org.apache.hadoop.mapred.nativetask.handlers.NativeMapTask.java Source code

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Here is the source code for org.apache.hadoop.mapred.nativetask.handlers.NativeMapTask.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.hadoop.mapred.nativetask.handlers;

import java.io.Closeable;
import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapred.TaskAttemptID;
import org.apache.hadoop.mapred.nativetask.Command;
import org.apache.hadoop.mapred.nativetask.CommandDispatcher;
import org.apache.hadoop.mapred.nativetask.DataChannel;
import org.apache.hadoop.mapred.nativetask.INativeHandler;
import org.apache.hadoop.mapred.nativetask.NativeBatchProcessor;
import org.apache.hadoop.mapred.nativetask.util.NativeTaskOutput;
import org.apache.hadoop.mapred.nativetask.util.OutputUtil;
import org.apache.hadoop.mapred.nativetask.util.ReadWriteBuffer;

/**
 * 
 * Full Native Map Task
 */
public class NativeMapTask implements CommandDispatcher, Closeable {
    public static String NAME = "NativeTask.MMapTaskHandler";
    private static final Log LOG = LogFactory.getLog(NativeMapTask.class);
    public static Command GET_OUTPUT_PATH = new Command(100, "GET_OUTPUT_PATH");
    public static Command GET_OUTPUT_INDEX_PATH = new Command(101, "GET_OUTPUT_INDEX_PATH");
    public static Command GET_SPILL_PATH = new Command(102, "GET_SPILL_PATH");

    public static Command RUN = new Command(3, "RUN");

    private int spillNumber = 0;
    private final INativeHandler nativeHandler;
    private boolean closed = false;
    private NativeTaskOutput output;

    public static NativeMapTask create(Configuration conf, TaskAttemptID taskAttemptID) throws IOException {
        final INativeHandler nativeHandler = NativeBatchProcessor.create(NAME, conf, DataChannel.NONE);
        return new NativeMapTask(conf, nativeHandler, taskAttemptID);
    }

    public NativeMapTask(Configuration conf, INativeHandler nativeHandler, TaskAttemptID taskAttemptID)
            throws IOException {
        if (null == taskAttemptID) {
            this.output = OutputUtil.createNativeTaskOutput(conf, "");
        } else {
            this.output = OutputUtil.createNativeTaskOutput(conf, taskAttemptID.toString());
        }
        this.nativeHandler = nativeHandler;
    }

    @Override
    public ReadWriteBuffer onCall(Command command, ReadWriteBuffer parameter) throws IOException {
        Path p = null;

        if (null == command) {
            return null;
        }

        if (command.equals(GET_OUTPUT_PATH)) {
            p = output.getOutputFileForWrite(-1);
        } else if (command.equals(GET_OUTPUT_INDEX_PATH)) {
            p = output.getOutputIndexFileForWrite(-1);
        } else if (command.equals(GET_SPILL_PATH)) {
            p = output.getSpillFileForWrite(spillNumber++, -1);
        } else {
            throw new IOException("Illegal command: " + command.toString());
        }

        if (p != null) {
            final ReadWriteBuffer result = new ReadWriteBuffer();
            result.writeString(p.toUri().getPath());
            return result;
        } else {
            throw new IOException("MapOutputFile can't allocate spill/output file");
        }
    }

    public void run() throws IOException {
        nativeHandler.call(RUN, null);
    }

    @Override
    public void close() throws IOException {
        if (closed) {
            return;
        }
        nativeHandler.close();
        closed = true;
    }
}