/*-- 

 Copyright (C) 2001-2004 Jason Hunter & 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 "JDOM" must not be used to endorse or promote products
    derived from this software without prior written permission.  For
    written permission, please contact license@jdom.org.
 
 4. Products derived from this software may not be called "JDOM", nor
    may "JDOM" appear in their name, without prior written permission
    from the JDOM Project Management (pm@jdom.org).
 
 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 by the
      JDOM Project (http://www.jdom.org/)."
 Alternatively, the acknowledgment may be graphical using the logos 
 available at http://www.jdom.org/images/logos.

 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.

 This software consists of voluntary contributions made by many 
 individuals on behalf of the JDOM Project and was originally 
 created by Jason Hunter <jhunter_AT_jdom_DOT_org> and
 Brett McLaughlin <brett_AT_jdom_DOT_org>.  For more information
 on the JDOM Project, please see <http://www.jdom.org/>.

 */

// Explicitly left in the default package

import java.io.*;
import java.util.*;
import java.util.jar.*;
import java.util.zip.*;

import org.jdom.*;
import org.jdom.input.*;

/**
 * This class is not part of the core JDOM API, but implements a way to show 
 * information about JDOM. 
 * To "run" this class directly use a command line such as the following:
 *
 * <pre>
 *   java -cp jdom.jar JDOMAbout 
 * </pre>
 *
 * When run like this, the output will display product and version information, 
 * a brief description of JDOM and the authors, all as specified in the file 
 * META-INF/jdom-info.xml contained within the JAR. If this file does not exist 
 * in the JAR, then the JAR has been incorrectly built. Any exceptions will pop 
 * the call stack and end the program with a message describing the error.
 *
 * @see http://java.sun.com/docs/books/tutorial/jar/
 *
 * @author Steven Gould <steven.gouldATcgiusa.com>
 * @author Victor Toni
 */
public class JDOMAbout {
    /**
     * The main method executed when this class is run.
     * <p>
     * Outputs information about the JAR, as extracted from the
     * META-INF/jdom-info.xml file.
     * </p>
     * 
     * @param args
     *            Ignored.
     */
    public static void main(final String args[]) throws Exception {
        final Info info = new Info();

        // Shortcut for info.title (because it's used so much)
        final String title = info.title;

        // Output product information
        System.out.println(title + " version " + info.version);
        System.out.println("Copyright " + info.copyright);
        System.out.println();
        
        // Display product/JAR "description"
        System.out.println(info.description);
        System.out.println();
        
        // Iterate through authors, outputting each in turn
        System.out.println("Authors:");
        for (final Iterator iter = info.authors.iterator(); iter.hasNext();) {
            final Author author = (Author) iter.next();
        
            // Output the author's name
            System.out.print("  " + author.name);
                
            // If the author has an e-mail address, output it too
            if (author.email == null) {
                System.out.println();
            } else {
                System.out.println(" <" + author.email + ">");
            }
        }
        System.out.println();
    
        // Display "license" information
        System.out.println(title + " license:");
        System.out.println(info.license);
        System.out.println();
    
        // Display "support" information
        System.out.println(title + " support:");
        System.out.println(info.support);
        System.out.println();
    
        // Display "license" information
        System.out.println(title + " web site: " + info.website);
        System.out.println();
    }

    /**
     * This class encapsulates the locating of, and reading of, the JAR
     * information file. This file should be named
     * <code>META-INF/jdom-info.xml</code>. The default constructor
     * initializes all members variables from the content of the
     * <code>META-INF/jdom-info.xml</code> file.
     * 
     * <p>
     * This class has been separated out for a couple of reasons:
     * <ol>
     * <li>So that the presentation of the data in jdom-info.xml can be
     * separated out from the reading of the file - enabling a "looser" coupling
     * between the data and presentation.</li>
     * <li>Just in case we later decide to make this information publically
     * accessible. If this happens we'll probably want to implement "get"
     * methods for each of the member variables. For now, it was decided that
     * doing so may be too much of an overhead for an internal class.</li>
     * </ol>
     */
    private static class Info {
        private static final String INFO_FILENAME = "META-INF/jdom-info.xml";


        /** The product title, or product name. */
        final String title;

        /**
         * The product/JAR version number - or string. This can contain
         * characters.
         */
        final String version;

        /** The JAR copyright message. */
        final String copyright;

        /** A description of the contents of this JAR. */
        final String description;

        /** The product/JAR license information. */
        final String license;

        /** Product/JAR support information. */
        final String support;

        /** The main web site for this product/JAR. */
        final String website;
    
        /** A list of authors of this product/JAR. */
        final List authors = new ArrayList();;

        /**
         * Constructor for the Info class - initializes all member variables
         * with values taken from the JAR information file. The JAR information
         * file should be called <code>META-INF/jdom-info.xml</code> and be
         * contained within the JAR file. Any exceptions are passed to the
         * caller.
         */
        Info() throws Exception {

            final InputStream inputStream = getInfoFileStream();
            
            final SAXBuilder builder = new SAXBuilder();
            
            // Using JDOM, read the jdom-info.xml file
            final Document doc = builder.build(inputStream);
            final Element root = doc.getRootElement();

            title = root.getChildTextTrim("title");
            version = root.getChildTextTrim("version");
            copyright = root.getChildTextTrim("copyright");
            description = root.getChildTextTrim("description");
            license = root.getChildTextTrim("license");
            support = root.getChildTextTrim("support");
            website = root.getChildTextTrim("web-site");

            final List authorElements = root.getChildren("author");
            for (final Iterator iter = authorElements.iterator(); iter.hasNext();) {
                final Element element = (Element) iter.next();
                    
                final Author author = new Author(
                    element.getChildTextTrim("name"),
                    element.getChildTextTrim("e-mail")
                );

                authors.add(author);
            }
        }

        private InputStream getInfoFileStream() throws FileNotFoundException {
            // Find the INFO_FILENAME file in the classpath 
            // and get input stream for reading the info file
            final InputStream inputStream = getClass().getResourceAsStream(INFO_FILENAME);

            if (inputStream == null) {
              throw new FileNotFoundException(INFO_FILENAME + 
                " not found; it should be within the JDOM JAR but wasn't found on the classpath");
            }

            return inputStream;
        }
    }

    /**
     * A helper class that stores information about a single Author. By
     * using this class, the Info class can store Author information
     * without any dependence on JDOM and XML elements.
     */
    private static class Author {
        /** The name of this author. */
        final String name;

        /** The e-mail address of this author. */
        final String email;

        Author(final String name, final String email) {
            this.name = name;
            this.email = email;
        }
    }
}