org.apache.hadoop.mapreduce.Counter.java Source code

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Here is the source code for org.apache.hadoop.mapreduce.Counter.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.mapreduce;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.classification.InterfaceAudience.Private;
import org.apache.hadoop.io.Writable;

/**
 * A named counter that tracks the progress of a map/reduce job.
 *
 * <p><code>Counters</code> represent global counters, defined either by the
 * Map-Reduce framework or applications. Each <code>Counter</code> is named by
 * an {@link Enum} and has a long for the value.</p>
 *
 * <p><code>Counters</code> are bunched into Groups, each comprising of
 * counters from a particular <code>Enum</code> class.
 */
@InterfaceAudience.Public
@InterfaceStability.Stable
public interface Counter extends Writable {

    /**
     * Set the display name of the counter
     * @param displayName of the counter
     * @deprecated (and no-op by default)
     */
    @Deprecated
    void setDisplayName(String displayName);

    /**
     * @return the name of the counter
     */
    String getName();

    /**
     * Get the display name of the counter.
     * @return the user facing name of the counter
     */
    String getDisplayName();

    /**
     * What is the current value of this counter?
     * @return the current value
     */
    long getValue();

    /**
     * Set this counter by the given value
     * @param value the value to set
     */
    void setValue(long value);

    /**
     * Increment this counter by the given value
     * @param incr the value to increase this counter by
     */
    void increment(long incr);

    @Private
    /**
     * Return the underlying object if this is a facade.
     * @return the undelying object.
     */
    Counter getUnderlyingCounter();
}