| /* |
| * 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. |
| */ |
| |
| /** |
| * This is the main driver for parameter substitution |
| * http://wiki.apache.org/pig/ParameterSubstitution |
| */ |
| package org.apache.pig.tools.parameters; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| import java.io.IOException; |
| import java.io.BufferedReader; |
| import java.io.StringReader; |
| import java.io.Writer; |
| import java.util.Arrays; |
| |
| public class ParameterSubstitutionPreprocessor { |
| |
| private PreprocessorContext pc; |
| private final Log log = LogFactory.getLog(getClass()); |
| private PigFileParser pigParser; |
| |
| /** |
| * @param limit - max number of parameters to expect. Smaller values would |
| * would not cause incorrect behavior but would impact performance |
| */ |
| public ParameterSubstitutionPreprocessor(int limit) { |
| this(new PreprocessorContext(limit)); |
| } |
| |
| public ParameterSubstitutionPreprocessor(PreprocessorContext pc) { |
| this.pc = pc; |
| StringReader sr = null; |
| pigParser = new PigFileParser(sr); |
| pigParser.setContext(pc); |
| } |
| |
| /** |
| * This is the main API that takes script template and produces pig script |
| * @param pigInput - input stream that contains pig file |
| * @param pigOutput - stream where transformed file is written |
| * @param paramVal - map of parameter names to values |
| */ |
| public void genSubstitutedFile(BufferedReader pigInput, Writer pigOutput) throws ParseException { |
| // In case there is no EOL before EOF, add EOL for each line |
| String line = null; |
| StringBuilder blder = new StringBuilder(); |
| try { |
| while ((line = pigInput.readLine()) != null) { |
| blder.append(line).append("\n"); |
| } |
| } catch (IOException e) { |
| throw new ParseException(e.getMessage()); |
| } |
| |
| pigInput = new BufferedReader(new StringReader(blder.toString())); |
| |
| // perform the substitution |
| parsePigFile(pigInput , pigOutput); |
| } |
| |
| // Kept for compatibility with old interface |
| public void genSubstitutedFile(BufferedReader pigInput, Writer pigOutput, |
| String[] params, String[] paramFiles) throws ParseException { |
| try { |
| pc.loadParamVal(params == null ? null : Arrays.asList(params), |
| paramFiles == null ? null : Arrays.asList(paramFiles)); |
| genSubstitutedFile(pigInput, pigOutput); |
| } catch (IOException e) { |
| throw new ParseException(e.getMessage()); |
| } |
| } |
| |
| private void parsePigFile(BufferedReader in, Writer out) throws ParseException { |
| pigParser.setOutputWriter(out); |
| pigParser.ReInit(in); |
| try { |
| pigParser.Parse(); |
| //close input and output streams |
| in.close(); |
| out.flush(); |
| out.close(); |
| } catch (IOException e) { |
| RuntimeException rte = new RuntimeException(e.getMessage() , e); |
| throw rte; |
| } |
| } |
| } |