| /** |
| * 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.tools.rumen; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.util.Properties; |
| |
| import javax.xml.parsers.DocumentBuilder; |
| import javax.xml.parsers.DocumentBuilderFactory; |
| import javax.xml.parsers.ParserConfigurationException; |
| |
| import org.w3c.dom.Document; |
| import org.w3c.dom.Element; |
| import org.w3c.dom.NodeList; |
| import org.w3c.dom.Node; |
| import org.w3c.dom.Text; |
| import org.xml.sax.SAXException; |
| |
| /** |
| * {@link JobConfigurationParser} parses the job configuration xml file, and |
| * extracts configuration properties. It parses the file using a |
| * stream-parser and thus is more memory efficient. [This optimization may be |
| * postponed for a future release] |
| */ |
| public class JobConfigurationParser { |
| |
| /** |
| * Parse the job configuration file (as an input stream) and return a |
| * {@link Properties} collection. The input stream will not be closed after |
| * return from the call. |
| * |
| * @param input |
| * The input data. |
| * @return A {@link Properties} collection extracted from the job |
| * configuration xml. |
| * @throws IOException |
| */ |
| static Properties parse(InputStream input) throws IOException { |
| Properties result = new Properties(); |
| |
| try { |
| DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); |
| |
| DocumentBuilder db = dbf.newDocumentBuilder(); |
| |
| Document doc = db.parse(input); |
| |
| Element root = doc.getDocumentElement(); |
| |
| if (!"configuration".equals(root.getTagName())) { |
| System.out.print("root is not a configuration node"); |
| return null; |
| } |
| |
| NodeList props = root.getChildNodes(); |
| |
| for (int i = 0; i < props.getLength(); ++i) { |
| Node propNode = props.item(i); |
| if (!(propNode instanceof Element)) |
| continue; |
| Element prop = (Element) propNode; |
| if (!"property".equals(prop.getTagName())) { |
| System.out.print("bad conf file: element not <property>"); |
| } |
| NodeList fields = prop.getChildNodes(); |
| String attr = null; |
| String value = null; |
| @SuppressWarnings("unused") |
| boolean finalParameter = false; |
| for (int j = 0; j < fields.getLength(); j++) { |
| Node fieldNode = fields.item(j); |
| if (!(fieldNode instanceof Element)) { |
| continue; |
| } |
| |
| Element field = (Element) fieldNode; |
| if ("name".equals(field.getTagName()) && field.hasChildNodes()) { |
| attr = ((Text) field.getFirstChild()).getData().trim(); |
| } |
| if ("value".equals(field.getTagName()) && field.hasChildNodes()) { |
| value = ((Text) field.getFirstChild()).getData(); |
| } |
| if ("final".equals(field.getTagName()) && field.hasChildNodes()) { |
| finalParameter = |
| "true".equals(((Text) field.getFirstChild()).getData()); |
| } |
| } |
| |
| if (attr != null && value != null) { |
| result.put(attr, value); |
| } |
| } |
| } catch (ParserConfigurationException e) { |
| return null; |
| } catch (SAXException e) { |
| return null; |
| } |
| |
| return result; |
| } |
| } |