/*

  * 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.partition;

 import org.apache.giraph.conf.ImmutableClassesGiraphConfiguration;

 import org.apache.giraph.graph.VertexValueCombiner;

 import org.apache.giraph.utils.VertexIterator;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 import org.apache.hadoop.util.Progressable;

 import java.io.DataInput;

 import java.io.DataOutput;

 import java.io.IOException;

 /**

  * Basic partition class for other partitions to extend. Holds partition id,

  * configuration, progressable and partition context

  *

  * @param <I> Vertex index value

  * @param <V> Vertex value

  * @param <E> Edge value

  */

 public abstract class BasicPartition<I extends WritableComparable,

     V extends Writable, E extends Writable>

     implements Partition<I, V, E> {

   /** Configuration from the worker */

   private ImmutableClassesGiraphConfiguration<I, V, E> conf;

   /** Partition id */

   private int id;

   /** Context used to report progress */

   private Progressable progressable;

   /** Vertex value combiner */

   private VertexValueCombiner<V> vertexValueCombiner;

   @Override

   public void initialize(int partitionId, Progressable progressable) {

     setId(partitionId);

     setProgressable(progressable);

     vertexValueCombiner = conf.createVertexValueCombiner();

   }

   @Override

   public void setConf(

       ImmutableClassesGiraphConfiguration<I, V, E> configuration) {

     conf = configuration;

   }

   @Override

   public ImmutableClassesGiraphConfiguration<I, V, E> getConf() {

     return conf;

   }

   @Override

   public int getId() {

     return id;

   }

   @Override

   public void setId(int id) {

     this.id = id;

   }

   @Override

   public void progress() {

     if (progressable != null) {

       progressable.progress();

     }

   }

   @Override

   public void setProgressable(Progressable progressable) {

     this.progressable = progressable;

   }

   public VertexValueCombiner<V> getVertexValueCombiner() {

     return vertexValueCombiner;

   }

   @Override

   public void addPartitionVertices(VertexIterator<I, V, E> vertexIterator) {

     while (vertexIterator.hasNext()) {

       vertexIterator.next();

       // Release the vertex if it was put, otherwise reuse as an optimization

       if (putOrCombine(vertexIterator.getVertex())) {

         vertexIterator.releaseVertex();

       }

     }

   }

   @Override

   public void write(DataOutput output) throws IOException {

     output.writeInt(id);

   }

   @Override

   public void readFields(DataInput input) throws IOException {

     id = input.readInt();

   }

 }