org.apache.tez.engine.common.shuffle.impl.InMemoryWriter.java Source code

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Here is the source code for org.apache.tez.engine.common.shuffle.impl.InMemoryWriter.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.tez.engine.common.shuffle.impl;

import java.io.DataOutputStream;
import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.io.BoundedByteArrayOutputStream;
import org.apache.hadoop.io.DataInputBuffer;
import org.apache.hadoop.io.WritableUtils;
import org.apache.tez.engine.common.sort.impl.IFile;
import org.apache.tez.engine.common.sort.impl.IFileOutputStream;
import org.apache.tez.engine.common.sort.impl.IFile.Writer;

@InterfaceAudience.Private
@InterfaceStability.Unstable
public class InMemoryWriter extends Writer {
    private static final Log LOG = LogFactory.getLog(InMemoryWriter.class);

    private DataOutputStream out;

    public InMemoryWriter(BoundedByteArrayOutputStream arrayStream) {
        super(null);
        this.out = new DataOutputStream(new IFileOutputStream(arrayStream));
    }

    public void append(Object key, Object value) throws IOException {
        throw new UnsupportedOperationException("InMemoryWriter.append(K key, V value");
    }

    public void append(DataInputBuffer key, DataInputBuffer value) throws IOException {
        int keyLength = key.getLength() - key.getPosition();
        if (keyLength < 0) {
            throw new IOException("Negative key-length not allowed: " + keyLength + " for " + key);
        }

        boolean sameKey = (key == IFile.REPEAT_KEY);

        int valueLength = value.getLength() - value.getPosition();
        if (valueLength < 0) {
            throw new IOException("Negative value-length not allowed: " + valueLength + " for " + value);
        }

        if (sameKey) {
            WritableUtils.writeVInt(out, IFile.RLE_MARKER);
            WritableUtils.writeVInt(out, valueLength);
            out.write(value.getData(), value.getPosition(), valueLength);
        } else {
            if (LOG.isDebugEnabled()) {
                LOG.debug("InMemWriter.append" + " key.data=" + key.getData() + " key.pos=" + key.getPosition()
                        + " key.len=" + key.getLength() + " val.data=" + value.getData() + " val.pos="
                        + value.getPosition() + " val.len=" + value.getLength());
            }
            WritableUtils.writeVInt(out, keyLength);
            WritableUtils.writeVInt(out, valueLength);
            out.write(key.getData(), key.getPosition(), keyLength);
            out.write(value.getData(), value.getPosition(), valueLength);
        }

    }

    public void close() throws IOException {
        // Write EOF_MARKER for key/value length
        WritableUtils.writeVInt(out, IFile.EOF_MARKER);
        WritableUtils.writeVInt(out, IFile.EOF_MARKER);

        // Close the stream
        out.close();
        out = null;
    }

}