new DeleteRequest(request.param("index"), request.param("type"), request.param("id"));
+        deleteRequest.parent(request.param("parent"));
         deleteRequest.routing(request.param("routing"));
         deleteRequest.timeout(request.paramAsTime("timeout", DeleteRequest.DEFAULT_TIMEOUT));
         deleteRequest.refresh(request.paramAsBoolean("refresh", deleteRequest.refresh()));