com.datatorrent.lib.math.CountMap.java Source code

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Here is the source code for com.datatorrent.lib.math.CountMap.java

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/*
 * Copyright (c) 2013 DataTorrent, Inc. ALL Rights Reserved.
 *
 * 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 com.datatorrent.lib.math;

import java.util.HashMap;
import java.util.Map;

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

import com.datatorrent.api.DefaultInputPort;
import com.datatorrent.api.DefaultOutputPort;
import com.datatorrent.api.annotation.InputPortFieldAnnotation;
import com.datatorrent.api.annotation.OutputPortFieldAnnotation;
import com.datatorrent.lib.util.BaseKeyValueOperator;
import com.datatorrent.lib.util.UnifierHashMapInteger;

/**
 * Operator aggregates <key,occurrence> count in map from <key,value> map input port.
 * <p>
 * Emits the count of occurrences of each key at the end of window. <br>
 * <br>
 * StateFull : Yes, each key occurrence are counted till end windows is seen. <br>
 * Partitions : Yes, hash sum unifier on output port. <br>
 * <br>
 * <b>Ports</b>:<br>
 * <b>data</b>: expects Map&lt;K,V extends Number&gt;<br>
 * <b>count</b>: emits HashMap&lt;K,Integer&gt;<br>
 * <br>
 * <b>Properties</b>: <br>
 *  counts : Key occurrence aggregate map.
 * <br>
 * @displayName Count Map
 * @category Math
 * @tags count, key value, aggregate, map
 * @since 0.3.3
 */
public class CountMap<K, V> extends BaseKeyValueOperator<K, V> {
    /**
     * Aggregate key occurrence count.
     */
    protected HashMap<K, MutableInt> counts = new HashMap<K, MutableInt>();

    /**
     * Input port that takes a map of &lt;key,value&gt;. 
     */
    public final transient DefaultInputPort<Map<K, V>> data = new DefaultInputPort<Map<K, V>>() {
        /**
         * For each tuple (a HashMap of keys,val pairs) Adds the values for each
         * key.
         */
        @Override
        public void process(Map<K, V> tuple) {
            for (Map.Entry<K, V> e : tuple.entrySet()) {
                K key = e.getKey();
                MutableInt val = counts.get(key);
                if (val == null) {
                    val = new MutableInt();
                    counts.put(key, val);
                }
                val.increment();
            }
        }
    };

    /**
    * Key, occurrence value hashmap output port.
    */
    public final transient DefaultOutputPort<HashMap<K, Integer>> count = new DefaultOutputPort<HashMap<K, Integer>>() {
        @Override
        public Unifier<HashMap<K, Integer>> getUnifier() {
            return new UnifierHashMapInteger<K>();
        }
    };

    /**
     * Emits on all ports that are connected. Data is precomputed during process
     * on input port endWindow just emits it for each key Clears the internal data
     * before return
     */
    @Override
    public void endWindow() {
        HashMap<K, Integer> tuples = new HashMap<K, Integer>();
        for (Map.Entry<K, MutableInt> e : counts.entrySet()) {
            tuples.put(e.getKey(), e.getValue().intValue());
        }
        if (!tuples.isEmpty()) {
            count.emit(tuples);
        }
        clearCache();
    }

    public void clearCache() {
        counts.clear();
    }
}