/*
 * 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.examples;

import org.apache.giraph.bsp.BspInputSplit;
import org.apache.giraph.conf.BooleanConfOption;
import org.apache.giraph.conf.LongConfOption;
import org.apache.giraph.io.VertexReader;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.TaskAttemptContext;

import java.io.IOException;

/**
 * Used by GeneratedVertexInputFormat to read some generated data
 *
 * @param <I> Vertex index value
 * @param <V> Vertex value
 * @param <E> Edge value
 */
@SuppressWarnings("rawtypes")
public abstract class GeneratedVertexReader<
    I extends WritableComparable, V extends Writable,
    E extends Writable>
    extends VertexReader<I, V, E> {
  /** Vertices produced by this reader */
  public static final LongConfOption READER_VERTICES =
      new LongConfOption("GeneratedVertexReader.reader_vertices", 10,
          "Vertices produced by this reader");
  /** Reverse the order of the vertices? */
  public static final BooleanConfOption REVERSE_ID_ORDER =
      new BooleanConfOption("GeneratedVertexReader.reverseIdOrder", false,
          "Reverse the order of the vertices?");
  /** Records read so far */
  protected long recordsRead = 0;
  /** Total records to read (on this split alone) */
  protected long totalRecords = 0;
  /** The input split from initialize(). */
  protected BspInputSplit inputSplit = null;
  /** Reverse the id order? */
  protected boolean reverseIdOrder;

  /**
   * Default constructor for reflection.
   */
  public GeneratedVertexReader() {
  }

  @Override
  public final void initialize(InputSplit inputSplit,
      TaskAttemptContext context) throws IOException {
    totalRecords = GeneratedVertexReader.READER_VERTICES.get(getConf());
    reverseIdOrder = GeneratedVertexReader.REVERSE_ID_ORDER.get(getConf());
    this.inputSplit = (BspInputSplit) inputSplit;
  }

  @Override
  public void close() throws IOException {
  }

  @Override
  public final float getProgress() throws IOException {
    return recordsRead * 100.0f / totalRecords;
  }
}