| /* |
| * 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.WritableComparable; |
| |
| import java.io.IOException; |
| import javax.annotation.concurrent.NotThreadSafe; |
| |
| /** |
| * Special iterator that reuses vertex ids and data objects 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. |
| * |
| * @param <I> vertexId type parameter |
| * @param <T> vertexData type parameter |
| */ |
| @NotThreadSafe |
| public class ByteStructVertexIdDataIterator<I extends WritableComparable, T> |
| extends ByteStructVertexIdIterator<I> implements VertexIdDataIterator<I, T> { |
| /** VertexIdData to iterate over */ |
| protected AbstractVertexIdData<I, T> vertexIdData; |
| /** Serialized size of the message object in bytestore */ |
| protected int dataSize; |
| /** Current data. */ |
| private T data; |
| |
| /** |
| * Constructor |
| * |
| * @param vertexIdData vertexIdData |
| */ |
| public ByteStructVertexIdDataIterator( |
| AbstractVertexIdData<I, T> vertexIdData) { |
| super(vertexIdData.extendedDataOutput, vertexIdData.getConf()); |
| this.vertexIdData = vertexIdData; |
| } |
| |
| @Override |
| public void next() { |
| if (vertexId == null) { |
| vertexId = vertexIdData.getConf().createVertexId(); |
| } |
| if (data == null) { |
| data = vertexIdData.createData(); |
| } |
| try { |
| vertexId.readFields(extendedDataInput); |
| int initial = extendedDataInput.getPos(); |
| vertexIdData.readData(extendedDataInput, data); |
| dataSize = extendedDataInput.getPos() - initial; |
| } catch (IOException e) { |
| throw new IllegalStateException("next: IOException", e); |
| } |
| } |
| |
| @Override |
| public int getCurrentDataSize() { |
| return dataSize; |
| } |
| |
| @Override |
| public T getCurrentData() { |
| return data; |
| } |
| |
| @Override |
| public T releaseCurrentData() { |
| T releasedData = data; |
| data = null; |
| return releasedData; |
| } |
| } |