| /** |
| * 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.math; |
| |
| import com.datatorrent.api.DefaultInputPort; |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.common.util.Pair; |
| import com.datatorrent.lib.util.BaseNumberValueOperator; |
| |
| /** |
| * |
| * Emits the average of values at the end of window. |
| * <p> |
| * This is an end window operator. <br> |
| * <b>Ports</b>:<br> |
| * <b>data</b>: expects V extends Number<br> |
| * <b>average</b>: emits V extends Number<br> |
| * <br> |
| * <br> |
| * <b>Properties</b>: None<br> |
| * <b>Specific compile time checks</b>: None<br> |
| * <b>Specific run time checks</b>: None<br> |
| * <p> |
| * @displayName Average |
| * @category Math |
| * @tags average, numeric, end window |
| * @since 0.3.3 |
| */ |
| public class Average<V extends Number> extends BaseNumberValueOperator<V> |
| { |
| /** |
| * Input port that takes a number. |
| */ |
| public final transient DefaultInputPort<V> data = new DefaultInputPort<V>() |
| { |
| /** |
| * Computes sum and count with each tuple |
| */ |
| @Override |
| public void process(V tuple) |
| { |
| sums += tuple.doubleValue(); |
| counts++; |
| } |
| }; |
| |
| /** |
| * Output port that emits average as a number. |
| */ |
| public final transient DefaultOutputPort<Pair<V,Long>> average = new DefaultOutputPort<Pair<V, Long>>() |
| { |
| @Override |
| public Unifier<Pair<V, Long>> getUnifier() |
| { |
| return new AvgUnifier<V>(); |
| } |
| }; |
| |
| protected double sums = 0; |
| protected long counts = 0; |
| |
| /** |
| * Emit average. |
| */ |
| @Override |
| public void endWindow() |
| { |
| // May want to send out only if count != 0 |
| |
| if (counts != 0) { |
| Pair<V,Long> pair = new Pair<>(getAverage(),counts); |
| average.emit(pair); |
| } |
| |
| sums = 0; |
| counts = 0; |
| } |
| |
| public static class AvgUnifier<V extends Number> extends Average<V> implements Unifier<Pair<V, Long>> |
| { |
| |
| @Override |
| public void process(Pair<V, Long> pair) |
| { |
| sums += pair.getFirst().doubleValue() * pair.getSecond(); |
| counts += pair.getSecond(); |
| } |
| } |
| |
| /** |
| * Calculate average based on number type. |
| */ |
| @SuppressWarnings("unchecked") |
| public V getAverage() |
| { |
| if (counts == 0) { |
| return null; |
| } |
| V num = getValue(sums); |
| Number val; |
| switch (getType()) { |
| case DOUBLE: |
| val = new Double(num.doubleValue() / counts); |
| break; |
| case INTEGER: |
| int icount = (int)(num.intValue() / counts); |
| val = new Integer(icount); |
| break; |
| case FLOAT: |
| val = new Float(num.floatValue() / counts); |
| break; |
| case LONG: |
| val = new Long(num.longValue() / counts); |
| break; |
| case SHORT: |
| short scount = (short)(num.shortValue() / counts); |
| val = new Short(scount); |
| break; |
| default: |
| val = new Double(num.doubleValue() / counts); |
| break; |
| } |
| return (V)val; |
| } |
| } |