/**
 * 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.godhuli.rhipe;

import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.input.SequenceFileRecordReader;

import java.io.IOException;

/**
 * This class converts the input keys and values to their String forms by
 * calling toString() method. This class to SequenceFileAsTextInputFormat
 * class is as LineRecordReader class to TextInputFormat class.
 */
public class SequenceFileAsRHTextRecordReader extends RecordReader<RHText, RHText> {

    private final SequenceFileRecordReader<WritableComparable<?>, Writable> sequenceFileRecordReader;

    private RHText key;
    private RHText value;

    public SequenceFileAsRHTextRecordReader() throws IOException {
        sequenceFileRecordReader = new SequenceFileRecordReader<WritableComparable<?>, Writable>();
    }

    public void initialize(final InputSplit split, final TaskAttemptContext context) throws IOException, InterruptedException {
        sequenceFileRecordReader.initialize(split, context);
    }

    @Override
    public RHText getCurrentKey() throws IOException, InterruptedException {
        return key;
    }

    @Override
    public RHText getCurrentValue() throws IOException, InterruptedException {
        return value;
    }

    /**
     * Read key/value pair in a line.
     */
    public synchronized boolean nextKeyValue() throws IOException, InterruptedException {
        if (!sequenceFileRecordReader.nextKeyValue()) {
            return false;
        }
        if (key == null) {
            key = new RHText();
        }
        if (value == null) {
            value = new RHText();
        }
        key.setAndFinis(sequenceFileRecordReader.getCurrentKey().toString());
        value.setAndFinis(sequenceFileRecordReader.getCurrentValue().toString());
        return true;
    }

    public float getProgress() throws IOException, InterruptedException {
        return sequenceFileRecordReader.getProgress();
    }

    public synchronized void close() throws IOException {
        sequenceFileRecordReader.close();
    }
}
