| /** |
| * 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; |
| |
| import java.util.Collection; |
| import java.util.Map; |
| |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| /** |
| * This interface is for storing data for session windowed streams. |
| * |
| * @param <K> The key type |
| * @param <V> The value type |
| * |
| * @since 3.5.0 |
| */ |
| @InterfaceStability.Evolving |
| public interface SessionWindowedStorage<K, V> extends WindowedStorage.WindowedKeyedStorage<K, V> |
| { |
| /** |
| * Migrate the data from one window to another. This will invalidate fromWindow in the storage and move the |
| * data to toWindow, and overwrite any existing data in toWindow |
| * |
| * @param fromWindow the window we want to migrate from |
| * @param toWindow the window we want to migrate to |
| */ |
| void migrateWindow(Window.SessionWindow<K> fromWindow, Window.SessionWindow<K> toWindow); |
| |
| /** |
| * Given the key, the timestamp and the gap, gets the data that falls into timestamp +/- gap. |
| * This is used for getting the entry the data given the timestamp belongs to, and for determining whether to merge |
| * session windows. |
| * This should only return at most two entries if sessions have been merged appropriately. |
| * |
| * @param key the key |
| * @param timestamp the timestamp |
| * @param gap the minimum gap |
| * @return the windows |
| */ |
| Collection<Map.Entry<Window.SessionWindow<K>, V>> getSessionEntries(K key, long timestamp, long gap); |
| } |