| /* |
| * 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 com.google.common.collect.Maps; |
| 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.Collection; |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.Map; |
| |
| /** |
| * {@link OutEdges} implementation backed by a {@link HashMap}. |
| * Parallel edges are not allowed. |
| * Note: this implementation is optimized for fast random access and mutations, |
| * but uses more space. |
| * |
| * @param <I> Vertex id |
| * @param <E> Edge value |
| */ |
| public class HashMapEdges<I extends WritableComparable, E extends Writable> |
| extends ConfigurableOutEdges<I, E> |
| implements StrictRandomAccessOutEdges<I, E>, |
| MutableOutEdges<I, E> { |
| /** Map from target vertex id to edge value. */ |
| private HashMap<I, E> edgeMap; |
| |
| @Override |
| public void initialize(Iterable<Edge<I, E>> edges) { |
| // If the iterable is actually a collection, we can cheaply get the |
| // size and initialize the hash-map with the expected capacity. |
| if (edges instanceof Collection) { |
| initialize(((Collection<Edge<I, E>>) edges).size()); |
| } else { |
| initialize(); |
| } |
| for (Edge<I, E> edge : edges) { |
| add(edge); |
| } |
| } |
| |
| @Override |
| public void initialize(int capacity) { |
| edgeMap = Maps.newHashMapWithExpectedSize(capacity); |
| } |
| |
| @Override |
| public void initialize() { |
| edgeMap = Maps.newHashMap(); |
| } |
| |
| @Override |
| public void add(Edge<I, E> edge) { |
| edgeMap.put(edge.getTargetVertexId(), edge.getValue()); |
| } |
| |
| @Override |
| public void remove(I targetVertexId) { |
| edgeMap.remove(targetVertexId); |
| } |
| |
| @Override |
| public E getEdgeValue(I targetVertexId) { |
| return edgeMap.get(targetVertexId); |
| } |
| |
| @Override |
| public void setEdgeValue(I targetVertexId, E edgeValue) { |
| if (edgeMap.containsKey(targetVertexId)) { |
| edgeMap.put(targetVertexId, edgeValue); |
| } |
| } |
| |
| @Override |
| public int size() { |
| return edgeMap.size(); |
| } |
| |
| @Override |
| public Iterator<Edge<I, E>> iterator() { |
| // Returns an iterator that reuses objects. |
| // The downcast is fine because all concrete Edge implementations are |
| // mutable, but we only expose the mutation functionality when appropriate. |
| return (Iterator) mutableIterator(); |
| } |
| |
| @Override |
| public Iterator<MutableEdge<I, E>> mutableIterator() { |
| return new Iterator<MutableEdge<I, E>>() { |
| /** Wrapped map iterator. */ |
| private Iterator<Map.Entry<I, E>> mapIterator = |
| edgeMap.entrySet().iterator(); |
| /** Representative edge object. */ |
| private MapMutableEdge<I, E> representativeEdge = |
| new MapMutableEdge<I, E>(); |
| |
| @Override |
| public boolean hasNext() { |
| return mapIterator.hasNext(); |
| } |
| |
| @Override |
| public MutableEdge<I, E> next() { |
| representativeEdge.setEntry(mapIterator.next()); |
| return representativeEdge; |
| } |
| |
| @Override |
| public void remove() { |
| mapIterator.remove(); |
| } |
| }; |
| } |
| |
| @Override |
| public void write(DataOutput out) throws IOException { |
| out.writeInt(edgeMap.size()); |
| for (Map.Entry<I, E> entry : edgeMap.entrySet()) { |
| entry.getKey().write(out); |
| entry.getValue().write(out); |
| } |
| } |
| |
| @Override |
| public void readFields(DataInput in) throws IOException { |
| int numEdges = in.readInt(); |
| initialize(numEdges); |
| for (int i = 0; i < numEdges; ++i) { |
| I targetVertexId = getConf().createVertexId(); |
| targetVertexId.readFields(in); |
| E edgeValue = getConf().createEdgeValue(); |
| edgeValue.readFields(in); |
| edgeMap.put(targetVertexId, edgeValue); |
| } |
| } |
| } |