org.apache.hadoop.hive.ql.udf.UDFADD_MONTHS.java Source code

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Here is the source code for org.apache.hadoop.hive.ql.udf.UDFADD_MONTHS.java

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/**
* Tencent is pleased to support the open source community by making TDW available.
* Copyright (C) 2014 THL A29 Limited, a Tencent company. 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 org.apache.hadoop.hive.ql.udf;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.TimeZone;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.hive.ql.exec.description;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;

@description(name = "add_months", value = "_FUNC_(date1, n) - returns a date plus n months", extended = "Example:\n "
        + "  > SELECT _FUNC_('2001-08-03', 3) FROM src LIMIT 1;\n" + "  '2001-11-03'"
        + "  > SELECT _FUNC_('20010803', 3) FROM src LIMIT 1;\n" + "  '20011103'")
public class UDFADD_MONTHS extends UDF {

    private static Log LOG = LogFactory.getLog(UDFADD_MONTHS.class.getName());

    private SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");

    private SimpleDateFormat formatterNoLine = new SimpleDateFormat("yyyyMMdd");

    private Calendar calendar = Calendar.getInstance();

    Text result = new Text();

    public UDFADD_MONTHS() {
    }

    public Text evaluate(Text dateString1, IntWritable months) {

        if (dateString1 == null || months == null) {
            return null;
        }

        try {

            Date inDate;
            boolean hasLine = false;
            for (int i = 0; i < dateString1.toString().length(); i++) {
                if (dateString1.toString().charAt(i) == '-') {
                    hasLine = true;
                    break;
                }
            }

            if (!hasLine) {
                if (dateString1.toString().trim().length() > 8) {
                    return null;
                }
                inDate = formatterNoLine.parse(dateString1.toString().trim());
            } else {
                inDate = formatter.parse(dateString1.toString());
            }

            calendar.setTime(inDate);
            int fff = calendar.get(Calendar.ERA);
            if (fff == GregorianCalendar.BC)
                return null;
            int yyy = calendar.get(Calendar.YEAR);
            if ((yyy < 1900) || (yyy > 9999))
                return null;
            int mmm = calendar.get(Calendar.MONTH);
            int rrr = yyy + (months.get() + mmm) / 12;
            if ((rrr < 1900) || (rrr > 9999))
                return null;
            calendar.add(Calendar.DAY_OF_MONTH, 1);
            if (calendar.get(Calendar.DAY_OF_MONTH) == 1) {
                calendar.add(Calendar.MONTH, months.get());
                calendar.add(Calendar.DAY_OF_MONTH, -1);
            } else {
                calendar.add(Calendar.DAY_OF_MONTH, -1);
                calendar.add(Calendar.MONTH, months.get());
            }
            yyy = calendar.get(Calendar.YEAR);
            if ((yyy < 1900) || (yyy > 9999))
                return null;
            Date newDate = calendar.getTime();

            if (!hasLine) {
                result.set(formatterNoLine.format(newDate));
            } else {
                result.set(formatter.format(newDate));
            }
            return result;
        } catch (ParseException e) {
            return null;
        }
    }

}