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.Description; import org.apache.hadoop.hive.ql.exec.UDF; import org.apache.log4j.Logger; import org.joda.time.*; import org.joda.time.format.DateTimeFormatter; /** * Figures out the day number in the calander year of a given date string in YYYYMMDD format * 'YYYYMMddHH' * * */ @Description(name = "dayofyear", value = "_FUNC_(YYYYMMDD) - Generates number of calander days (1-365) for a given date string ") public class DayOfYearUDF extends UDF { private static final DateTimeFormatter YYYYMMDD = org.joda.time.format.DateTimeFormat.forPattern("YYYYMMdd"); public static int evaluate(String dateStr) { DateTime dt = YYYYMMDD.parseDateTime(dateStr); return dt.getDayOfYear(); } }