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org.apache.pig.builtin.REGEX_EXTRACT 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.pig.builtin;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.pig.EvalFunc;
import org.apache.pig.FuncSpec;
import org.apache.pig.PigWarning;
import org.apache.pig.data.DataType;
import org.apache.pig.data.Tuple;
import org.apache.pig.impl.logicalLayer.FrontendException;
import org.apache.pig.impl.logicalLayer.schema.Schema;

/**
* 
*
Syntax:
*
String RegexExtract(String expression, String regex, int match_index).
*
Input:
*
expression-source string.
*
regex-regular expression.
*
match_index-index of the group to extract.
*
Output:
*
extracted group, if fail, return null.
*
*/ public class REGEX_EXTRACT extends EvalFunc { String mExpression = null; Pattern mPattern = null; @Override public Schema outputSchema(Schema input) { try { return new Schema(new Schema.FieldSchema(getSchemaName(this.getClass().getName().toLowerCase(), input), DataType.CHARARRAY)); } catch (Exception e) { return null; } } public String exec(Tuple input) throws IOException { if (input.size()!=3) { String msg = "RegexExtract : Only 3 parameters are allowed."; throw new IOException(msg); } if (input.get(0)==null) return null; try { if (!input.get(1).equals(mExpression)) { try { mExpression = (String)input.get(1); mPattern = Pattern.compile(mExpression); } catch (Exception e) { String msg = "RegexExtract : Mal-Formed Regular expression : "+input.get(1); throw new IOException(msg); } } } catch (NullPointerException e) { String msg = "RegexExtract : Regular expression is null"; throw new IOException(msg); } int mIndex = (Integer)input.get(2); Matcher m = mPattern.matcher((String)input.get(0)); if (m.find()&&m.groupCount()>=mIndex) { return m.group(mIndex); } warn("RegexExtract : Cannot extract group for input "+input.get(0), PigWarning.UDF_WARNING_1); return null; } @Override public List getArgToFuncMapping() throws FrontendException { List funcList = new ArrayList(); Schema s = new Schema(); s.add(new Schema.FieldSchema(null, DataType.CHARARRAY)); s.add(new Schema.FieldSchema(null, DataType.CHARARRAY)); s.add(new Schema.FieldSchema(null, DataType.INTEGER)); funcList.add(new FuncSpec(this.getClass().getName(), s)); return funcList; } }




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