1 /*
2 * Copyright 2010-2013 smartics, Kronseder & Reiner GmbH
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package de.smartics.xml.resolver;
17
18 import java.io.File;
19 import java.io.FileInputStream;
20 import java.io.IOException;
21
22 import org.xml.sax.EntityResolver;
23 import org.xml.sax.InputSource;
24 import org.xml.sax.SAXException;
25
26 /**
27 * Resolves the resource either as a file URL or relative to the given class in
28 * the class path.
29 *
30 * @author <a href="mailto:robert.reiner@smartics.de">Robert Reiner</a>
31 * @version $Revision:591 $
32 */
33 public class FileEntityResolver implements EntityResolver
34 {
35 // ********************************* Fields *********************************
36
37 // --- constants ------------------------------------------------------------
38
39 // --- members --------------------------------------------------------------
40
41 /**
42 * The delegate to pass to if this resolver is not responsible. May be
43 * <code>null</code>.
44 */
45 private final EntityResolver parentEntityResolver;
46
47 // ****************************** Initializer *******************************
48
49 // ****************************** Constructors ******************************
50
51 /**
52 * Default constructor.
53 *
54 * @param parentEntityResolver the delegate to pass to if this resolver is not
55 * responsible. May be <code>null</code>.
56 */
57 public FileEntityResolver(final EntityResolver parentEntityResolver)
58 {
59 this.parentEntityResolver = parentEntityResolver;
60 }
61
62 // ****************************** Inner Classes *****************************
63
64 // ********************************* Methods ********************************
65
66 // --- init -----------------------------------------------------------------
67
68 // --- get&set --------------------------------------------------------------
69
70 // --- business -------------------------------------------------------------
71
72 /**
73 * Resolves the resource either as a file URL or relative to the given class
74 * in the class path.
75 *
76 * @param publicId The public identifier of the external entity being
77 * referenced, or null if none was supplied.
78 * @param systemId The system identifier of the external entity being
79 * referenced.
80 * @return the input source for the public and system identifier.
81 * @throws org.xml.sax.SAXException Any SAX exception, possibly wrapping
82 * another exception.
83 * @throws java.io.IOException A Java-specific IO exception, possibly the
84 * result of creating a new InputStream or Reader for the
85 * InputSource.
86 */
87 @Override
88 public InputSource resolveEntity(final String publicId, final String systemId)
89 throws IOException, SAXException
90 {
91 if (systemId != null && systemId.startsWith("file:/"))
92 {
93 final File file = new File(systemId.substring(6));
94 if (file.canRead())
95 {
96 final InputSource source = new InputSource(new FileInputStream(file));
97 source.setPublicId(publicId);
98 source.setSystemId(systemId);
99 return source;
100 }
101 else
102 {
103 if (parentEntityResolver != null)
104 {
105 final String id = file.getName();
106 final InputSource source =
107 parentEntityResolver.resolveEntity(publicId, id);
108 source.setPublicId(publicId);
109 source.setSystemId(systemId);
110 return source;
111 }
112 }
113 }
114
115 if (parentEntityResolver != null)
116 {
117 return parentEntityResolver.resolveEntity(publicId, systemId);
118 }
119 else
120 {
121 throw new IOException("Cannot resolve " + publicId + " / " + systemId
122 + '.');
123 }
124 }
125
126 // --- object basics --------------------------------------------------------
127
128 }