org.apache.giraph.comm.aggregators.AggregatorOutputStream.java Source code

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Here is the source code for org.apache.giraph.comm.aggregators.AggregatorOutputStream.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.giraph.comm.aggregators;

import org.apache.giraph.aggregators.Aggregator;
import org.apache.hadoop.io.Writable;

import java.io.IOException;

/**
 * Implementation of {@link CountingOutputStream} which allows writing of
 * aggregators in the form of triple (name, classname, value)
 */
public class AggregatorOutputStream extends CountingOutputStream {
    /**
     * Write aggregator to the stream and increment internal counter
     *
     * @param aggregatorName Name of the aggregator
     * @param aggregatorClass Class of aggregator
     * @param aggregatedValue Value of aggregator
     * @return Number of bytes occupied by the stream
     * @throws IOException
     */
    public int addAggregator(String aggregatorName, Class<? extends Aggregator> aggregatorClass,
            Writable aggregatedValue) throws IOException {
        incrementCounter();
        dataOutput.writeUTF(aggregatorName);
        dataOutput.writeUTF(aggregatorClass.getName());
        aggregatedValue.write(dataOutput);
        return getSize();
    }
}