| /* |
| * 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.List; |
| import java.util.ArrayList; |
| |
| import org.apache.pig.EvalFunc; |
| import org.apache.pig.PigWarning; |
| import org.apache.pig.data.Tuple; |
| import org.apache.pig.data.DataType; |
| import org.apache.pig.impl.logicalLayer.schema.Schema; |
| import org.apache.pig.impl.logicalLayer.FrontendException; |
| import org.apache.pig.FuncSpec; |
| |
| /** |
| * LOWER implements eval function to convert a string to lower case |
| * Example: |
| * A = load 'mydata' as (name); |
| * B = foreach A generate LOWER(name); |
| */ |
| public class LOWER extends EvalFunc<String> { |
| |
| /** |
| * 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() == 0) |
| return null; |
| |
| try { |
| String str = (String)input.get(0); |
| return str.toLowerCase(); |
| } catch(Exception e){ |
| warn("Failed to process input; error - " + e.getMessage(), PigWarning.UDF_WARNING_1); |
| return null; |
| } |
| } |
| |
| /** |
| * This method gives a name to the column. |
| * @param input - schema of the input data |
| * @return schema of the input data |
| */ |
| @Override |
| public Schema outputSchema(Schema input) { |
| return new Schema(new Schema.FieldSchema(getSchemaName(this.getClass().getName().toLowerCase(), input), DataType.CHARARRAY)); |
| } |
| |
| /* (non-Javadoc) |
| * @see org.apache.pig.EvalFunc#getArgToFuncMapping() |
| */ |
| @Override |
| public List<FuncSpec> getArgToFuncMapping() throws FrontendException { |
| List<FuncSpec> funcList = new ArrayList<FuncSpec>(); |
| funcList.add(new FuncSpec(this.getClass().getName(), new Schema(new Schema.FieldSchema(null, DataType.CHARARRAY)))); |
| |
| return funcList; |
| } |
| |
| @Override |
| public boolean allowCompileTimeCalculation() { |
| return true; |
| } |
| |
| } |