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

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Here is the source code for org.apache.hadoop.mapreduce.Counters.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.mapreduce.counters.Limits;
import org.apache.hadoop.mapreduce.counters.GenericCounter;
import org.apache.hadoop.mapreduce.counters.AbstractCounterGroup;
import org.apache.hadoop.mapreduce.counters.CounterGroupBase;
import org.apache.hadoop.mapreduce.counters.FileSystemCounterGroup;
import org.apache.hadoop.mapreduce.counters.AbstractCounters;
import org.apache.hadoop.mapreduce.counters.CounterGroupFactory;
import org.apache.hadoop.mapreduce.counters.FrameworkCounterGroup;

/**
 * <p><code>Counters</code> holds per job/task counters, defined either by the
 * Map-Reduce framework or applications. Each <code>Counter</code> can be of
 * any {@link Enum} type.</p>
 *
 * <p><code>Counters</code> are bunched into {@link CounterGroup}s, each
 * comprising of counters from a particular <code>Enum</code> class.
 */
@InterfaceAudience.Public
@InterfaceStability.Stable
public class Counters extends AbstractCounters<Counter, CounterGroup> {

    // Mix framework group implementation into CounterGroup interface
    private static class FrameworkGroupImpl<T extends Enum<T>> extends FrameworkCounterGroup<T, Counter>
            implements CounterGroup {

        FrameworkGroupImpl(Class<T> cls) {
            super(cls);
        }

        @Override
        protected FrameworkCounter<T> newCounter(T key) {
            return new FrameworkCounter<T>(key, getName());
        }

        @Override
        public CounterGroupBase<Counter> getUnderlyingGroup() {
            return this;
        }
    }

    // Mix generic group implementation into CounterGroup interface
    // and provide some mandatory group factory methods.
    private static class GenericGroup extends AbstractCounterGroup<Counter> implements CounterGroup {

        GenericGroup(String name, String displayName, Limits limits) {
            super(name, displayName, limits);
        }

        @Override
        protected Counter newCounter(String name, String displayName, long value) {
            return new GenericCounter(name, displayName, value);
        }

        @Override
        protected Counter newCounter() {
            return new GenericCounter();
        }

        @Override
        public CounterGroupBase<Counter> getUnderlyingGroup() {
            return this;
        }
    }

    // Mix file system group implementation into the CounterGroup interface
    private static class FileSystemGroup extends FileSystemCounterGroup<Counter> implements CounterGroup {

        @Override
        protected Counter newCounter(String scheme, FileSystemCounter key) {
            return new FSCounter(scheme, key);
        }

        @Override
        public CounterGroupBase<Counter> getUnderlyingGroup() {
            return this;
        }
    }

    /**
     * Provide factory methods for counter group factory implementation.
     * See also the GroupFactory in
     *  {@link org.apache.hadoop.mapred.Counters mapred.Counters}
     */
    private static class GroupFactory extends CounterGroupFactory<Counter, CounterGroup> {

        @Override
        protected <T extends Enum<T>> FrameworkGroupFactory<CounterGroup> newFrameworkGroupFactory(
                final Class<T> cls) {
            return new FrameworkGroupFactory<CounterGroup>() {
                @Override
                public CounterGroup newGroup(String name) {
                    return new FrameworkGroupImpl<T>(cls); // impl in this package
                }
            };
        }

        @Override
        protected CounterGroup newGenericGroup(String name, String displayName, Limits limits) {
            return new GenericGroup(name, displayName, limits);
        }

        @Override
        protected CounterGroup newFileSystemGroup() {
            return new FileSystemGroup();
        }
    }

    private static final GroupFactory groupFactory = new GroupFactory();

    /**
     * Default constructor
     */
    public Counters() {
        super(groupFactory);
    }

    /**
     * Construct the Counters object from the another counters object
     * @param <C> the type of counter
     * @param <G> the type of counter group
     * @param counters the old counters object
     */
    public <C extends Counter, G extends CounterGroupBase<C>> Counters(AbstractCounters<C, G> counters) {
        super(counters, groupFactory);
    }
}