| /* |
| * 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.util; |
| |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.api.Context.OperatorContext; |
| import com.datatorrent.api.Operator.Unifier; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * This unifier counts the number of times it consumes an input tuple within each application window. |
| * At the end of each window the tuples and their counts are emitted as a map. |
| * <p> |
| * The processing is done with sticky key partitioning, i.e. each one key belongs only to one partition. |
| * </p> |
| * @displayName Unifier Count Occur Key |
| * @category Algorithmic |
| * @tags numeric |
| * @since 0.3.3 |
| */ |
| public class UnifierCountOccurKey<K> implements Unifier<KeyValPair<K, Integer>> |
| { |
| /** |
| * Key/Occurrence map used for unifying key/occurrence values. |
| */ |
| private HashMap<K, Integer> counts = new HashMap<K, Integer>(); |
| |
| /** |
| * Key/occurrence value pair output port. |
| */ |
| public final transient DefaultOutputPort<KeyValPair<K, Integer>> outport = new DefaultOutputPort<KeyValPair<K, Integer>>(); |
| |
| /** |
| * combines the tuple into a single final tuple which is emitted in endWindow |
| * This is a merge metric for operators that use sticky key partition |
| * @param tuple incoming tuple from a partition |
| */ |
| @Override |
| public void process(KeyValPair<K, Integer> tuple) |
| { |
| if (counts.containsKey(tuple.getKey())) { |
| Integer val = (Integer)counts.remove(tuple.getKey()); |
| counts.put(tuple.getKey(), val + tuple.getValue()); |
| } else { |
| counts.put(tuple.getKey(), tuple.getValue()); |
| } |
| } |
| |
| /** |
| * empty |
| * @param windowId |
| */ |
| @Override |
| public void beginWindow(long windowId) |
| { |
| } |
| |
| |
| /** |
| * emits count sum if it is not empty |
| */ |
| @Override |
| public void endWindow() |
| { |
| if (!counts.isEmpty()) { |
| for (Map.Entry<K, Integer> entry : counts.entrySet()) { |
| outport.emit(new KeyValPair<K, Integer>(entry.getKey(), entry.getValue())); |
| } |
| } |
| counts = new HashMap<K, Integer>(); |
| } |
| |
| /** |
| * a no-op |
| * @param context |
| */ |
| @Override |
| public void setup(OperatorContext context) |
| { |
| } |
| |
| /** |
| * a noop |
| */ |
| @Override |
| public void teardown() |
| { |
| } |
| } |