1 /**
   2  * AUTOHIT 2003
   3  * Copyright Erich P Gatejen (c) 1989,1997,2003,2004
   4  * 
   5  * This program is free software; you can redistribute it and/or modify 
   6  * it under the terms of the GNU General Public License as published by 
   7  * the Free Software Foundation; either version 2 of the License, or (at
   8  * your option) any later version.
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  11  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  12  * more details.
  13  * 
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17  *
  18  * Additional license information can be found in the documentation.
  19  * @author Erich P Gatejen
  20  */
  21 package autohit.creator.compiler;
  22 
  23 import java.io.StringReader;
  24 import java.util.Hashtable;
  25 
  26 import org.xml.sax.EntityResolver;
  27 import org.xml.sax.InputSource;
  28 import org.xml.sax.SAXException;
  29 import org.xml.sax.SAXNotSupportedException;
  30 
  31 import autohit.common.AutohitLogInjectorWrapper;
  32 
  33 /**
  34  * Implement our own resolver to handle XML activities.  
  35  * For the most part, this is used to provide DTDs.
  36  * <p>
  37  * The default constructor assumes you do not want to log.  If you use the other constructor, 
  38  * supply a valid CreatorLog and a log entry will be made for every resolve.
  39  * <p>
  40  * After construction, you need to register URIs to resolve.
  41  * If the resolver encounters any URIs that are not registered,
  42  * it will throw a SAXNotSupportedException exception.
  43  * 
  44  * In this version, we assume that are resources are Strings.
  45  * This should be easy to extend in the future.
  46  *
  47  * @author Erich P. Gatejen
  48  * @version 1.1
  49  * <i>Version History</i>
  50  * <code>EPG - Initial - 11Apr03</code> 
  51  * 
  52  */
  53 public class XmlCompilerResolver implements EntityResolver {
  54 
  55 	/**
  56 	 * Contains the registered entities.  Leave this a Hashtable,
  57 	 * since it should be syncronized.
  58 	 */
  59 	private Hashtable registeredEntities;
  60 
  61 	private AutohitLogInjectorWrapper log;
  62 
  63 	// --- PUBLIC METHODS ----------------------------------------------------	
  64 
  65 	/**
  66 	 *  Default constructor.
  67 	 */
  68 	XmlCompilerResolver() {
  69 		log = null;
  70 	}
  71 
  72 	/**
  73 	 *  Constructor.  This one sets a logger.
  74 	 *
  75 	 * @param cLog A reference to a valid, working CreatorLog.
  76 	 * @see autohit.creator.CreatorLog
  77 	 */
  78 	XmlCompilerResolver(AutohitLogInjectorWrapper cLog) {
  79 		log = cLog;
  80 	}
  81 
  82 	/**
  83 	 *  Register a resource as an entity.  The entity is the system URI and *not* the public name It will store the resource in the hashtable keyed on the entity..
  84 	 *
  85 	 *  @param uri A string containing the textual entity to trap and resolve.
  86 	 *  @param text A string containing actual resource.
  87 	 */
  88 	public void register(String uri, String text) {
  89 		if (registeredEntities == null) {
  90 			registeredEntities = new Hashtable();
  91 		}
  92 		registeredEntities.put(uri, text);
  93 	}
  94 
  95 	/**
  96 	 *  overrides the resolver.
  97 	 *
  98 	 *  @param name not implimented.
  99 	 *  @param uri Passed to this from the parser.  We will trap
 100 	 *                  the uri.
 101 	 *  @return an input source to be used by the XML parser.
 102 	 */
 103 	public InputSource resolveEntity(
 104 		java.lang.String name,
 105 		java.lang.String uri)
 106 		throws SAXException, java.io.IOException {
 107 
 108 		InputSource tis;
 109 
 110 		if (log != null)
 111 			log.debug(
 112 				"Resolve Entity: public=[" + name + "] system=[" + uri + "]");
 113 				
 114 		// strip the "//" crap we've added via the InputSource
 115 		uri = uri.substring(2, uri.length());
 116 		
 117 		// Is the entity registered?
 118 		if (registeredEntities.containsKey(uri)) {
 119 
 120 			tis =
 121 				new InputSource(
 122 					new StringReader((String) registeredEntities.get(uri)));
 123 
 124 		} else {
 125 			if (log != null)
 126 				log.debug("        ERROR: but it is not registered!");
 127 			throw new SAXNotSupportedException(
 128 				"URI [" + uri + "] not registered");
 129 		}
 130 
 131 		return tis;
 132 	}
 133 }