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Java > Open Source Codes > org > apache > batik > bridge > DocumentLoader


1 /*
2
3    Copyright 2000-2004 The Apache Software Foundation
4
5    Licensed under the Apache License, Version 2.0 (the "License");
6    you may not use this file except in compliance with the License.
7    You may obtain a copy of the License at
8
9        http://www.apache.org/licenses/LICENSE-2.0
10
11    Unless required by applicable law or agreed to in writing, software
12    distributed under the License is distributed on an "AS IS" BASIS,
13    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14    See the License for the specific language governing permissions and
15    limitations under the License.
16
17  */
18 package org.apache.batik.bridge;
19
20 import java.io.InputStream JavaDoc;
21 import java.io.IOException JavaDoc;
22 import java.util.HashMap JavaDoc;
23
24 import org.apache.batik.dom.svg.SAXSVGDocumentFactory;
25 import org.apache.batik.dom.svg.SVGDocumentFactory;
26 import org.apache.batik.dom.util.DocumentDescriptor;
27 import org.apache.batik.util.CleanerThread;
28
29 import org.w3c.dom.Document JavaDoc;
30 import org.w3c.dom.Element JavaDoc;
31 import org.w3c.dom.svg.SVGDocument;
32
33 /**
34  * This class is responsible on loading an SVG document and
35  * maintaining a cache.
36  *
37  * @author <a HREF="mailto:Thierry.Kormann@sophia.inria.fr">Thierry Kormann</a>
38  * @version $Id: DocumentLoader.java,v 1.23 2005/01/03 10:48:05 deweese Exp $
39  */
40 public class DocumentLoader {
41
42     /**
43      * The document factory used to create the document according a
44      * DOM implementation.
45      */
46     protected SVGDocumentFactory documentFactory;
47
48     /**
49      * The map that contains the Document indexed by the URI.
50      *
51      * WARNING: tagged private as no element of this Map should be
52      * referenced outise of this class
53      */
54     protected HashMap JavaDoc cacheMap = new HashMap JavaDoc();
55
56     /**
57      * The user agent.
58      */
59     protected UserAgent userAgent;
60
61     /**
62      * Constructs a new <tt>DocumentLoader</tt>.
63      */
64     protected DocumentLoader() { }
65
66     /**
67      * Constructs a new <tt>DocumentLoader</tt> with the specified XML parser.
68      * @param userAgent the user agent to use
69      */
70     public DocumentLoader(UserAgent userAgent) {
71         this.userAgent = userAgent;
72         documentFactory = new SAXSVGDocumentFactory
73             (userAgent.getXMLParserClassName(), true);
74     documentFactory.setValidating(userAgent.isXMLParserValidating());
75     }
76
77     public Document JavaDoc checkCache(String JavaDoc uri) {
78         int n = uri.lastIndexOf('/');
79         if (n == -1)
80             n = 0;
81         n = uri.indexOf('#', n);
82         if (n != -1) {
83             uri = uri.substring(0, n);
84         }
85         DocumentState state;
86         synchronized (cacheMap) {
87             state = (DocumentState)cacheMap.get(uri);
88         }
89         if (state != null)
90             return state.getDocument();
91         return null;
92     }
93
94     /**
95      * Returns a document from the specified uri.
96      * @param uri the uri of the document
97      * @exception IOException if an I/O error occured while loading
98      * the document
99      */
100     public Document JavaDoc loadDocument(String JavaDoc uri) throws IOException JavaDoc {
101         Document JavaDoc ret = checkCache(uri);
102         if (ret != null)
103             return ret;
104
105         SVGDocument document = documentFactory.createSVGDocument(uri);
106
107         DocumentDescriptor desc = documentFactory.getDocumentDescriptor();
108         DocumentState state = new DocumentState(uri, document, desc);
109         synchronized (cacheMap) {
110             cacheMap.put(uri, state);
111         }
112
113         return state.getDocument();
114     }
115
116     /**
117      * Returns a document from the specified uri.
118      * @param uri the uri of the document
119      * @exception IOException if an I/O error occured while loading
120      * the document
121      */
122     public Document JavaDoc loadDocument(String JavaDoc uri, InputStream JavaDoc is)
123         throws IOException JavaDoc {
124         Document JavaDoc ret = checkCache(uri);
125         if (ret != null)
126             return ret;
127
128         SVGDocument document = documentFactory.createSVGDocument(uri, is);
129
130         DocumentDescriptor desc = documentFactory.getDocumentDescriptor();
131         DocumentState state = new DocumentState(uri, document, desc);
132         synchronized (cacheMap) {
133             cacheMap.put(uri, state);
134         }
135
136         return state.getDocument();
137     }
138
139     /**
140      * Returns the userAgent used by this DocumentLoader
141      */
142     public UserAgent getUserAgent(){
143         return userAgent;
144     }
145
146     /**
147      * Disposes and releases all resources allocated by this document loader.
148      */
149     public void dispose() {
150         // new Exception("purge the cache").printStackTrace();
151 synchronized (cacheMap) {
152             cacheMap.clear();
153         }
154     }
155
156     /**
157      * Returns the line in the source code of the specified element or
158      * -1 if not found.
159      *
160      * @param e the element
161      * @return -1 the document has been removed from the cache or has not
162      * been loaded by this document loader.
163      */
164     public int getLineNumber(Element JavaDoc e) {
165         String JavaDoc uri = ((SVGDocument)e.getOwnerDocument()).getURL();
166         DocumentState state;
167         synchronized (cacheMap) {
168             state = (DocumentState)cacheMap.get(uri);
169         }
170         if (state == null) {
171             return -1;
172         } else {
173             return state.desc.getLocationLine(e);
174         }
175     }
176
177     /**
178      * A simple class that contains a Document and its number of nodes.
179      */
180     private class DocumentState extends CleanerThread.SoftReferenceCleared {
181
182         private String JavaDoc uri;
183         private DocumentDescriptor desc;
184
185         public DocumentState(String JavaDoc uri,
186                              Document JavaDoc document,
187                              DocumentDescriptor desc) {
188             super(document);
189             this.uri = uri;
190             this.desc = desc;
191         }
192
193         public void cleared() {
194             synchronized (cacheMap) {
195                 cacheMap.remove(uri);
196             }
197         }
198
199         public DocumentDescriptor getDocumentDescriptor() {
200             return desc;
201         }
202
203         public String JavaDoc getURI() {
204             return uri;
205         }
206
207         public Document JavaDoc getDocument() {
208             return (Document JavaDoc)get();
209         }
210     }
211
212 }
213
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