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
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
|
/*
* Copyright 2013 Decebal Suiu
*
* 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.
*/
package ro.fortsoft.pf4j;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* The default implementation for ExtensionFinder.
* All extensions declared in a plugin are indexed in a file "META-INF/extensions.idx".
* This class lookup extensions in all extensions index files "META-INF/extensions.idx".
*
* @author Decebal Suiu
*/
public class DefaultExtensionFinder implements ExtensionFinder, PluginStateListener {
private static final Logger log = LoggerFactory.getLogger(DefaultExtensionFinder.class);
protected PluginManager pluginManager;
protected ExtensionFactory extensionFactory;
protected volatile Map<String, Set<String>> entries; // cache by pluginId
public DefaultExtensionFinder(PluginManager pluginManager, ExtensionFactory extensionFactory) {
this.pluginManager = pluginManager;
this.extensionFactory = extensionFactory;
}
@Override
public <T> List<ExtensionWrapper<T>> find(Class<T> type) {
log.debug("Checking extension point '{}'", type.getName());
if (!isExtensionPoint(type)) {
log.warn("'{}' is not an extension point", type.getName());
return Collections.emptyList(); // or return null ?!
}
log.debug("Finding extensions for extension point '{}'", type.getName());
Map<String, Set<String>> entries = getEntries();
List<ExtensionWrapper<T>> result = new ArrayList<>();
for (Map.Entry<String, Set<String>> entry : entries.entrySet()) {
String pluginId = entry.getKey();
if (pluginId != null) {
PluginWrapper pluginWrapper = pluginManager.getPlugin(pluginId);
if (PluginState.STARTED != pluginWrapper.getPluginState()) {
continue;
}
}
for (String className : entry.getValue()) {
try {
ClassLoader classLoader;
if (pluginId != null) {
classLoader = pluginManager.getPluginClassLoader(pluginId);
} else {
classLoader = getClass().getClassLoader();
}
log.debug("Loading class '{}' using class loader '{}'", className, classLoader);
Class<?> extensionClass = classLoader.loadClass(className);
log.debug("Checking extension type '{}'", className);
if (type.isAssignableFrom(extensionClass) && extensionClass.isAnnotationPresent(Extension.class)) {
Extension extension = extensionClass.getAnnotation(Extension.class);
ExtensionDescriptor descriptor = new ExtensionDescriptor();
descriptor.setOrdinal(extension.ordinal());
descriptor.setExtensionClass(extensionClass);
ExtensionWrapper extensionWrapper = new ExtensionWrapper<>(descriptor);
extensionWrapper.setExtensionFactory(extensionFactory);
result.add(extensionWrapper);
log.debug("Added extension '{}' with ordinal {}", className, extension.ordinal());
} else {
log.debug("'{}' is not an extension for extension point '{}'", className, type.getName());
}
} catch (ClassNotFoundException e) {
log.error(e.getMessage(), e);
}
}
}
if (entries.isEmpty()) {
log.debug("No extensions found for extension point '{}'", type.getName());
} else {
log.debug("Found {} extensions for extension point '{}'", result.size(), type.getName());
}
// sort by "ordinal" property
Collections.sort(result);
return result;
}
@Override
public Set<String> findClassNames(String pluginId) {
return getEntries().get(pluginId);
}
@Override
public void pluginStateChanged(PluginStateEvent event) {
// TODO optimize (do only for some transitions)
// clear cache
entries = null;
}
protected Map<String, Set<String>> readIndexFiles() {
Map<String, Set<String>> result = new LinkedHashMap<>();
result.putAll(readClasspathIndexFiles());
result.putAll(readPluginsIndexFiles());
return result;
}
private Map<String, Set<String>> readClasspathIndexFiles() {
log.debug("Reading extensions index files from classpath");
Map<String, Set<String>> result = new LinkedHashMap<>();
Set<String> bucket = new HashSet<>();
try {
Enumeration<URL> urls = getClass().getClassLoader().getResources(ExtensionsIndexer.EXTENSIONS_RESOURCE);
while (urls.hasMoreElements()) {
URL url = urls.nextElement();
log.debug("Read '{}'", url.getFile());
Reader reader = new InputStreamReader(url.openStream(), "UTF-8");
ExtensionsIndexer.readIndex(reader, bucket);
}
if (bucket.isEmpty()) {
log.debug("No extensions found");
} else {
log.debug("Found possible {} extensions:", bucket.size());
for (String entry : bucket) {
log.debug(" " + entry);
}
}
result.put(null, bucket);
} catch (IOException e) {
log.error(e.getMessage(), e);
}
return result;
}
private Map<String, Set<String>> readPluginsIndexFiles() {
log.debug("Reading extensions index files from plugins");
Map<String, Set<String>> result = new LinkedHashMap<>();
List<PluginWrapper> plugins = pluginManager.getPlugins();
for (PluginWrapper plugin : plugins) {
String pluginId = plugin.getDescriptor().getPluginId();
log.debug("Reading extensions index file for plugin '{}'", pluginId);
Set<String> bucket = new HashSet<>();
try {
URL url = plugin.getPluginClassLoader().getResource(ExtensionsIndexer.EXTENSIONS_RESOURCE);
if (url != null) {
log.debug("Read '{}'", url.getFile());
Reader reader = new InputStreamReader(url.openStream(), "UTF-8");
ExtensionsIndexer.readIndex(reader, bucket);
} else {
log.debug("Cannot find '{}'", ExtensionsIndexer.EXTENSIONS_RESOURCE);
}
if (bucket.isEmpty()) {
log.debug("No extensions found");
} else {
log.debug("Found possible {} extensions:", bucket.size());
for (String entry : bucket) {
log.debug(" " + entry);
}
}
result.put(pluginId, bucket);
} catch (IOException e) {
log.error(e.getMessage(), e);
}
}
return result;
}
private boolean isExtensionPoint(Class<?> type) {
return ExtensionPoint.class.isAssignableFrom(type);
}
private Map<String, Set<String>> getEntries() {
if (entries == null) {
entries = readIndexFiles();
}
return entries;
}
}
|
