Java tutorial
/** * 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.hadoop.hive.ql.udf; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.hive.ql.exec.Description; import org.apache.hadoop.hive.ql.exec.UDF; import org.apache.hadoop.hive.serde2.io.DoubleWritable; @Description(name = "E", value = "_FUNC_() - returns E ", extended = "Example:\n" + " > SELECT _FUNC_() FROM src LIMIT 1;\n" + " 2.718281828459045") public class UDFE extends UDF { @SuppressWarnings("unused") private static Log LOG = LogFactory.getLog(UDFE.class.getName()); DoubleWritable result = new DoubleWritable(); public UDFE() { super(); result.set(Math.E); } public DoubleWritable evaluate() { return result; } }