Java tutorial
/*-- Copyright (C) 2001 Brett McLaughlin. 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 disclaimer that follows these conditions in the documentation and/or other materials provided with the distribution. 3. The name "Java and XML" must not be used to endorse or promote products derived from this software without prior written permission. For written permission, please contact brett@newInstance.com. In addition, we request (but do not require) that you include in the end-user documentation provided with the redistribution and/or in the software itself an acknowledgement equivalent to the following: "This product includes software developed for the 'Java and XML' book, by Brett McLaughlin (O'Reilly & Associates)." 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 JDOM AUTHORS OR THE PROJECT 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. */ import java.io.File; import java.io.FileReader; import java.io.FileWriter; import java.io.InputStream; import java.io.InputStreamReader; import java.io.IOException; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.Reader; import java.io.Writer; import java.util.Enumeration; import java.util.Iterator; import java.util.List; import java.util.Properties; import org.jdom.Attribute; import org.jdom.Comment; import org.jdom.Document; import org.jdom.Element; import org.jdom.JDOMException; import org.jdom.input.SAXBuilder; import org.jdom.output.XMLOutputter; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.util.Enumeration; import java.util.Properties; import org.jdom.output.XMLOutputter; /** * <b><code>PropsToXML</code></b> takes a standard Java properties * file, and converts it into an XML format. This makes properties * like <code>enhydra.classpath.separator</code> "groupbable" by * "enhydra", "classpath", and by the key name, "separator", which * the standard Java <code>java.util.Properties</code> class does * not allow. */ public class PropsToXML { /** * <p> This will take the supplied properties file, and * convert that file to an XML representation, which is * then output to the supplied XML document filename. </p> * * @param propertiesFilename file to read in as Java properties. * @param xmlFilename file to output XML representation to. * @throws <code>IOException</code> - when errors occur. */ public void convert(String propertiesFilename, String xmlFilename) throws IOException { // Get Java Properties object FileInputStream input = new FileInputStream(propertiesFilename); Properties props = new Properties(); props.load(input); // Convert to XML convertToXML(props, xmlFilename); } /** * <p> This will handle the detail of conversion from a Java * <code>Properties</code> object to an XML document. </p> * * @param props <code>Properties</code> object to use as input. * @param xmlFilename file to output XML to. * @throws <code>IOException</code> - when errors occur. */ private void convertToXML(Properties props, String xmlFilename) throws IOException { // Create a new JDOM Document with a root element "properties" Element root = new Element("properties"); Document doc = new Document(root); // Get the property names Enumeration propertyNames = props.propertyNames(); while (propertyNames.hasMoreElements()) { String propertyName = (String) propertyNames.nextElement(); String propertyValue = props.getProperty(propertyName); createXMLRepresentation(root, propertyName, propertyValue); } // Output document to supplied filename XMLOutputter outputter = new XMLOutputter(" ", true); FileOutputStream output = new FileOutputStream(xmlFilename); outputter.output(doc, output); } /** * <p> This will convert a single property and its value to * an XML element and textual value. </p> * * @param root JDOM root <code>Element</code> to add children to. * @param propertyName name to base element creation on. * @param propertyValue value to use for property. */ private void createXMLRepresentation(Element root, String propertyName, String propertyValue) { /* Element element = new Element(propertyName); element.setText(propertyValue); root.addContent(element); */ int split; String name = propertyName; Element current = root; Element test = null; while ((split = name.indexOf(".")) != -1) { String subName = name.substring(0, split); name = name.substring(split + 1); // Check for existing element if ((test = current.getChild(subName)) == null) { Element subElement = new Element(subName); current.addContent(subElement); current = subElement; } else { current = test; } } // When out of loop, what's left is the final element's name Element last = new Element(name); // last.setText(propertyValue); last.setAttribute("value", propertyValue); current.addContent(last); } /** * <p> Provide a static entry point for running. </p> */ public static void main(String[] args) { if (args.length != 2) { System.out.println("Usage: java PropsToXML " + "[properties file] [XML file for output]"); System.exit(0); } try { PropsToXML propsToXML = new PropsToXML(); propsToXML.convert(args[0], args[1]); } catch (Exception e) { e.printStackTrace(); } } } /*-- Copyright (C) 2001 Brett McLaughlin. 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 disclaimer that follows these conditions in the documentation and/or other materials provided with the distribution. 3. The name "Java and XML" must not be used to endorse or promote products derived from this software without prior written permission. For written permission, please contact brett@newInstance.com. In addition, we request (but do not require) that you include in the end-user documentation provided with the redistribution and/or in the software itself an acknowledgement equivalent to the following: "This product includes software developed for the 'Java and XML' book, by Brett McLaughlin (O'Reilly & Associates)." 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 JDOM AUTHORS OR THE PROJECT 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. */ /** * <b><code>XMLProperties</code></b> extends Java's * <code>java.util.Properties</code> class, and provides * behavior similar to properties but that use XML as the * input and output format. */ class XMLProperties extends Properties { /** * <p> This overrides the default <code>load()</code> * behavior to read from an XML document. </p> * * @param reader the reader to read XML from * @throws <code>IOException</code> - when errors occur reading. */ public void load(Reader reader) throws IOException { try { // Load XML into JDOM Document SAXBuilder builder = new SAXBuilder(); Document doc = builder.build(reader); // Turn into properties objects loadFromElements(doc.getRootElement().getChildren(), new StringBuffer("")); } catch (JDOMException e) { throw new IOException(e.getMessage()); } } /** * <p> This overrides the default <code>load()</code> * behavior to read from an XML document. </p> * * @param inputStream the input stream * @throws <code>IOException</code> - when errors occur reading. */ public void load(InputStream inputStream) throws IOException { load(new InputStreamReader(inputStream)); } /** * <p> This overrides the default <code>load()</code> * behavior to read from an XML document. </p> * * @param xmlDocument the XML document to read * @throws <code>IOException</code> - when errors occur reading. */ public void load(File xmlDocument) throws IOException { load(new FileReader(xmlDocument)); } /** * <p>This helper method loads the XML properties from a specific * XML element, or set of elements.</p> * * @param elements <code>List</code> of elements to load from. * @param baseName the base name of this property. */ private void loadFromElements(List elements, StringBuffer baseName) { // Iterate through each element for (Iterator i = elements.iterator(); i.hasNext();) { Element current = (Element) i.next(); String name = current.getName(); String text = current.getTextTrim(); // String text = current.getAttributeValue("value"); // Don't add "." if no baseName if (baseName.length() > 0) { baseName.append("."); } baseName.append(name); // See if we have an element value if ((text == null) || (text.equals(""))) { // If no text, recurse on children loadFromElements(current.getChildren(), baseName); } else { // If text, this is a property setProperty(baseName.toString(), text); } // On unwind from recursion, remove last name if (baseName.length() == name.length()) { baseName.setLength(0); } else { baseName.setLength(baseName.length() - (name.length() + 1)); } } } /** * @deprecated This method does not throw an IOException * if an I/O error occurs while saving the property list. * As of the Java 2 platform v1.2, the preferred way to save * a properties list is via the * <code>{@link store(OutputStream out, String header}</code> * method. */ public void save(OutputStream out, String header) { try { store(out, header); } catch (IOException ignored) { // Deprecated version doesn't pass errors } } /** * <p> This will output the properties in this object * as XML to the supplied output writer. </p> * * @param writer the writer to output XML to. * @param header comment to add at top of file * @throws <code>IOException</code> - when writing errors occur. */ public void store(Writer writer, String header) throws IOException { // Create a new JDOM Document with a root element "properties" Element root = new Element("properties"); Document doc = new Document(root); // Add in header information Comment comment = new Comment(header); doc.getContent().add(0, comment); // Get the property names Enumeration propertyNames = propertyNames(); while (propertyNames.hasMoreElements()) { String propertyName = (String) propertyNames.nextElement(); String propertyValue = getProperty(propertyName); createXMLRepresentation(root, propertyName, propertyValue); } // Output document to supplied filename XMLOutputter outputter = new XMLOutputter(" ", true); outputter.output(doc, writer); writer.flush(); } /** * <p> This will output the properties in this object * as XML to the supplied output stream. </p> * * @param out the output stream. * @param header comment to add at top of file * @throws <code>IOException</code> - when writing errors occur. */ public void store(OutputStream out, String header) throws IOException { store(new OutputStreamWriter(out), header); } /** * <p> This will output the properties in this object * as XML to the supplied output file. </p> * * @param xmlDocument XML file to output to. * @param header comment to add at top of file * @throws <code>IOException</code> - when writing errors occur. */ public void store(File xmlDocument, String header) throws IOException { store(new FileWriter(xmlDocument), header); } /** * <p> This will convert a single property and its value to * an XML element and textual value. </p> * * @param root JDOM root <code>Element</code> to add children to. * @param propertyName name to base element creation on. * @param propertyValue value to use for property. */ private void createXMLRepresentation(Element root, String propertyName, String propertyValue) { int split; String name = propertyName; Element current = root; Element test = null; while ((split = name.indexOf(".")) != -1) { String subName = name.substring(0, split); name = name.substring(split + 1); // Check for existing element if ((test = current.getChild(subName)) == null) { Element subElement = new Element(subName); current.addContent(subElement); current = subElement; } else { current = test; } } // When out of loop, what's left is the final element's name Element last = new Element(name); last.setText(propertyValue); /** Uncomment this for Attribute usage */ /* last.setAttribute("value", propertyValue); */ current.addContent(last); } } /*-- Copyright (C) 2001 Brett McLaughlin. 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 disclaimer that follows these conditions in the documentation and/or other materials provided with the distribution. 3. The name "Java and XML" must not be used to endorse or promote products derived from this software without prior written permission. For written permission, please contact brett@newInstance.com. In addition, we request (but do not require) that you include in the end-user documentation provided with the redistribution and/or in the software itself an acknowledgement equivalent to the following: "This product includes software developed for the 'Java and XML' book, by Brett McLaughlin (O'Reilly & Associates)." 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 JDOM AUTHORS OR THE PROJECT 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. */ /** * <b><code>TestXMLProperties</code></b> is a simple class that tests * usage of the <code>{@link XMLProperties}</code> class for reading * XML property files. */ class TestXMLProperties { /** * <p>Provide a static entry point for testing.</p> */ public static void main(String[] args) { if (args.length != 2) { System.out.println("Usage: java TestXMLProperties " + "[XML input document] [XML output document]"); System.exit(0); } try { // Create and load properties System.out.println("Reading XML properties from " + args[0]); XMLProperties props = new XMLProperties(); props.load(new FileInputStream(args[0])); // Print out properties and values System.out.println("\n\n---- Property Values ----"); Enumeration names = props.propertyNames(); while (names.hasMoreElements()) { String name = (String) names.nextElement(); String value = props.getProperty(name); System.out.println("Property Name: " + name + " has value " + value); } // Store properties System.out.println("\n\nWriting XML properies to " + args[1]); props.store(new FileOutputStream(args[1]), "Testing XMLProperties class"); } catch (Exception e) { e.printStackTrace(); } } } // Demo file: enhydra.properties /* # # This file has several Enhydra-specific properties # to make available to Java programs running with # knowledge of this properties file. # # sax parser implementing class org.xml.sax.parser="org.apache.xerces.parsers.SAXParser" # Class used to start the server org.enhydra.initialclass=org.enhydra.multiServer.bootstrap.Bootstrap # initial arguments passed to the server org.enhydra.initialargs="./bootstrap.conf" # Classpath for the parent top enhydra classloader org.enhydra.classpath="." # separator for the classpath above org.enhydra.classpath.separator=":" */