org.apache.apex.malhar.lib.counters.BasicCounters.java Source code

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Here is the source code for org.apache.apex.malhar.lib.counters.BasicCounters.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.apex.malhar.lib.counters;

import java.io.IOException;
import java.io.Serializable;
import java.util.Collection;
import java.util.Map;

import javax.annotation.Nonnull;

import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.map.JsonSerializer;
import org.codehaus.jackson.map.SerializerProvider;
import org.codehaus.jackson.map.annotate.JsonSerialize;

import org.apache.commons.lang.mutable.Mutable;

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;

import com.datatorrent.api.Context;
import com.datatorrent.common.util.NumberAggregate;

/**
 * Implementation of basic number counters.
 *
 * @param <T> type of counter
 * @since 1.0.2
 */
@JsonSerialize(using = BasicCounters.Serializer.class)
public class BasicCounters<T extends Number & Mutable> implements Serializable {
    private final Map<Enum<?>, T> cache;
    private final Class<T> counterType;

    @SuppressWarnings("unused")
    private BasicCounters() {
        //for kryo
        cache = null;
        counterType = null;
    }

    /**
     * @param counterType type of counter
     */
    public BasicCounters(@Nonnull Class<T> counterType) {
        cache = Maps.newIdentityHashMap();
        this.counterType = counterType;
    }

    /**
     * Returns the counter associated with the key. Creates it if it doesn't exist.
     */
    @SuppressWarnings("unchecked")
    public synchronized T findCounter(Enum<?> counterKey) throws IllegalAccessException, InstantiationException {
        T counter = cache.get(counterKey);
        if (counter == null) {
            counter = counterType.newInstance();
            cache.put(counterKey, counter);
        }
        return counter;
    }

    /**
     * Returns the counter if it exists; null otherwise
     *
     * @param counterKey
     * @return counter corresponding to the counter key.
     */
    public synchronized T getCounter(Enum<?> counterKey) {
        return cache.get(counterKey);
    }

    /**
     * Sets the value of a counter.
     *
     * @param counterKey counter key.
     * @param value      new value.
     */
    public synchronized void setCounter(Enum<?> counterKey, T value) {
        cache.put(counterKey, value);
    }

    /**
     * Returns an immutable copy of all the counters.
     *
     * @return an immutable copy of the counters.
     */
    public synchronized ImmutableMap<Enum<?>, T> getCopy() {
        return ImmutableMap.copyOf(cache);
    }

    public static class Serializer extends JsonSerializer<BasicCounters<?>> implements Serializable {

        @Override
        public void serialize(BasicCounters<?> value, JsonGenerator jgen, SerializerProvider provider)
                throws IOException {
            jgen.writeObject(value.getCopy());
        }

        private static final long serialVersionUID = 201406230131L;

    }

    /**
     * Aggregates the {@link BasicCounters} of physical partitions into {@link NumberAggregate.LongAggregate}.
     *
     * @param <T> type of counter
     */
    public static class LongAggregator<T extends Number & Mutable>
            implements Context.CountersAggregator, Serializable {
        @Override
        public Object aggregate(Collection<?> objects) {
            Map<String, NumberAggregate.LongAggregate> aggregates = Maps.newHashMap();
            for (Object counter : objects) {
                if (counter instanceof BasicCounters) {
                    @SuppressWarnings("unchecked")
                    BasicCounters<T> physical = (BasicCounters<T>) counter;
                    ImmutableMap<Enum<?>, T> copy = physical.getCopy();

                    for (Map.Entry<Enum<?>, T> entry : copy.entrySet()) {

                        NumberAggregate.LongAggregate aggregate = aggregates.get(entry.getKey().name());

                        if (aggregate == null) {
                            aggregate = new NumberAggregate.LongAggregate();

                            aggregates.put(entry.getKey().name(), aggregate);
                        }
                        aggregate.addNumber(entry.getValue().longValue());
                    }
                }
            }
            return ImmutableMap.copyOf(aggregates);
        }

        private static final long serialVersionUID = 201406222203L;
    }

    /**
     * Aggregates the {@link BasicCounters} of physical partitions into {@link NumberAggregate.DoubleAggregate}.
     *
     * @param <T> type of counter
     */
    public static class DoubleAggregator<T extends Number & Mutable>
            implements Context.CountersAggregator, Serializable {
        @Override
        public Object aggregate(Collection<?> objects) {
            Map<String, NumberAggregate.DoubleAggregate> aggregates = Maps.newHashMap();
            for (Object counter : objects) {
                if (counter instanceof BasicCounters) {
                    @SuppressWarnings("unchecked")
                    BasicCounters<T> physical = (BasicCounters<T>) counter;
                    ImmutableMap<Enum<?>, T> copy = physical.getCopy();

                    for (Map.Entry<Enum<?>, T> entry : copy.entrySet()) {

                        NumberAggregate.DoubleAggregate aggregate = aggregates.get(entry.getKey().name());

                        if (aggregate == null) {
                            aggregate = new NumberAggregate.DoubleAggregate();

                            aggregates.put(entry.getKey().name(), aggregate);
                        }
                        aggregate.addNumber(entry.getValue().doubleValue());
                    }
                }
            }
            return ImmutableMap.copyOf(aggregates);
        }

        private static final long serialVersionUID = 201407011713L;
    }

    private static final long serialVersionUID = 201406230033L;
}