eu.stratosphere.nephele.streaming.message.qosreport.EdgeLatency.java Source code

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/***********************************************************************************************************************
 *
 * Copyright (C) 2010 by the Stratosphere project (http://stratosphere.eu)
 *
 * Licensed 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 eu.stratosphere.nephele.streaming.message.qosreport;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.apache.commons.lang3.builder.HashCodeBuilder;

import eu.stratosphere.nephele.streaming.taskmanager.qosmodel.QosReporterID;

/**
 * This class stores information about the latency of a specific edge (channel).
 * 
 * @author warneke, Bjoern Lohrmann
 */
public final class EdgeLatency extends AbstractQosReportRecord {

    /**
     * The {@link QosReporterID} of the reporter that sends the channel.
     */
    private QosReporterID.Edge reporterID;

    private int counter;

    /**
     * The channel latency in milliseconds
     */
    private double edgeLatency;

    /**
     * Constructs a new path latency object.
     * 
     * @param sourceChannelID
     *            {@link ChannelID} representing the source end of the channel
     * @param channelLatency
     *            the channel latency in milliseconds
     */
    public EdgeLatency(QosReporterID.Edge reporterID, double edgeLatency) {

        this.reporterID = reporterID;
        this.edgeLatency = edgeLatency;
        this.counter = 1;
    }

    /**
     * Default constructor for the deserialization of the object.
     */
    public EdgeLatency() {
    }

    public void add(EdgeLatency other) {
        this.counter++;
        this.edgeLatency += other.getEdgeLatency();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void write(final DataOutput out) throws IOException {
        this.reporterID.write(out);
        out.writeDouble(this.getEdgeLatency());
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void read(final DataInput in) throws IOException {
        this.reporterID = new QosReporterID.Edge();
        this.reporterID.read(in);
        this.edgeLatency = in.readDouble();
        this.counter = 1;
    }

    /**
     * Returns the reporterID.
     * 
     * @return the reporterID
     */
    public QosReporterID.Edge getReporterID() {
        return this.reporterID;
    }

    /**
     * Returns the channel latency in milliseconds.
     * 
     * @return the channel latency in milliseconds
     */
    public double getEdgeLatency() {

        return this.edgeLatency / this.counter;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString() {

        final StringBuilder str = new StringBuilder();
        str.append(this.reporterID.toString());
        str.append(": ");
        str.append(this.edgeLatency);

        return str.toString();
    }

    @Override
    public boolean equals(Object otherObj) {
        boolean isEqual = false;
        if (otherObj instanceof EdgeLatency) {
            EdgeLatency other = (EdgeLatency) otherObj;
            isEqual = other.reporterID.equals(this.reporterID) && other.getEdgeLatency() == this.getEdgeLatency();
        }

        return isEqual;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        return new HashCodeBuilder().append(this.edgeLatency).append(this.reporterID).toHashCode();
    }
}