Java tutorial
package brickhouse.udf.date; /** * Copyright 2012 Klout, Inc * * 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. * **/ import org.apache.hadoop.hive.ql.exec.UDF; import org.apache.log4j.Logger; import org.joda.time.*; import org.joda.time.format.DateTimeFormatter; /** * Simple date add UDF. * Would use the Hive standard function, but that assumes a * date format of "YYYY-MM-DD", and we would prefer "YYYYMMDD" * and it is too awkward to include lots of substring functions in our hive * * */ public class AddDaysUDF extends UDF { private static final Logger LOG = Logger.getLogger(AddDaysUDF.class); private static final DateTimeFormatter YYYYMMDD = org.joda.time.format.DateTimeFormat.forPattern("YYYYMMdd"); public String evaluate(String dateStr, int numDays) { DateTime dt = YYYYMMDD.parseDateTime(dateStr); DateTime addedDt = dt.plusDays(numDays); String addedDtStr = YYYYMMDD.print(addedDt); return addedDtStr; } }