com.twitter.heron.streamlet.KeyValue Maven / Gradle / Ivy
// Copyright 2016 Twitter. All rights reserved.
//
// Licensed 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.twitter.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 implements Serializable {
private static final long serialVersionUID = -7120757965590727554L;
private K key;
private V value;
public static KeyValue create(R k, T v) {
return new KeyValue(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) + " }";
}
}