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package net.myvietnam.mvncore.configuration;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2002-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowledgement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgement may appear in the software itself,
 *    if and wherever such third-party acknowledgements normally appear.
 *
 * 4. The names "The Jakarta Project", "Commons", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import java.io.IOException;
import java.io.Writer;
import java.util.NoSuchElementException;

import org.apache.commons.digester.Digester;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.DOMWriter;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.xml.sax.SAXException;

/**
 * <p>A helper class that supports XML-like processing for configuration
 * objects.</p>
 * <p>This class provides a set of methods that all have something to do with
 * treating a <code>Configuration object as a XML document. So a
 * configuration can be transformed into a <code>Document (either
 * dom4j or w3c), saved as an XML file or passed to Digester.</p>
 * <p>Implementation note: This class is not thread safe.

* * @author <a href="mailto:oliver.heger@t-online.de">Oliver Heger * @version $Id: ConfigurationXMLDocument.java,v 1.1 2003/12/09 08:25:30 huumai Exp $ */ public class ConfigurationXMLDocument { /** Constant for the class element.*/ protected static final String ELEM_CLASS = "config/class"; /** Constant for the property element.*/ protected static final String ELEM_PROPERTY = "config/class/property"; /** Constant for the name attribute.*/ protected static final String ATTR_NAME = "name"; /** Constant for the value attribute.*/ protected static final String ATTR_VALUE = "value"; /** Stores the configuration object this object operates on.*/ private Configuration configuration; /** * Creates a new instance of <code>ConfigurationXMLDocument * and sets the configuration object to be processed. * @param config the configuration object */ public ConfigurationXMLDocument(Configuration config) { setConfiguration(config); } /** * Returns the <code>Configuration object for this document. * @return the <code>Configuration object */ public Configuration getConfiguration() { return configuration; } /** * Sets the <code>Configuration object this document operates on. * @param configuration the <code>Configuration object */ public void setConfiguration(Configuration configuration) { this.configuration = configuration; } /** * Returns a <code>XMLReader object for the specified configuration * object. This reader can then be used to perform XML-like processing on * the configuration. * @param config the configuration object * @return a XMLReader for this configuration */ public static ConfigurationXMLReader createXMLReader(Configuration config) { if (config instanceof HierarchicalConfiguration) { return new HierarchicalConfigurationXMLReader( (HierarchicalConfiguration) config); } /* if */ else { return new BaseConfigurationXMLReader(config); } /* else */ } /** * Returns a <code>XMLReader object for the actual configuration * object. * @return a XMLReader for the actual configuration */ public ConfigurationXMLReader createXMLReader() { return createXMLReader((String) null); } /** * Returns a <code>ConfigurationXMLReader object for the subset * configuration specified by the given prefix. If no properties are found * under this prefix, a <code>NoSuchElementException * exception will be thrown. * @param prefix the prefix of the configuration keys that belong to the * subset; can be <b>null, then the whole configuration is affected * @return a XMLReader for the specified subset configuration */ public ConfigurationXMLReader createXMLReader(String prefix) { return createXMLReader(configForKey(prefix)); } /** * Transforms the wrapped configuration into a dom4j document. * @param prefix a prefix for the keys to process; can be <b>null, * then all keys in the configuration will be added to the document * @param rootName the name of the root element in the document; can be * <b>null, then a default name will be used * @return the document * @throws DocumentException if an error occurs */ public Document getDocument(String prefix, String rootName) throws DocumentException { ConfigurationXMLReader xmlReader = createXMLReader(prefix); if (rootName != null) { xmlReader.setRootName(rootName); } /* if */ SAXReader reader = new SAXReader(xmlReader); return reader.read(getClass().getName()); } /** * Transforms the wrapped configuration into a dom4j document. The root * element will be given a default name. * @param prefix a prefix for the keys to process; can be <b>null, * then all keys in the configuration will be added to the document * @return the document * @throws DocumentException if an error occurs */ public Document getDocument(String prefix) throws DocumentException { return getDocument(prefix, null); } /** * Transforms the wrapped configuration into a dom4j document. The root * element will be given a default name. * @return the document * @throws DocumentException if an error occurs */ public Document getDocument() throws DocumentException { return getDocument(null, null); } /** * Transforms the wrapped configuration into a w3c document. * @param prefix a prefix for the keys to process; can be <b>null, * then all keys in the configuration will be added to the document * @param rootName the name of the root element in the document; can be * <b>null, then a default name will be used * @return the document * @throws DocumentException if an error occurs */ public org.w3c.dom.Document getW3cDocument(String prefix, String rootName) throws DocumentException { return toW3cDocument(getDocument(prefix, rootName)); } /** * Transforms the wrapped configuration into a w3c document. The root * element will be given a default name. * @param prefix a prefix for the keys to process; can be <b>null, * then all keys in the configuration will be added to the document * @return the document * @throws DocumentException if an error occurs */ public org.w3c.dom.Document getW3cDocument(String prefix) throws DocumentException { return getW3cDocument(prefix, null); } /** * Transforms the wrapped configuration into a w3c document. The root * element will be given a default name. * @return the document * @throws DocumentException if an error occurs */ public org.w3c.dom.Document getW3cDocument() throws DocumentException { return getW3cDocument(null, null); } /** * Converts a dom4j document into a w3c document. * @param doc the dom4j document * @return the w3c document * @throws DocumentException if an error occurs */ static org.w3c.dom.Document toW3cDocument(Document doc) throws DocumentException { return new DOMWriter().write(doc); } /** * Helper method for constructing a subset if necessary. Depending on * the passed in key this method either returns the wrapped configuration * or the specified subset of it. * @param key the key * @return the configuration for that key */ private Configuration configForKey(String key) { Configuration conf = (key == null) ? getConfiguration() : getConfiguration().subset(key); // undefined? if(conf == null || (conf instanceof CompositeConfiguration && ((CompositeConfiguration) conf).getNumberOfConfigurations() < 2)) { throw new NoSuchElementException("No subset with key " + key); } /* if */ return conf; } /** * <p>Creates and initializes an object specified in the configuration * using Digester.</p> * <p>This method first constructs a subset configuration with the keys * starting with the given prefix. It then transforms this subset into a * XML document and let that be processed by Digester. The result of this * processing is returned.</p> * <p>The method is intended to be used for creating simple objects that * are specified somewhere in the configuration in a standard way. The * following fragment shows how a configuration file must look like to be * understood by the default Digester rule set used by this method:</p> * <p>
     * ...
     *   <class name="mypackage.MyClass"/>
     *   <args>
     *     <property name="myFirstProperty" value="myFirstValue"/>
     *     <property name="MySecondProperty" value="mySecondValue"/>
     *     ...
     *   </args>
     * ...
     * </pre>

* @param prefix the prefix of the keys that are passed to Digester; can * be <b>null, then the whole configuration will be processed * @return the result of the Digester processing * @throws IOException if an IOException occurs * @throws SAXException if a SAXException occurs */ public Object callDigester(String prefix) throws IOException, SAXException { Digester digester = getDefaultDigester(prefix); return digester.parse(getClass().getName()); } /** * Returns a default Digester instance. This instance is used for the * simple object creation feature. * @param prefix the prefix of the keys to be processed; can be * <b>null, then the whole configuration is meant * @return the default Digester instance */ protected Digester getDefaultDigester(String prefix) { Digester digester = createDefaultDigester(prefix); setupDefaultDigester(digester); return digester; } /** * Creates the default Digester instance for the given prefix. This method * is called by <code>getDefaultDigester(). * @param prefix the prefix of the keys to be processed; can be * <b>null, then the whole configuration is meant * @return the default Digester instance */ protected Digester createDefaultDigester(String prefix) { return new Digester(createXMLReader(prefix)); } /** * Initializes the default digester instance used for simple object * creation. Here all needed properties and rules can be set. This base * implementation sets default rules for object creation as explained in * the comment for the <code>callDigester() methods. * @param digester the digester instance to be initialized */ protected void setupDefaultDigester(Digester digester) { digester.addObjectCreate(ELEM_CLASS, ATTR_NAME, Object.class); digester.addSetProperty(ELEM_PROPERTY, ATTR_NAME, ATTR_VALUE); } /** * Writes a configuration (or parts of it) to the given writer. * @param out the output writer * @param prefix the prefix of the subset to write; if <b>null, the * whole configuration is written * @param root the name of the root element of the resulting document; * <b>null for a default name * @param pretty flag for the pretty print mode * @throws IOException if an IO error occurs * @throws DocumentException if there is an error during processing */ public void write(Writer out, String prefix, String root, boolean pretty) throws IOException, DocumentException { OutputFormat format = (pretty) ? OutputFormat.createPrettyPrint() : OutputFormat.createCompactFormat(); XMLWriter writer = new XMLWriter(out, format); writer.write(getDocument(prefix, root)); } /** * Writes a configuration (or parts of it) to the given writer. * This overloaded version always uses pretty print mode. * @param out the output writer * @param prefix the prefix of the subset to write; if <b>null, the * whole configuration is written * @param root the name of the root element of the resulting document; * <b>null for a default name * @throws IOException if an IO error occurs * @throws DocumentException if there is an error during processing */ public void write(Writer out, String prefix, String root) throws IOException, DocumentException { write(out, prefix, root, true); } /** * Writes a configuration (or parts of it) to the given writer. * The resulting document's root element will be given a default name. * @param out the output writer * @param prefix the prefix of the subset to write; if <b>null, the * whole configuration is written * @param pretty flag for the pretty print mode * @throws IOException if an IO error occurs * @throws DocumentException if there is an error during processing */ public void write(Writer out, String prefix, boolean pretty) throws IOException, DocumentException { write(out, prefix, null, pretty); } /** * Writes a configuration (or parts of it) to the given writer. * The resulting document's root element will be given a default name. * This overloaded version always uses pretty print mode. * @param out the output writer * @param prefix the prefix of the subset to write; if <b>null, the * whole configuration is written * @throws IOException if an IO error occurs * @throws DocumentException if there is an error during processing */ public void write(Writer out, String prefix) throws IOException, DocumentException { write(out, prefix, true); } /** * Writes the wrapped configuration to the given writer. * The resulting document's root element will be given a default name. * @param out the output writer * @param pretty flag for the pretty print mode * @throws IOException if an IO error occurs * @throws DocumentException if there is an error during processing */ public void write(Writer out, boolean pretty) throws IOException, DocumentException { write(out, null, null, pretty); } /** * Writes the wrapped configuration to the given writer. * The resulting document's root element will be given a default name. * This overloaded version always uses pretty print mode. * @param out the output writer * @throws IOException if an IO error occurs * @throws DocumentException if there is an error during processing */ public void write(Writer out) throws IOException, DocumentException { write(out, true); } }
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