| /* |
| * 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.stream; |
| |
| import com.datatorrent.api.Context.OperatorContext; |
| import com.datatorrent.api.DefaultInputPort; |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.api.Operator; |
| import com.datatorrent.api.Operator.Unifier; |
| |
| /** |
| * An implementation of Operator and Unifier that counts the number of tuples delivered to it in each window and emits the count. |
| * <p> |
| * This is a pass through operator<br> |
| * <br> |
| * <b>StateFull : Yes</b>, tuples are counted over application window. <br> |
| * <b>Partitions : Yes</b>, count is unified at output port. <br> |
| * <b>Ports</b>:<br> |
| * <b>input</b>: expects Object<br> |
| * <b>output</b>: emits Integer<br> |
| * <br> |
| * @displayName Counter |
| * @category Stream |
| * @tags integer, object, count |
| * @since 0.3.3 |
| */ |
| public class Counter implements Operator, Unifier<Integer> |
| { |
| /** |
| * Input port that takes objects to be counted in each window. |
| */ |
| public final transient DefaultInputPort<Object> input = new DefaultInputPort<Object>() |
| { |
| @Override |
| public void process(Object tuple) |
| { |
| count++; |
| } |
| |
| }; |
| |
| /** |
| * Output port that takes emits count in each window. |
| */ |
| public final transient DefaultOutputPort<Integer> output = new DefaultOutputPort<Integer>() |
| { |
| @Override |
| public Unifier<Integer> getUnifier() |
| { |
| return Counter.this; |
| } |
| |
| }; |
| |
| @Override |
| public void beginWindow(long windowId) |
| { |
| count = 0; |
| } |
| |
| @Override |
| public void process(Integer tuple) |
| { |
| count += tuple; |
| } |
| |
| @Override |
| public void endWindow() |
| { |
| output.emit(count); |
| } |
| |
| @Override |
| public void setup(OperatorContext context) |
| { |
| } |
| |
| @Override |
| public void teardown() |
| { |
| } |
| |
| private transient int count; |
| } |