webhcat/svr/src/main/java/org/apache/hcatalog/templeton/tool/NullRecordReader.java

/**
 * 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.hcatalog.templeton.tool;

import java.io.IOException;

import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;

/**
 * An empty record reader.
 */
public class NullRecordReader
    extends RecordReader<NullWritable, NullWritable> {
    @Override
    public void initialize(InputSplit genericSplit, TaskAttemptContext context)
        throws IOException {
    }

    @Override
    public void close() throws IOException {
    }

    @Override
    public NullWritable getCurrentKey() {
        return NullWritable.get();
    }

    @Override
    public NullWritable getCurrentValue() {
        return NullWritable.get();
    }

    @Override
    public float getProgress() {
        return 1.0f;
    }

    @Override
    public boolean nextKeyValue() throws IOException {
        return false;
    }
}