| /** |
| * 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.stream; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| |
| /** |
| * |
| * An implementation of AbstractAggregator that creates an ArrayList tuple from incoming tuples. |
| * <p> |
| * The size of the ArrayList before it is emitted is determined by property \"size\". If size == 0 |
| * then the ArrayList (if not empty) is emitted in the endWindow call. Is size is specified then the ArrayList is emitted as soon as the size is |
| * reached as part of process(tuple), and no emit happens in endWindow. For size != 0, the operator is statefull.<p> |
| * <br> |
| * <b>Port</b>:<br> |
| * <b>input</b>: expects T<br> |
| * <b>output</b>: emits ArrayList<T><br> |
| * <br> |
| * <b>Properties</b>:<br> |
| * <b>size</b>: The size of ArrayList. If specified the ArrayList is emitted the moment it reaches this size. |
| * If 0, the ArrayList is emitted in endWindow call. Default value is 0, </br> |
| * <br> |
| * @displayName Array List Aggregator |
| * @category Stream Manipulators |
| * @tags list, aggregate, collection |
| * @param <T> Type of elements in the collection.<br> |
| * @since 0.3.3 |
| */ |
| public class ArrayListAggregator<T> extends AbstractAggregator<T> |
| { |
| @Override |
| public Collection<T> getNewCollection(int size) |
| { |
| return new ArrayList<T>(size); |
| } |
| } |
