| /** |
| * 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.window.accumulation; |
| |
| import java.util.Comparator; |
| import org.apache.apex.malhar.lib.window.Accumulation; |
| |
| /** |
| * Max accumulation. |
| * |
| * @since 3.5.0 |
| */ |
| public class Max<T> implements Accumulation<T, T, T> |
| { |
| |
| Comparator<T> comparator; |
| |
| public void setComparator(Comparator<T> comparator) |
| { |
| this.comparator = comparator; |
| } |
| |
| @Override |
| public T defaultAccumulatedValue() |
| { |
| return null; |
| } |
| |
| @Override |
| public T accumulate(T accumulatedValue, T input) |
| { |
| if (accumulatedValue == null) { |
| return input; |
| } else if (comparator != null) { |
| return (comparator.compare(input, accumulatedValue) > 0) ? input : accumulatedValue; |
| } else if (input instanceof Comparable) { |
| return (((Comparable)input).compareTo(accumulatedValue) > 0) ? input : accumulatedValue; |
| } else { |
| throw new RuntimeException("Tuple cannot be compared"); |
| } |
| } |
| |
| @Override |
| public T merge(T accumulatedValue1, T accumulatedValue2) |
| { |
| return accumulate(accumulatedValue1, accumulatedValue2); |
| } |
| |
| @Override |
| public T getOutput(T accumulatedValue) |
| { |
| return accumulatedValue; |
| } |
| |
| @Override |
| public T getRetraction(T value) |
| { |
| // TODO: Need to add implementation for retraction. |
| return null; |
| } |
| } |