org.apache.hadoop.hive.ql.udf.UDFFromUnixTime Maven / Gradle / Ivy
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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 org.apache.hadoop.hive.ql.udf;
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.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
/**
* UDFFromUnixTime.
*
*/
@Description(name = "from_unixtime",
value = "_FUNC_(unix_time, format) - returns unix_time in the specified format",
extended = "Example:\n"
+ " > SELECT _FUNC_(0, 'yyyy-MM-dd HH:mm:ss') FROM src LIMIT 1;\n"
+ " '1970-01-01 00:00:00'")
public class UDFFromUnixTime extends UDF {
private SimpleDateFormat formatter;
private Text result = new Text();
private Text lastFormat = new Text();
public UDFFromUnixTime() {
}
private Text defaultFormat = new Text("yyyy-MM-dd HH:mm:ss");
public Text evaluate(IntWritable unixtime) {
return evaluate(unixtime, defaultFormat);
}
/**
* Convert UnixTime to a string format.
*
* @param unixtime
* The number of seconds from 1970-01-01 00:00:00
* @param format
* See
* http://java.sun.com/j2se/1.4.2/docs/api/java/text/SimpleDateFormat
* .html
* @return a String in the format specified.
*/
public Text evaluate(LongWritable unixtime, Text format) {
if (unixtime == null || format == null) {
return null;
}
return eval(unixtime.get(), format);
}
/**
* Convert UnixTime to a string format.
*
* @param unixtime
* The number of seconds from 1970-01-01 00:00:00
* @return a String in default format specified.
*/
public Text evaluate(LongWritable unixtime) {
if (unixtime == null) {
return null;
}
return eval(unixtime.get(), defaultFormat);
}
/**
* Convert UnixTime to a string format.
*
* @param unixtime
* The number of seconds from 1970-01-01 00:00:00
* @param format
* See
* http://java.sun.com/j2se/1.4.2/docs/api/java/text/SimpleDateFormat
* .html
* @return a String in the format specified.
*/
public Text evaluate(IntWritable unixtime, Text format) {
if (unixtime == null || format == null) {
return null;
}
return eval(unixtime.get(), format);
}
/**
* Internal evaluation function given the seconds from 1970-01-01 00:00:00 and
* the output text format.
*
* @param unixtime
* seconds of type long from 1970-01-01 00:00:00
* @param format
* display format. See
* http://java.sun.com/j2se/1.4.2/docs/api/java/text
* /SimpleDateFormat.html
* @return elapsed time in the given format.
*/
private Text eval(long unixtime, Text format) {
if (!format.equals(lastFormat)) {
formatter = new SimpleDateFormat(format.toString());
lastFormat.set(format);
}
// convert seconds to milliseconds
Date date = new Date(unixtime * 1000L);
result.set(formatter.format(date));
return result;
}
}