blob: 3d95d91a346f185fe18ec3ba47cb1066b7ed7e59 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
/*
* Copyright 2006 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* $Id$ */
package org.apache.fop.util;
import java.util.Iterator;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.xmlgraphics.util.Service;
/**
* This class holds references to various XML handlers used by FOP. It also
* supports automatic discovery of additional XML handlers available through
* the class path.
*/
public class ContentHandlerFactoryRegistry {
/** the logger */
private static Log log = LogFactory.getLog(ContentHandlerFactoryRegistry.class);
/** Map from namespace URIs to ContentHandlerFactories */
private Map factories = new java.util.HashMap();
/**
* Default constructor.
*/
public ContentHandlerFactoryRegistry() {
discover();
}
/**
* Add an XML handler. The handler itself is inspected to find out what it supports.
* @param classname the fully qualified class name
*/
public void addContentHandlerFactory(String classname) {
try {
ContentHandlerFactory factory
= (ContentHandlerFactory)Class.forName(classname).newInstance();
addContentHandlerFactory(factory);
} catch (ClassNotFoundException e) {
throw new IllegalArgumentException("Could not find "
+ classname);
} catch (InstantiationException e) {
throw new IllegalArgumentException("Could not instantiate "
+ classname);
} catch (IllegalAccessException e) {
throw new IllegalArgumentException("Could not access "
+ classname);
} catch (ClassCastException e) {
throw new IllegalArgumentException(classname
+ " is not an "
+ ContentHandlerFactory.class.getName());
}
}
/**
* Add an ContentHandlerFactory. The instance is inspected to find out what it supports.
* @param factory the ContentHandlerFactory instance
*/
public void addContentHandlerFactory(ContentHandlerFactory factory) {
String[] ns = factory.getSupportedNamespaces();
for (int i = 0; i < ns.length; i++) {
factories.put(ns[i], factory);
}
}
/**
* Retrieves a ContentHandlerFactory instance of a given namespace URI.
* @param namespaceURI the namespace to be handled.
* @return the ContentHandlerFactory or null, if no suitable instance is available.
*/
public ContentHandlerFactory getFactory(String namespaceURI) {
ContentHandlerFactory factory = (ContentHandlerFactory)factories.get(namespaceURI);
return factory;
}
/**
* Discovers ContentHandlerFactory implementations through the classpath and dynamically
* registers them.
*/
private void discover() {
// add mappings from available services
Iterator providers = Service.providers(ContentHandlerFactory.class);
if (providers != null) {
while (providers.hasNext()) {
ContentHandlerFactory factory = (ContentHandlerFactory)providers.next();
try {
if (log.isDebugEnabled()) {
log.debug("Dynamically adding ContentHandlerFactory: "
+ factory.getClass().getName());
}
addContentHandlerFactory(factory);
} catch (IllegalArgumentException e) {
log.error("Error while adding ContentHandlerFactory", e);
}
}
}
}
}
|
