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

Introduction

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

Source

/**
 * 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.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

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;

@description(name = "regexp_extract", value = "_FUNC_(str, regexp[, idx]) - extracts a group that matches regexp", extended = "Example:\n"
        + "  > SELECT _FUNC_('100-200', '(\\d+)-(\\d+)', 1) FROM src LIMIT 1;\n" + "  '100'")
public class UDFRegExpExtract extends UDF {
    private static Log LOG = LogFactory.getLog(UDFRegExpExtract.class.getName());

    private String lastRegex = null;
    private Pattern p = null;

    public UDFRegExpExtract() {
    }

    public String evaluate(String s, String regex, Integer extractIndex) {
        if (s == null || regex == null) {
            return null;
        }
        if (!regex.equals(lastRegex) || p == null) {
            lastRegex = regex;
            p = Pattern.compile(regex);
        }
        Matcher m = p.matcher(s);
        if (m.find()) {
            MatchResult mr = m.toMatchResult();
            return mr.group(extractIndex);
        }
        return "";
    }

    public String evaluate(String s, String regex) {
        return this.evaluate(s, regex, 1);
    }

}