fop/lib/Xslt.java

/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 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
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 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
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 * ====================================================================
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 * This software consists of voluntary contributions made by many
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 */
        
//package org.apache.tools.ant.taskdefs;

import org.apache.tools.ant.Task;
import java.net.*;
import java.io.*;
import org.apache.xalan.xslt.*;

/**
 * Task to call the XSLT processor Xalan (part of xml.apache.org), which converts xml files  
 * from a source to an output using a stylesheet file
 * 
 * <p>
 * This task can take the following arguments:
 * <ul>
 * <li>infile
 * <li>xsltfile
 * <li>outfile
 * <li>smart
 * </ul>
 * <p>  
 * Of these arguments, <b>infile, outfile</b> and <b>xsltfile</b> are required.
 * smart defaults to 'no'. The other allowed value is 'yes'. If smart is set to 'yes'
 * xalan is only called if either the outfile is older than the infile or the stylesheet
 * or the outfile doesn't exist.
 * <p>
 * @author Fotis Jannidis <a href="mailto:fotis@jannidis.de">fotis@jannidis.de</a>
 */


public class Xslt extends Task {
        private String infile, outfile, xsltfile;
        private String smart = "no";  //defaults to do conversion everytime task is called


    /**
     * Calls Xalan and does the transformation
     *
     */

        private void transform(String xmlSourceURL, String xslURL, String outputURL)
                                                throws java.io.IOException, 
                                                           java.net.MalformedURLException, 
                                                           org.xml.sax.SAXException {
                                          
                // Use XSLTProcessor to instantiate an XSLTProcessor.
                org.apache.xalan.xslt.XSLTProcessor processor =
                                           org.apache.xalan.xslt.XSLTProcessorFactory.getProcessor();
                                           
                // Create the 3 objects the XSLTProcessor needs to perform the transformation.
                org.apache.xalan.xslt.XSLTInputSource xmlSource = 
                                                          new org.apache.xalan.xslt.XSLTInputSource (infile);
                org.apache.xalan.xslt.XSLTInputSource xslSheet = 
                                                         new org.apache.xalan.xslt.XSLTInputSource (xsltfile);
                org.apache.xalan.xslt.XSLTResultTarget xmlResult = 
                                                         new org.apache.xalan.xslt.XSLTResultTarget (outfile);

                // Perform the transformation.
                System.out.println("============================");
                System.out.println("xslt \nin: " + infile + "\nstyle: " + xsltfile + "\nout: " + outfile);
                System.out.println("============================");
                processor.process(xmlSource, xslSheet, xmlResult);

        }
        
    /**
     * Sets the input file
     *
     */
        public void setInfile (String infile) {
                this.infile = infile;
        }

    /**
     * Sets the stylesheet file
     *
     */
        public void setXsltfile (String xsltfile) {
                this.xsltfile = xsltfile;
        }
        
    /**
     * Sets the output file
     *
     */
        public void setOutfile (String outfile) {
                this.outfile = outfile;
        }
        
    /**
     * Sets the value for smart 
     *
     * @param option valid values:
     * <ul>
     * <li>yes: check whether output file is older than input or stylesheet
     * <li>no: (default) do conversion everytime task is called
     * </ul>
     */
        public void setSmart (String smart) {
                this.smart = smart;
        }
        

    /**
     *  Catches the errors transform() can throw and 
     *  returns meaningfull error messages
     */
        private void startTransform () {
                try {
                        transform (infile,xsltfile,outfile);    
                } catch (org.xml.sax.SAXException saxerror) {
                        System.out.println("SAX Error: " + saxerror);
                } catch (MalformedURLException urlerror) {
                        System.out.println("URL Error: " + urlerror);                           
                } catch (IOException ioerror) {
                        System.out.println("IO Error: " + ioerror);             
                }
        }
        
    /**
     *  Main method, which is called by ant. 
     *  Checks for the value of smart and calls startTransform accordingly
     */
        public void execute () throws org.apache.tools.ant.BuildException {
                if (smart.equals("no")) {
                        startTransform();
                } else if (smart.equals("yes")) {
                        File outfileF = new File (outfile);
                        //checks for existence of output file
                        if (outfileF.exists()) {
                                //checks whether output file is older than input file or xslt stylesheet file
                                if ((outfileF.lastModified() < new File(infile).lastModified()) | (outfileF.lastModified() < new
File(xsltfile).lastModified())) {
                                        startTransform();       
                                } 
                        } else {
                                startTransform();
                        }
                //returns error message, if smart has another value as 'yes' or 'no'
                } else {
                        System.err.println("Error: Allowed values for the attribute smart are 'yes' or 'no'");
                }
                
        }
        //quick access for debugging    
        //usage XSLT infile xsltfile outfile (smart is 'yes') 
        /*
        public static void main (String args[]) {
                Xslt xslt = new Xslt();
                xslt.setInfile(args[0]);
                xslt.setXsltfile(args[1]);
                xslt.setOutfile(args[2]);
                xslt.setSmart("yes");
                xslt.execute();
        } 
        */
        
}