| /** |
| * 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.heron.streamlet; |
| |
| import java.io.Serializable; |
| |
| /** |
| * Certain operations in the Streamlet API, like join/reduce, necessitate |
| * the concept of key value pairs. This file defines a generic KeyValue |
| * class. We make the KeyValue class serializable to allow it to be |
| * serialized between components. |
| */ |
| public final class KeyValue<K, V> implements Serializable { |
| private static final long serialVersionUID = -7120757965590727554L; |
| private K key; |
| private V value; |
| |
| public static <R, T> KeyValue<R, T> create(R k, T v) { |
| return new KeyValue<R, T>(k, v); |
| } |
| |
| KeyValue() { |
| // nothing really |
| } |
| |
| public KeyValue(K k, V v) { |
| this.key = k; |
| this.value = v; |
| } |
| public K getKey() { |
| return key; |
| } |
| public void setKey(K k) { |
| this.key = k; |
| } |
| public V getValue() { |
| return value; |
| } |
| public void setValue(V v) { |
| this.value = v; |
| } |
| |
| @Override |
| public String toString() { |
| return "{ " + String.valueOf(key) + " : " + String.valueOf(value) + " }"; |
| } |
| } |