tachyon.client.keyvalue.hadoop.KeyValueRecordWriter.java Source code

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Here is the source code for tachyon.client.keyvalue.hadoop.KeyValueRecordWriter.java

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/*
 * Licensed to the University of California, Berkeley 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 tachyon.client.keyvalue.hadoop;

import java.io.IOException;
import java.util.Arrays;

import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.mapred.RecordWriter;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.util.Progressable;
import org.apache.http.annotation.ThreadSafe;

import tachyon.TachyonURI;
import tachyon.client.keyvalue.KeyValueStoreWriter;
import tachyon.client.keyvalue.KeyValueStores;
import tachyon.exception.TachyonException;

/**
 * A {@link RecordWriter} to write key-value pairs into a temporary key-value store.
 */
@ThreadSafe
class KeyValueRecordWriter implements RecordWriter<BytesWritable, BytesWritable> {
    private final KeyValueStoreWriter mWriter;
    private final Progressable mProgress;

    /**
     * Constructs a new {@link KeyValueRecordWriter}.
     *
     * @param storeUri the URI for the temporary key-value store to be created by this record writer
     * @param progress the object to be used for reporting progress
     * @throws IOException when instance creation fails
     */
    public KeyValueRecordWriter(TachyonURI storeUri, Progressable progress) throws IOException {
        try {
            mWriter = KeyValueStores.Factory.create().create(storeUri);
        } catch (TachyonException e) {
            throw new IOException(e);
        }
        mProgress = progress;
    }

    @Override
    public synchronized void write(BytesWritable key, BytesWritable value) throws IOException {
        try {
            // NOTE: BytesWritable.getBytes() returns the internal byte array, whose length might not be
            // the same as BytesWritable.getLength().
            mWriter.put(Arrays.copyOf(key.getBytes(), key.getLength()),
                    Arrays.copyOf(value.getBytes(), value.getLength()));
            // Sends a progress to the job manager to inform it that the task is still running.
            mProgress.progress();
        } catch (TachyonException e) {
            throw new IOException(e);
        }
    }

    @Override
    public synchronized void close(Reporter reporter) throws IOException {
        // Completes the new store.
        mWriter.close();
    }
}