source: icXML/icXML-devel/src/xercesc/util/XMLEntityResolver.hpp @ 2722

Last change on this file since 2722 was 2722, checked in by cameron, 6 years ago

Original Xerces files with import mods for icxercesc

File size: 6.5 KB
Line 
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/*
19 * $Id: XMLEntityResolver.hpp 527149 2007-04-10 14:56:39Z amassari $
20 */
21
22#if !defined(XERCESC_INCLUDE_GUARD_XMLENTITYRESOLVER_HPP)
23#define XERCESC_INCLUDE_GUARD_XMLENTITYRESOLVER_HPP
24
25#include <xercesc/util/XercesDefs.hpp>
26#include <xercesc/util/XMemory.hpp>
27#include <xercesc/util/XMLResourceIdentifier.hpp>
28
29XERCES_CPP_NAMESPACE_BEGIN
30
31class InputSource;
32
33/**
34  * Revised interface for resolving entities.
35  *
36  * <p>If an application needs to implement customized handling
37  * for external entities, it can implement this interface and
38  * register an instance with the parser using the parser's
39  * setXMLEntityResolver method or it can use the basic SAX interface
40  * (EntityResolver).  The difference between the two interfaces is
41  * the arguments to the resolveEntity() method.  With the SAX
42  * EntityResolve the arguments are systemId and publicId.  With this
43  * interface the argument is a XMLResourceIdentifier object.  <i>Only
44  * one EntityResolver can be set using setEntityResolver() or
45  * setXMLEntityResolver, if both are set the last one set is
46  * used.</i></p>
47  *
48  * <p>The parser will then allow the application to intercept any
49  * external entities (including the external DTD subset and external
50  * parameter entities, if any) before including them.</p>
51  *
52  * <p>Many applications will not need to implement this interface,
53  * but it will be especially useful for applications that build
54  * XML documents from databases or other specialised input sources,
55  * or for applications that use URI types other than URLs.</p>
56  *
57  * <p>The following resolver would provide the application
58  * with a special character stream for the entity with the system
59  * identifier "http://www.myhost.com/today":</p>
60  *
61  *<code>
62  * \#include <xercesc/util/XMLEntityResolver.hpp><br>
63  * \#include <xercesc/sax/InputSource.hpp><br>
64  *<br>
65  *&nbsp;class MyResolver : public XMLEntityResolver {<br>
66  *&nbsp;&nbsp;public:<br>
67  *&nbsp;&nbsp;&nbsp;InputSource resolveEntity (XMLResourceIdentifier* xmlri);<br>
68  *&nbsp;&nbsp;&nbsp;...<br>
69  *&nbsp;&nbsp;};<br>
70  *<br>
71  *&nbsp;MyResolver::resolveEntity(XMLResourceIdentifier* xmlri) {<br>
72  *&nbsp;&nbsp;switch(xmlri->getResourceIdentifierType()) {<br>
73  *&nbsp;&nbsp;&nbsp;case XMLResourceIdentifier::SystemId:<br>
74  *&nbsp;&nbsp;&nbsp;&nbsp;if (XMLString::compareString(xmlri->getSystemId(), "http://www.myhost.com/today")) {<br>
75  *&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;MyReader* reader = new MyReader();<br>
76  *&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return new InputSource(reader);<br>
77  *&nbsp;&nbsp;&nbsp;&nbsp;} else {<br>
78  *&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return null;<br>
79  *&nbsp;&nbsp;&nbsp;&nbsp;}<br>
80  *&nbsp;&nbsp;&nbsp;&nbsp;break;<br>
81  *&nbsp;&nbsp;&nbsp;default:<br>
82  *&nbsp;&nbsp;&nbsp;&nbsp;return null;<br>
83  *&nbsp;&nbsp;}<br>
84  *&nbsp;}</code>
85  *
86  * <p>The application can also use this interface to redirect system
87  * identifiers to local URIs or to look up replacements in a catalog
88  * (possibly by using the public identifier).</p>
89  *
90  * <p>The HandlerBase class implements the default behaviour for
91  * this interface, which is simply always to return null (to request
92  * that the parser use the default system identifier).</p>
93  *
94  * @see XMLResourceIdentifier
95  * @see Parser#setXMLEntityResolver
96  * @see InputSource#InputSource
97  * @see HandlerBase#HandlerBase
98  */
99class XMLUTIL_EXPORT XMLEntityResolver
100{
101public:
102    /** @name Constructors and Destructor */
103    //@{
104
105
106    /** Destructor */
107    virtual ~XMLEntityResolver()
108    {
109    }
110
111    //@}
112
113    /** @name The XMLEntityResolver interface */
114    //@{
115
116  /**
117    * Allow the application to resolve external entities.
118    *
119    * <p>The Parser will call this method before opening any external
120    * entity except the top-level document entity (including the
121    * external DTD subset, external entities referenced within the
122    * DTD, and external entities referenced within the document
123    * element): the application may request that the parser resolve
124    * the entity itself, that it use an alternative URI, or that it
125    * use an entirely different input source.</p>
126    *
127    * <p>Application writers can use this method to redirect external
128    * system identifiers to secure and/or local URIs, to look up
129    * public identifiers in a catalogue, or to read an entity from a
130    * database or other input source (including, for example, a dialog
131    * box).</p>
132    *
133    * <p>If the system identifier is a URL, the SAX parser must
134    * resolve it fully before reporting it to the application.</p>
135    *
136    * @param resourceIdentifier An object containing the type of
137    *        resource to be resolved and the associated data members
138    *        corresponding to this type.
139    * @return An InputSource object describing the new input source,
140    *         or null to request that the parser open a regular
141    *         URI connection to the system identifier.
142    *         The returned InputSource is owned by the parser which is
143    *         responsible to clean up the memory.
144    * @exception SAXException Any SAX exception, possibly
145    *            wrapping another exception.
146    * @exception IOException An IO exception,
147    *            possibly the result of creating a new InputStream
148    *            or Reader for the InputSource.
149    *
150    * @see InputSource#InputSource
151    * @see XMLResourceIdentifier
152    */
153    virtual InputSource* resolveEntity
154    (
155        XMLResourceIdentifier* resourceIdentifier
156    ) = 0;
157
158    //@}
159protected: 
160    /** Default Constructor */
161    XMLEntityResolver()
162    {
163    }
164
165private :
166    /* Unimplemented constructors and operators */
167
168    /* Copy constructor */
169    XMLEntityResolver(const XMLEntityResolver&);
170
171    /* Assignment operator */
172    XMLEntityResolver& operator=(const XMLEntityResolver&);
173
174};
175
176XERCES_CPP_NAMESPACE_END
177
178#endif
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