org.apache.hama.bsp.message.io.WriteSpilledDataProcessor.java Source code

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Here is the source code for org.apache.hama.bsp.message.io.WriteSpilledDataProcessor.java

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/**
 * 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.hama.bsp.message.io;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;

/**
 * A {@link SpilledDataProcessor} that writes the spilled data to the file.
 */
public class WriteSpilledDataProcessor implements SpilledDataProcessor {

    private static final Log LOG = LogFactory.getLog(WriteSpilledDataProcessor.class);

    private FileChannel fileChannel;
    private String fileName;

    public WriteSpilledDataProcessor(String fileName) throws FileNotFoundException {
        this.fileName = fileName;
    }

    private void initializeFileChannel() {
        FileOutputStream stream;
        try {
            stream = new FileOutputStream(new File(fileName), true);
        } catch (FileNotFoundException e) {
            LOG.error("Error opening file to write spilled data.", e);
            throw new RuntimeException(e);
        }
        fileChannel = stream.getChannel();
    }

    @Override
    public boolean init(Configuration conf) {

        return true;
    }

    @Override
    public boolean handleSpilledBuffer(SpilledByteBuffer buffer) {
        try {

            if (fileChannel == null) {
                initializeFileChannel();
            }

            fileChannel.write(buffer.getByteBuffer());
            fileChannel.force(true);
            return true;
        } catch (IOException e) {
            LOG.error("Error writing to file:" + fileName, e);
        }
        return false;
    }

    @Override
    public boolean close() {
        try {
            fileChannel.close();
        } catch (IOException e) {
            LOG.error("Error writing to file:" + fileName, e);
        }
        return true;
    }

}