| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF 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.apache.giraph.graph; |
| |
| import java.io.IOException; |
| |
| import org.apache.hadoop.io.Writable; |
| import org.apache.hadoop.io.WritableComparable; |
| |
| /** |
| * Abstract class to extend for combining of messages sent to the same vertex. |
| * |
| * @param <I extends Writable> index |
| * @param <M extends Writable> message data |
| */ |
| @SuppressWarnings("rawtypes") |
| public abstract class VertexCombiner<I extends WritableComparable, |
| M extends Writable> { |
| |
| /** |
| * Combines message values for a particular vertex index. |
| * |
| * @param vertexIndex Index of the vertex getting these messages |
| * @param messages Iterable of the messages to be combined |
| * @return Iterable of the combined messages. The returned value cannot |
| * be null and its size is required to be smaller or equal to |
| * the size of {@link messages}. |
| * @throws IOException |
| */ |
| public abstract Iterable<M> combine(I vertexIndex, |
| Iterable<M> messages) throws IOException; |
| } |