/*
* 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.aliyun.odps.udf;
/**
* UDF 基类
* UDF (User Defined Scalar Function) 自定义函数，其输入输出是一对一的关系，即读入一行数据，写出一条输出值。
* <p>
* 自定义 UDF 需要继承这个类来实现一个 UDF，并根据输入输出类型编写 evaluate 方法。
* </p>
* 例如:
* <pre>
* public class MyPlus extends UDF {
* Long evaluate(Long a, Long b) {
* if (a == null || b == null) {
* return null;
* }
* return a + b;
* }
* }
* </pre>
*/
public class UDF implements ContextFunction {
@Override
public void setup(ExecutionContext ctx) throws UDFException {
}
@Override
public void close() throws UDFException {
}
}