| /* |
| * 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.edge; |
| |
| import org.apache.giraph.conf.ImmutableClassesGiraphConfiguration; |
| import org.apache.hadoop.io.Writable; |
| import org.apache.hadoop.io.WritableComparable; |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| import java.util.Iterator; |
| |
| /** |
| * Helper class that wraps the current out-edges and inserts them into a new |
| * data structure as they are iterated over. |
| * Used by Vertex to provide a mutable iterator when the chosen |
| * {@link OutEdges} doesn't offer a specialized one. |
| * The edges are "unwrapped" back to the chosen {@link OutEdges} data |
| * structure as soon as possible: either when the iterator is exhausted, |
| * or after compute() if iteration has been terminated early. |
| * |
| * @param <I> Vertex id |
| * @param <E> Edge value |
| */ |
| public class MutableEdgesWrapper<I extends WritableComparable, |
| E extends Writable> implements OutEdges<I, E> { |
| /** New edges data structure (initially empty). */ |
| private final OutEdges<I, E> newEdges; |
| /** Iterator over the old edges. */ |
| private final Iterator<Edge<I, E>> oldEdgesIterator; |
| /** Last edge that was returned during iteration. */ |
| private MutableEdge<I, E> currentEdge; |
| |
| /** |
| * Private constructor: instantiation happens through the {@code wrap()} |
| * factory method. |
| * |
| * @param oldEdges Current out-edges |
| * @param newEdges New (empty) edges data structure |
| */ |
| private MutableEdgesWrapper(OutEdges<I, E> oldEdges, |
| OutEdges<I, E> newEdges) { |
| oldEdgesIterator = oldEdges.iterator(); |
| this.newEdges = newEdges; |
| } |
| |
| /** |
| * Factory method to create a new wrapper over the existing out-edges. |
| * |
| * @param edges Current out-edges |
| * @param conf Configuration |
| * @param <I> Vertex id |
| * @param <E> Edge value |
| * @return The wrapped edges |
| */ |
| public static <I extends WritableComparable, E extends Writable> |
| MutableEdgesWrapper<I, E> wrap( |
| OutEdges<I, E> edges, |
| ImmutableClassesGiraphConfiguration<I, ?, E, ?> conf) { |
| MutableEdgesWrapper<I, E> wrapper = new MutableEdgesWrapper<I, E>( |
| edges, conf.createAndInitializeOutEdges(edges.size())); |
| return wrapper; |
| } |
| |
| /** |
| * Moves all the remaining edges to the new data structure, and returns it. |
| * |
| * @return The new {@link OutEdges} data structure. |
| */ |
| public OutEdges<I, E> unwrap() { |
| if (currentEdge != null) { |
| newEdges.add(currentEdge); |
| currentEdge = null; |
| } |
| while (oldEdgesIterator.hasNext()) { |
| newEdges.add(oldEdgesIterator.next()); |
| } |
| return newEdges; |
| } |
| |
| /** |
| * Get the new {@link OutEdges} data structure. |
| * |
| * @return New edges |
| */ |
| public OutEdges<I, E> getNewEdges() { |
| return newEdges; |
| } |
| |
| /** |
| * Get the iterator over the old edges data structure. |
| * |
| * @return Old edges iterator |
| */ |
| public Iterator<Edge<I, E>> getOldEdgesIterator() { |
| return oldEdgesIterator; |
| } |
| |
| /** |
| * Get the last edge returned by the mutable iterator. |
| * |
| * @return Last edge iterated on |
| */ |
| public MutableEdge<I, E> getCurrentEdge() { |
| return currentEdge; |
| } |
| |
| /** |
| * Set the last edge returned by the mutable iterator. |
| * |
| * @param edge Last edge iterated on |
| */ |
| public void setCurrentEdge(MutableEdge<I, E> edge) { |
| currentEdge = edge; |
| } |
| |
| @Override |
| public void initialize(Iterable<Edge<I, E>> edges) { |
| throw new IllegalStateException("initialize: MutableEdgesWrapper should " + |
| "never be initialized."); |
| } |
| |
| @Override |
| public void initialize(int capacity) { |
| throw new IllegalStateException("initialize: MutableEdgesWrapper should " + |
| "never be initialized."); |
| } |
| |
| @Override |
| public void initialize() { |
| throw new IllegalStateException("initialize: MutableEdgesWrapper should " + |
| "never be initialized."); |
| } |
| |
| @Override |
| public void add(Edge<I, E> edge) { |
| unwrap().add(edge); |
| } |
| |
| @Override |
| public void remove(I targetVertexId) { |
| unwrap().remove(targetVertexId); |
| } |
| |
| @Override |
| public int size() { |
| return unwrap().size(); |
| } |
| |
| @Override |
| public Iterator<Edge<I, E>> iterator() { |
| return unwrap().iterator(); |
| } |
| |
| @Override |
| public void write(DataOutput out) throws IOException { |
| throw new IllegalStateException("write: MutableEdgesWrapper should " + |
| "never be serialized."); |
| } |
| |
| @Override |
| public void readFields(DataInput in) throws IOException { |
| throw new IllegalStateException("readFields: MutableEdgesWrapper should " + |
| "never be deserialized."); |
| } |
| } |