| /** |
| * 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 com.datatorrent.lib.util; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import com.datatorrent.api.Context.OperatorContext; |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.api.Operator.Unifier; |
| |
| /** |
| * This is an abstract operator which consumes key value pairs, |
| * where the key is an object and the value is an integer. |
| * The operator emits either the largest or smallest value associated with each key at the end of each application window. |
| * <p> |
| * The processing done is done with a sticky key partition, i.e. each one key belongs only to one partition. |
| * </p> |
| * @displayName Array Hash Map Frequent |
| * @category Algorithmic |
| * @tags numeric |
| * @since 0.3.3 |
| */ |
| public class ArrayHashMapFrequent<K> implements Unifier<HashMap<K, Integer>> |
| { |
| HashMap<K, Integer> mergedTuple = new HashMap<K, Integer>(); |
| |
| /** |
| * This is the output port which emits either the largest or smallest value associated with each input tuple key. |
| */ |
| public final transient DefaultOutputPort<HashMap<K, Integer>> mergedport = new DefaultOutputPort<HashMap<K, Integer>>(); |
| |
| Integer lval; |
| boolean least = true; |
| /** |
| * combines the tuple into a single final tuple which is emitted in endWindow |
| * @param tuple incoming tuple from a partition |
| */ |
| @Override |
| public void process(HashMap<K, Integer> tuple) |
| { |
| // Tuple is HashMap<K,Integer>(1) |
| if (mergedTuple.isEmpty()) { |
| mergedTuple.putAll(tuple); |
| for (Map.Entry<K, Integer> e: tuple.entrySet()) { |
| lval = e.getValue(); |
| break; |
| } |
| } else { |
| for (Map.Entry<K, Integer> e: tuple.entrySet()) { |
| if ((least && (e.getValue() < lval)) || (!least && (e.getValue() > lval))) { |
| mergedTuple.clear(); |
| mergedTuple.put(e.getKey(), e.getValue()); |
| break; |
| } |
| } |
| } |
| } |
| |
| /** |
| * getter function for combiner doing least (true) or most (false) compare |
| * @return least flag |
| */ |
| public boolean getLeast() |
| { |
| return least; |
| } |
| |
| /** |
| * setter funtion for combiner doing least (true) or most (false) compare |
| * @param b |
| */ |
| public void setLeast(boolean b) |
| { |
| least = b; |
| } |
| |
| /** |
| * a no op |
| * @param windowId |
| */ |
| @Override |
| public void beginWindow(long windowId) |
| { |
| } |
| |
| /** |
| * emits mergedTuple on mergedport if it is not empty |
| */ |
| @Override |
| public void endWindow() |
| { |
| if (!mergedTuple.isEmpty()) { |
| mergedport.emit(mergedTuple); |
| mergedTuple = new HashMap<K, Integer>(); |
| } |
| } |
| |
| /** |
| * a no-op |
| * @param context |
| */ |
| @Override |
| public void setup(OperatorContext context) |
| { |
| } |
| |
| /** |
| * a noop |
| */ |
| @Override |
| public void teardown() |
| { |
| } |
| } |