/*
    * 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.worker.LocalData;
  import org.apache.hadoop.io.LongWritable;
  import org.apache.hadoop.io.Writable;
  import org.apache.log4j.Logger;
  
  /**
   * Factory for long-byte mapping based partitioners.
   *
   * @param <V> vertexValue type
   * @param <E> edgeValue type
   */
  @SuppressWarnings("unchecked")
  public class LongMappingStorePartitionerFactory<V extends Writable,
      E extends Writable> extends GraphPartitionerFactory<LongWritable, V, E> {
    /** Logger Instance */
    private static final Logger LOG = Logger.getLogger(
        LongMappingStorePartitionerFactory.class);
    /** Local Data that supplies the mapping store */
    protected LocalData<LongWritable, V, E, ? extends Writable> localData = null;
  
    @Override
    public void initialize(LocalData<LongWritable, V, E,
      ? extends Writable> localData) {
      this.localData = localData;
      LOG.info("Initializing LongMappingStorePartitionerFactory with localData");
    }
  
    @Override
    public int getPartition(LongWritable id, int partitionCount,
      int workerCount) {
      return localData.getMappingStoreOps().getPartition(id,
          partitionCount, workerCount);
    }
  
    @Override
    public int getWorker(int partition, int partitionCount, int workerCount) {
      int numRows = partitionCount / workerCount;
      numRows = (numRows * workerCount == partitionCount) ? numRows : numRows + 1;
      return partition / numRows;
    }
  }