| /* |
| * 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.utils; |
| |
| import org.apache.hadoop.io.Writable; |
| import org.apache.hadoop.io.WritableComparable; |
| |
| import java.io.IOException; |
| import javax.annotation.concurrent.NotThreadSafe; |
| |
| /** |
| * Special iterator that reuses vertex ids and messages bytes so that the |
| * lifetime of the object is only until next() is called. |
| * |
| * Vertex id ownership can be released if desired through |
| * releaseCurrentVertexId(). This optimization allows us to cut down |
| * on the number of objects instantiated and garbage collected. Messages |
| * can only be copied to an ExtendedDataOutput object |
| * |
| * @param <I> vertexId type parameter |
| * @param <M> message type parameter |
| */ |
| @NotThreadSafe |
| public abstract class ByteStructVertexIdMessageBytesIterator<I |
| extends WritableComparable, M extends Writable> |
| extends ByteStructVertexIdDataIterator<I, M> |
| implements VertexIdMessageBytesIterator<I, M> { |
| /** Last message offset */ |
| protected int messageOffset = -1; |
| /** Number of bytes in the last message */ |
| protected int messageBytes = -1; |
| |
| /** |
| * Constructor with vertexIdData |
| * |
| * @param vertexIdData vertexIdData |
| */ |
| public ByteStructVertexIdMessageBytesIterator( |
| AbstractVertexIdData<I, M> vertexIdData) { |
| super(vertexIdData); |
| } |
| |
| /** |
| * Moves to the next element in the iteration. |
| */ |
| @Override |
| public void next() { |
| if (vertexId == null) { |
| vertexId = vertexIdData.getConf().createVertexId(); |
| } |
| |
| try { |
| vertexId.readFields(extendedDataInput); |
| messageBytes = extendedDataInput.readInt(); |
| messageOffset = extendedDataInput.getPos(); |
| if (extendedDataInput.skipBytes(messageBytes) != messageBytes) { |
| throw new IllegalStateException("next: Failed to skip " + |
| messageBytes); |
| } |
| } catch (IOException e) { |
| throw new IllegalStateException("next: IOException", e); |
| } |
| } |
| } |