org.apache.hadoop.hive.ql.udf.UDFRegExpReplace Maven / Gradle / Ivy
/**
* 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.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.io.Text;
/**
* UDFRegExpReplace.
*
*/
@Description(name = "regexp_replace",
value = "_FUNC_(str, regexp, rep) - replace all substrings of str that "
+ "match regexp with rep", extended = "Example:\n"
+ " > SELECT _FUNC_('100-200', '(\\d+)', 'num') FROM src LIMIT 1;\n"
+ " 'num-num'")
public class UDFRegExpReplace extends UDF {
private final Text lastRegex = new Text();
private Pattern p = null;
private final Text lastReplacement = new Text();
private String replacementString = "";
private Text result = new Text();
public UDFRegExpReplace() {
}
public Text evaluate(Text s, Text regex, Text replacement) {
if (s == null || regex == null || replacement == null) {
return null;
}
// If the regex is changed, make sure we compile the regex again.
if (!regex.equals(lastRegex) || p == null) {
lastRegex.set(regex);
p = Pattern.compile(regex.toString());
}
Matcher m = p.matcher(s.toString());
// If the replacement is changed, make sure we redo toString again.
if (!replacement.equals(lastReplacement)) {
lastReplacement.set(replacement);
replacementString = replacement.toString();
}
StringBuffer sb = new StringBuffer();
while (m.find()) {
m.appendReplacement(sb, replacementString);
}
m.appendTail(sb);
result.set(sb.toString());
return result;
}
}