1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. 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.xerces.util;
19
20 import java.io.InputStream;
21 import java.io.IOException;
22 import java.io.Reader;
23
24 import org.apache.xerces.xni.XNIException;
25 import org.apache.xerces.xni.XMLResourceIdentifier;
26 import org.apache.xerces.xni.parser.XMLEntityResolver;
27 import org.apache.xerces.xni.parser.XMLInputSource;
28
29 import org.xml.sax.EntityResolver;
30 import org.xml.sax.InputSource;
31 import org.xml.sax.SAXException;
32
33 /**
34 * This class wraps a SAX entity resolver in an XNI entity resolver.
35 *
36 * @see EntityResolver
37 *
38 * @author Andy Clark, IBM
39 *
40 * @version $Id: EntityResolverWrapper.java 447241 2006-09-18 05:12:57Z mrglavas $
41 */
42 public class EntityResolverWrapper
43 implements XMLEntityResolver {
44
45 //
46 // Data
47 //
48
49 /** The SAX entity resolver. */
50 protected EntityResolver fEntityResolver;
51
52 //
53 // Constructors
54 //
55
56 /** Default constructor. */
57 public EntityResolverWrapper() {}
58
59 /** Wraps the specified SAX entity resolver. */
60 public EntityResolverWrapper(EntityResolver entityResolver) {
61 setEntityResolver(entityResolver);
62 } // <init>(EntityResolver)
63
64 //
65 // Public methods
66 //
67
68 /** Sets the SAX entity resolver. */
69 public void setEntityResolver(EntityResolver entityResolver) {
70 fEntityResolver = entityResolver;
71 } // setEntityResolver(EntityResolver)
72
73 /** Returns the SAX entity resolver. */
74 public EntityResolver getEntityResolver() {
75 return fEntityResolver;
76 } // getEntityResolver():EntityResolver
77
78 //
79 // XMLEntityResolver methods
80 //
81
82 /**
83 * Resolves an external parsed entity. If the entity cannot be
84 * resolved, this method should return null.
85 *
86 * @param resourceIdentifier contains the physical co-ordinates of the resource to be resolved
87 *
88 * @throws XNIException Thrown on general error.
89 * @throws IOException Thrown if resolved entity stream cannot be
90 * opened or some other i/o error occurs.
91 */
92 public XMLInputSource resolveEntity(XMLResourceIdentifier resourceIdentifier)
93 throws XNIException, IOException {
94
95 // When both pubId and sysId are null, the user's entity resolver
96 // can do nothing about it. We'd better not bother calling it.
97 // This happens when the resourceIdentifier is a GrammarDescription,
98 // which describes a schema grammar of some namespace, but without
99 // any schema location hint. -Sg
100 String pubId = resourceIdentifier.getPublicId();
101 String sysId = resourceIdentifier.getExpandedSystemId();
102 if (pubId == null && sysId == null)
103 return null;
104
105 // resolve entity using SAX entity resolver
106 if (fEntityResolver != null && resourceIdentifier != null) {
107 try {
108 InputSource inputSource = fEntityResolver.resolveEntity(pubId, sysId);
109 if (inputSource != null) {
110 String publicId = inputSource.getPublicId();
111 String systemId = inputSource.getSystemId();
112 String baseSystemId = resourceIdentifier.getBaseSystemId();
113 InputStream byteStream = inputSource.getByteStream();
114 Reader charStream = inputSource.getCharacterStream();
115 String encoding = inputSource.getEncoding();
116 XMLInputSource xmlInputSource =
117 new XMLInputSource(publicId, systemId, baseSystemId);
118 xmlInputSource.setByteStream(byteStream);
119 xmlInputSource.setCharacterStream(charStream);
120 xmlInputSource.setEncoding(encoding);
121 return xmlInputSource;
122 }
123 }
124
125 // error resolving entity
126 catch (SAXException e) {
127 Exception ex = e.getException();
128 if (ex == null) {
129 ex = e;
130 }
131 throw new XNIException(ex);
132 }
133 }
134
135 // unable to resolve entity
136 return null;
137
138 } // resolveEntity(String,String,String):XMLInputSource
139 }
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