/*
    * 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.worker;
  
  import java.io.IOException;
  
  import org.apache.giraph.conf.ImmutableClassesGiraphConfiguration;
  import org.apache.giraph.graph.VertexEdgeCount;
  import org.apache.giraph.io.GiraphInputFormat;
  import org.apache.giraph.io.MappingInputFormat;
  import org.apache.giraph.io.MappingReader;
  import org.apache.giraph.mapping.MappingEntry;
  import org.apache.giraph.mapping.MappingStore;
  import org.apache.giraph.io.InputType;
  import org.apache.hadoop.io.Writable;
  import org.apache.hadoop.io.WritableComparable;
  import org.apache.hadoop.mapreduce.InputSplit;
  import org.apache.hadoop.mapreduce.Mapper;
  
  /**
   * Load as many mapping input splits as possible.
   * Every thread will has its own instance of WorkerClientRequestProcessor
   * to send requests.
   *
   * @param <I> vertexId type
   * @param <V> vertexValue type
   * @param <E> edgeValue type
   * @param <B> mappingTarget type
   */
  @SuppressWarnings("unchecked")
  public class MappingInputSplitsCallable<I extends WritableComparable,
    V extends Writable, E extends Writable, B extends Writable>
    extends InputSplitsCallable<I, V, E> {
    /** User supplied mappingInputFormat */
    private final MappingInputFormat<I, V, E, B> mappingInputFormat;
    /** Link to bspServiceWorker */
    private final BspServiceWorker<I, V, E> bspServiceWorker;
  
    /**
     * Constructor
     *
     * @param mappingInputFormat mappingInputFormat
     * @param context Context
     * @param configuration Configuration
     * @param bspServiceWorker bsp service worker
     * @param splitsHandler Splits handler
     */
    public MappingInputSplitsCallable(
        MappingInputFormat<I, V, E, B> mappingInputFormat,
        Mapper<?, ?, ?, ?>.Context context,
        ImmutableClassesGiraphConfiguration<I, V, E> configuration,
        BspServiceWorker<I, V, E> bspServiceWorker,
        WorkerInputSplitsHandler splitsHandler) {
      super(context, configuration, bspServiceWorker, splitsHandler);
      this.mappingInputFormat = mappingInputFormat;
      this.bspServiceWorker = bspServiceWorker;
    }
  
    @Override
    public GiraphInputFormat getInputFormat() {
      return mappingInputFormat;
    }
  
    @Override
    public InputType getInputType() {
      return InputType.MAPPING;
    }
  
    @Override
    protected VertexEdgeCount readInputSplit(InputSplit inputSplit)
      throws IOException, InterruptedException {
      MappingReader<I, V, E, B> mappingReader =
          mappingInputFormat.createMappingReader(inputSplit, context);
      mappingReader.setConf(configuration);
  
      WorkerThreadGlobalCommUsage globalCommUsage = this.bspServiceWorker
          .getAggregatorHandler().newThreadAggregatorUsage();
  
      mappingReader.initialize(inputSplit, context);
      mappingReader.setWorkerGlobalCommUsage(globalCommUsage);
  
      int entriesLoaded = 0;
      MappingStore<I, B> mappingStore =
       (MappingStore<I, B>) bspServiceWorker.getLocalData().getMappingStore();
 
     while (mappingReader.nextEntry()) {
       MappingEntry<I, B> entry = mappingReader.getCurrentEntry();
       entriesLoaded += 1;
       mappingStore.addEntry(entry.getVertexId(), entry.getMappingTarget());
     }
     return new VertexEdgeCount(0, 0, entriesLoaded);
   }
 }