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

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Here is the source code for org.apache.hadoop.mapred.nativetask.handlers.BufferPushee.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 java.nio.ByteBuffer;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.mapred.RecordWriter;
import org.apache.hadoop.mapred.nativetask.Constants;
import org.apache.hadoop.mapred.nativetask.buffer.BufferType;
import org.apache.hadoop.mapred.nativetask.buffer.ByteBufferDataReader;
import org.apache.hadoop.mapred.nativetask.buffer.InputBuffer;
import org.apache.hadoop.mapred.nativetask.serde.KVSerializer;
import org.apache.hadoop.mapred.nativetask.util.SizedWritable;

/**
 * collect data when signaled
 */
@InterfaceAudience.Private
public class BufferPushee<OK, OV> implements Closeable {

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

    public final static int KV_HEADER_LENGTH = Constants.SIZEOF_KV_LENGTH;

    private InputBuffer asideBuffer;
    private final SizedWritable<OK> tmpOutputKey;
    private final SizedWritable<OV> tmpOutputValue;
    private RecordWriter<OK, OV> writer;
    private ByteBufferDataReader nativeReader;

    private KVSerializer<OK, OV> deserializer;
    private boolean closed = false;

    public BufferPushee(Class<OK> oKClass, Class<OV> oVClass, RecordWriter<OK, OV> writer) throws IOException {
        tmpOutputKey = new SizedWritable<OK>(oKClass);
        tmpOutputValue = new SizedWritable<OV>(oVClass);

        this.writer = writer;

        if (null != oKClass && null != oVClass) {
            this.deserializer = new KVSerializer<OK, OV>(oKClass, oVClass);
        }
        this.nativeReader = new ByteBufferDataReader(null);
    }

    public boolean collect(InputBuffer buffer) throws IOException {
        if (closed) {
            return false;
        }

        final ByteBuffer input = buffer.getByteBuffer();
        if (null != asideBuffer && asideBuffer.length() > 0) {
            if (asideBuffer.remaining() > 0) {
                final byte[] output = asideBuffer.getByteBuffer().array();
                final int write = Math.min(asideBuffer.remaining(), input.remaining());
                input.get(output, asideBuffer.position(), write);
                asideBuffer.position(asideBuffer.position() + write);
            }

            if (asideBuffer.remaining() == 0 && asideBuffer.position() > 0) {
                asideBuffer.position(0);
                write(asideBuffer);
                asideBuffer.rewind(0, 0);
            }
        }

        if (input.remaining() == 0) {
            return true;
        }

        if (input.remaining() < KV_HEADER_LENGTH) {
            throw new IOException("incomplete data, input length is: " + input.remaining());
        }
        final int position = input.position();
        final int keyLength = input.getInt();
        final int valueLength = input.getInt();
        input.position(position);
        final int kvLength = keyLength + valueLength + KV_HEADER_LENGTH;
        final int remaining = input.remaining();

        if (kvLength > remaining) {
            if (null == asideBuffer || asideBuffer.capacity() < kvLength) {
                asideBuffer = new InputBuffer(BufferType.HEAP_BUFFER, kvLength);
            }
            asideBuffer.rewind(0, kvLength);

            input.get(asideBuffer.array(), 0, remaining);
            asideBuffer.position(remaining);
        } else {
            write(buffer);
        }
        return true;
    }

    @SuppressWarnings("unchecked")
    private boolean write(InputBuffer input) throws IOException {
        if (closed) {
            return false;
        }
        int totalRead = 0;
        final int remain = input.remaining();
        this.nativeReader.reset(input);
        while (remain > totalRead) {
            final int read = deserializer.deserializeKV(nativeReader, tmpOutputKey, tmpOutputValue);
            if (read != 0) {
                totalRead += read;
                writer.write((OK) (tmpOutputKey.v), (OV) (tmpOutputValue.v));
            }
        }
        if (remain != totalRead) {
            throw new IOException("We expect to read " + remain + ", but we actually read: " + totalRead);
        }
        return true;
    }

    @Override
    public void close() throws IOException {
        if (closed) {
            return;
        }
        if (null != writer) {
            writer.close(null);
        }
        if (null != nativeReader) {
            nativeReader.close();
        }
        closed = true;
    }
}