com.kit.udf.UDFDateFormat.java Source code

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Here is the source code for com.kit.udf.UDFDateFormat.java

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/**
 * 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.kit.udf;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.hive.ql.udf.UDFType;
import org.apache.hadoop.io.Text;

/**
 * UDFDateFormat
 */

@Description(name = "date_format", value = "_FUNC_(dateText,pattern) - Return time string with given pattern. ", extended = "Convert time string with 'yyyy-MM-dd HH:mm:ss' pattern to time string with given pattern.\n"
        + " (see [http://java.sun.com/j2se/1.4.2/docs/api/java/text/SimpleDateFormat.html])\n\n" + "Example:\n"
        + " > SELECT _FUNC_ ('2011-05-11 12:05:11','yyyyMMdd') FRom src LIMIT 1;\n" + "20110511")

@UDFType(deterministic = false)
public class UDFDateFormat extends UDF {
    private final SimpleDateFormat standardFormatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    private final SimpleDateFormat formatter = new SimpleDateFormat();

    public UDFDateFormat() {
        standardFormatter.setLenient(false);
        formatter.setLenient(false);
    }

    Text result = new Text();
    Text lastPatternText = new Text();

    public Text evaluate(Text dateText, Text patternText) {
        if (dateText == null || patternText == null) {
            return null;
        }

        try {
            if (!patternText.equals(lastPatternText)) {
                formatter.applyPattern(patternText.toString());
                lastPatternText.set(patternText);
            }
        } catch (Exception e) {
            return null;
        }

        Date date;
        try {
            date = standardFormatter.parse(dateText.toString());
            result.set(formatter.format(date));
            return result;
        } catch (ParseException e) {
            return null;
        }
    }
}