| /** |
| * 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.lib.util; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.conf.Configuration; |
| import org.w3c.dom.DOMException; |
| import org.w3c.dom.Document; |
| import org.w3c.dom.Element; |
| import org.w3c.dom.Node; |
| import org.w3c.dom.NodeList; |
| import org.w3c.dom.Text; |
| import org.xml.sax.SAXException; |
| |
| import javax.xml.parsers.DocumentBuilder; |
| import javax.xml.parsers.DocumentBuilderFactory; |
| import javax.xml.parsers.ParserConfigurationException; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.util.Map; |
| |
| /** |
| * Configuration utilities. |
| */ |
| @InterfaceAudience.Private |
| public abstract class ConfigurationUtils { |
| |
| /** |
| * Copy configuration key/value pairs from one configuration to another if a property exists in the target, it gets |
| * replaced. |
| * |
| * @param source source configuration. |
| * @param target target configuration. |
| */ |
| public static void copy(Configuration source, Configuration target) { |
| Check.notNull(source, "source"); |
| Check.notNull(target, "target"); |
| for (Map.Entry<String, String> entry : source) { |
| target.set(entry.getKey(), entry.getValue()); |
| } |
| } |
| |
| /** |
| * Injects configuration key/value pairs from one configuration to another if the key does not exist in the target |
| * configuration. |
| * |
| * @param source source configuration. |
| * @param target target configuration. |
| */ |
| public static void injectDefaults(Configuration source, Configuration target) { |
| Check.notNull(source, "source"); |
| Check.notNull(target, "target"); |
| for (Map.Entry<String, String> entry : source) { |
| if (target.get(entry.getKey()) == null) { |
| target.set(entry.getKey(), entry.getValue()); |
| } |
| } |
| } |
| |
| /** |
| * Returns a new ConfigurationUtils instance with all inline values resolved. |
| * |
| * @return a new ConfigurationUtils instance with all inline values resolved. |
| */ |
| public static Configuration resolve(Configuration conf) { |
| Configuration resolved = new Configuration(false); |
| for (Map.Entry<String, String> entry : conf) { |
| resolved.set(entry.getKey(), conf.get(entry.getKey())); |
| } |
| return resolved; |
| } |
| |
| // Canibalized from FileSystemAccess <code>Configuration.loadResource()</code>. |
| |
| /** |
| * Create a configuration from an InputStream. |
| * <p> |
| * ERROR canibalized from <code>Configuration.loadResource()</code>. |
| * |
| * @param is inputstream to read the configuration from. |
| * |
| * @throws IOException thrown if the configuration could not be read. |
| */ |
| public static void load(Configuration conf, InputStream is) throws IOException { |
| try { |
| DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance(); |
| // ignore all comments inside the xml file |
| docBuilderFactory.setIgnoringComments(true); |
| DocumentBuilder builder = docBuilderFactory.newDocumentBuilder(); |
| Document doc = builder.parse(is); |
| parseDocument(conf, doc); |
| } catch (SAXException e) { |
| throw new IOException(e); |
| } catch (ParserConfigurationException e) { |
| throw new IOException(e); |
| } |
| } |
| |
| // Canibalized from FileSystemAccess <code>Configuration.loadResource()</code>. |
| private static void parseDocument(Configuration conf, Document doc) throws IOException { |
| try { |
| Element root = doc.getDocumentElement(); |
| if (!"configuration".equals(root.getTagName())) { |
| throw new IOException("bad conf file: top-level element not <configuration>"); |
| } |
| 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())) { |
| throw new IOException("bad conf file: element not <property>"); |
| } |
| NodeList fields = prop.getChildNodes(); |
| String attr = null; |
| String value = null; |
| 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 (attr != null && value != null) { |
| conf.set(attr, value); |
| } |
| } |
| |
| } catch (DOMException e) { |
| throw new IOException(e); |
| } |
| } |
| |
| } |