org.apache.crunch.impl.mem.CountersWrapper.java Source code

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Here is the source code for org.apache.crunch.impl.mem.CountersWrapper.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.crunch.impl.mem;

import com.google.common.base.Function;
import com.google.common.collect.Iterables;
import com.google.common.collect.Iterators;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import org.apache.hadoop.mapreduce.Counter;
import org.apache.hadoop.mapreduce.CounterGroup;
import org.apache.hadoop.mapreduce.Counters;

import javax.annotation.Nullable;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

class CountersWrapper extends Counters {

    private Counters active;
    private final Map<String, Map<String, Counter>> lookupCache = Maps.newHashMap();
    private Set<Counters> allCounters = Sets.newHashSet();

    CountersWrapper() {
        this.active = new Counters();
        allCounters.add(active);
    }

    CountersWrapper(org.apache.hadoop.mapred.Counters counters) {
        this.active = new Counters(counters);
        allCounters.add(active);
    }

    @Override
    public Counter findCounter(String groupName, String counterName) {
        Map<String, Counter> c = lookupCache.get(groupName);
        if (c == null) {
            c = Maps.newHashMap();
            lookupCache.put(groupName, c);
        }
        Counter counter = c.get(counterName);
        if (counter == null) {
            try {
                counter = active.findCounter(groupName, counterName);
            } catch (Exception e) {
                // Recover from this by creating a new active instance
                active = new Counters();
                allCounters.add(active);
                counter = active.findCounter(groupName, counterName);
            }
            c.put(counterName, counter);
        }
        return counter;
    }

    @Override
    public synchronized Counter findCounter(Enum<?> key) {
        return findCounter(key.getClass().getName(), key.name());
    }

    @Override
    public synchronized Collection<String> getGroupNames() {
        return lookupCache.keySet();
    }

    @Override
    public Iterator<CounterGroup> iterator() {
        return Iterators.concat(Iterables.transform(allCounters, new Function<Counters, Iterator<CounterGroup>>() {
            @Override
            public Iterator<CounterGroup> apply(@Nullable Counters input) {
                return input.iterator();
            }
        }).iterator());
    }

    @Override
    public synchronized CounterGroup getGroup(String groupName) {
        if (allCounters.size() == 1) {
            return active.getGroup(groupName);
        } else {
            throw new UnsupportedOperationException(
                    "CounterWrapper cannot return CounterGroup when there are too many Counters");
        }
    }

    public synchronized void write(DataOutput out) throws IOException {
        throw new UnsupportedOperationException("CountersWrapper may not be written");
    }

    public synchronized void readFields(DataInput in) throws IOException {
        throw new UnsupportedOperationException("CountersWrapper may not be read");
    }

    @Override
    public synchronized int countCounters() {
        int cntrs = 0;
        for (Counters c : allCounters) {
            cntrs += c.countCounters();
        }
        return cntrs;
    }

    public synchronized void incrAllCounters(Counters other) {
        for (CounterGroup cg : other) {
            for (Counter c : cg) {
                findCounter(cg.getName(), c.getName()).increment(c.getValue());
            }
        }
    }
}