| /* |
| * 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.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; |
| |
| /** |
| * REPLACE implements eval function to replace part of a string. |
| * Example:<code> |
| * A = load 'mydata' as (name); |
| * B = foreach A generate REPLACE(name, 'blabla', 'bla'); |
| * The first argument is a string on which to perform the operation. The second argument |
| * is treated as a regular expression. The third argument is the replacement string. |
| * This is a wrapper around Java's String.replaceAll(String, String); |
| * |
| */ |
| public class REPLACE extends EvalFunc<String> |
| { |
| private Pattern mPattern = null; |
| |
| /** |
| * Method invoked on every tuple during foreach evaluation |
| * @param input tuple; first column is assumed to have the column to convert |
| * @exception java.io.IOException |
| */ |
| @Override |
| public String exec(Tuple input) throws IOException { |
| if (input == null || input.size() < 3) |
| return null; |
| |
| String source = (String)input.get(0); |
| String target = (String)input.get(1); |
| |
| if (source == null) { |
| return null; |
| } |
| |
| if (target == null) { |
| warn("Replace : Regular expression is null", PigWarning.UDF_WARNING_1); |
| return null; |
| } |
| |
| if (mPattern == null || ! target.equals(mPattern.pattern())) { |
| try { |
| mPattern = Pattern.compile(target); |
| } catch (Exception e) { |
| warn("Replace : Mal-Formed Regular expression : " + target, PigWarning.UDF_WARNING_1); |
| return null; |
| } |
| } |
| |
| String replacewith = (String)input.get(2); |
| |
| try { |
| return mPattern.matcher(source).replaceAll(replacewith); |
| }catch(Exception e){ |
| warn("Replace : Failed to process input; error - " + e.getMessage(), PigWarning.UDF_WARNING_1); |
| return null; |
| } |
| } |
| |
| @Override |
| public Schema outputSchema(Schema input) { |
| return new Schema(new Schema.FieldSchema(null, DataType.CHARARRAY)); |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.EvalFunc#getArgToFuncMapping() |
| */ |
| @Override |
| public List<FuncSpec> getArgToFuncMapping() throws FrontendException { |
| List<FuncSpec> funcList = new ArrayList<FuncSpec>(); |
| 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.CHARARRAY)); |
| funcList.add(new FuncSpec(this.getClass().getName(), s)); |
| return funcList; |
| } |
| |
| @Override |
| public boolean allowCompileTimeCalculation() { |
| return true; |
| } |
| } |