| /** |
| * 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.util; |
| |
| import com.datatorrent.api.Context.OperatorContext; |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.api.Operator.Unifier; |
| |
| /** |
| * This unifier consumes numbers, and emits their sum at the end of each application window. |
| * <p> |
| * This unifier uses round robin partitioning. |
| * </p> |
| * @displayName Unifier Sum Number |
| * @category Algorithmic |
| * @tags numeric |
| * @since 0.3.2 |
| */ |
| public class UnifierSumNumber<V extends Number> extends BaseNumberValueOperator<V> implements Unifier<V> |
| { |
| private Double result = 0.0; |
| private boolean doEmit = false; |
| /** |
| * This is the output port which emits a sum. |
| */ |
| public final transient DefaultOutputPort<V> mergedport = new DefaultOutputPort<V>(); |
| |
| /** |
| * Adds tuple with result so far |
| * |
| * @param tuple incoming tuple from a partition |
| */ |
| @Override |
| public void process(V tuple) |
| { |
| result += tuple.doubleValue(); |
| doEmit = true; |
| } |
| |
| /** |
| * emits the result, and resets it |
| */ |
| @Override |
| public void endWindow() |
| { |
| if (doEmit) { |
| mergedport.emit(getValue(result)); |
| result = 0.0; |
| doEmit = false; |
| } |
| } |
| |
| /** |
| * a no-op |
| * |
| * @param context |
| */ |
| @Override |
| public void setup(OperatorContext context) |
| { |
| } |
| |
| /** |
| * a noop |
| */ |
| @Override |
| public void teardown() |
| { |
| } |
| } |