| /** |
| * 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.storm.windowing; |
| |
| import java.util.Iterator; |
| import java.util.List; |
| import org.apache.storm.topology.base.BaseStatefulWindowedBolt; |
| |
| /** |
| * A view of events in a sliding window. |
| * |
| * @param <T> the type of event that this window contains. E.g. {@link org.apache.storm.tuple.Tuple} |
| */ |
| public interface Window<T> { |
| /** |
| * Gets the list of events in the window. |
| * <p> |
| * <b>Note: </b> If the number of tuples in windows is huge, invoking {@code get} would |
| * load all the tuples into memory and may throw an OOM exception. Use windowing with persistence ({@link |
| * BaseStatefulWindowedBolt#withPersistence()}) and {@link Window#getIter} to retrieve an iterator over the events in the window. |
| * </p> |
| * |
| * @return the list of events in the window. |
| */ |
| List<T> get(); |
| |
| /** |
| * Returns an iterator over the events in the window. |
| * <p> |
| * <b>Note: </b> This is only supported when using windowing with persistence {@link BaseStatefulWindowedBolt#withPersistence()}. |
| * </p> |
| * |
| * @return an {@link Iterator} over the events in the current window. |
| * |
| * @throws UnsupportedOperationException if not using {@link BaseStatefulWindowedBolt#withPersistence()} |
| */ |
| default Iterator<T> getIter() { |
| throw new UnsupportedOperationException("Not implemented"); |
| } |
| |
| /** |
| * Get the list of newly added events in the window since the last time the window was generated. |
| * <p> |
| * <b>Note: </b> This is not supported when using windowing with persistence ({@link BaseStatefulWindowedBolt#withPersistence()}). |
| * </p> |
| * |
| * @return the list of newly added events in the window. |
| * |
| * @throws UnsupportedOperationException if using {@link BaseStatefulWindowedBolt#withPersistence()} |
| */ |
| List<T> getNew(); |
| |
| /** |
| * Get the list of events expired from the window since the last time the window was generated. |
| * <p> |
| * <b>Note: </b> This is not supported when using windowing with persistence ({@link BaseStatefulWindowedBolt#withPersistence()}). |
| * </p> |
| * |
| * @return the list of events expired from the window. |
| * |
| * @throws UnsupportedOperationException if using {@link BaseStatefulWindowedBolt#withPersistence()} |
| */ |
| List<T> getExpired(); |
| |
| /** |
| * If processing based on event time, returns the window end time based on watermark otherwise returns the window end time based on |
| * processing time. |
| * |
| * @return the window end timestamp |
| */ |
| Long getEndTimestamp(); |
| |
| /** |
| * Returns the window start timestamp. Will return null if the window length is not based on time duration. |
| * |
| * @return the window start timestamp or null if the window length is not time based |
| */ |
| Long getStartTimestamp(); |
| } |