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1 package org.objectweb.celtix.application;
2
3 import java.text.MessageFormat  ;
4 import java.util.ArrayList ;
5 import java.util.List ;
6 import java.util.logging.Level ;
7 import java.util.logging.Logger ;
8
9 import org.objectweb.celtix.common.i18n.Message;
10 import org.objectweb.celtix.common.logging.LogUtils;
11 import org.objectweb.celtix.configuration.Configuration;
12 import org.objectweb.celtix.plugins.PluginException;
13 import org.objectweb.celtix.plugins.PluginManager;
14
15
24 public class ApplicationPluginManager implements PluginManager {
25
26 private static final Logger LOG = LogUtils.getL7dLogger(ApplicationPluginManager.class);
27
28 private static final MessageFormat PLUGINS_CLASSNAME_FMT =
29 new MessageFormat ("plugins:{0}:className");
30
31 private static final MessageFormat PLUGINS_PREREQUISITES_FMT =
32 new MessageFormat ("plugins:{0}:prerequisites");
33
34 private final List <PluginInfo> plugins;
35
36 public ApplicationPluginManager() {
37 plugins = new ArrayList <PluginInfo>();
38 }
39
40
45 public Object getPlugin(String className) throws PluginException {
46 return getPlugin(null, className, null);
47 }
48
49
54 public Object getPluginByName(String pluginName) throws PluginException {
55 return getPluginByName(pluginName, null);
56 }
57
58
63 public synchronized void registerPlugin(Object plugin) throws PluginException {
64 PluginInfo info = findPluginInfo(plugin);
65 if (info.isRegisteredWith(this)) {
66 throw new PluginException(new Message("ALREADY_REGISTERED_EXC", LOG, info.getClassName()));
67 } else {
68 info.register(this);
69 }
70 }
71
72
77 public synchronized void unloadPlugin(Object plugin) throws PluginException {
78 PluginInfo info = findPluginInfo(plugin);
79 if (info.isRegistered()) {
80 throw new PluginException(new Message("STILL_REGISTERED_EXC", LOG, info.getClassName()));
81 } else {
82 plugins.remove(plugin);
83 info = null;
84 }
85 }
86
87
92 public synchronized void unregisterPlugin(Object plugin) throws PluginException {
93 PluginInfo info = findPluginInfo(plugin);
94 if (info.isRegisteredWith(this)) {
95 info.unregister(this);
96 } else {
97 throw new PluginException(new Message("NOT_REGISTERED_EXC", LOG, info.getClassName()));
98 }
99 }
100
101
106 public ClassLoader getPluginClassLoader() {
107 return getClass().getClassLoader();
108 }
109
110
113 public Configuration getConfiguration() {
114 return Application.getInstance().getConfiguration();
115 }
116
117 Object getPluginByName(String pluginName, PluginInfo dependent) throws PluginException {
118 String key = PLUGINS_CLASSNAME_FMT.format(pluginName);
119 Configuration configuration = getConfiguration();
120 String pluginClassName = (String )configuration.getObject(key);
121
122 return getPlugin(pluginName, pluginClassName, dependent);
123 }
124
125 Object getPlugin(String pluginName, String pluginClassName, PluginInfo dependent) throws PluginException {
126 LOG.entering(getClass().getName(), "getPlugin");
127 PluginInfo info = null;
128 PluginStateMachine state = null;
129 synchronized (this) {
130 info = findPluginByClassname(pluginClassName);
131 if (info == null) {
132 info = new PluginInfo(pluginClassName, this);
133 plugins.add(info);
134 }
135 state = info.getState();
136 if (PluginStateMachine.PluginState.LOADING == state.getCurrentState()) {
137 state.waitForState(PluginStateMachine.PluginState.LOADED);
138 LOG.exiting(getClass().getName(), "getPlugin", "object currently being loaded");
139 return info.getPlugin();
140 } else if (PluginStateMachine.PluginState.LOADED == state.getCurrentState()) {
141 LOG.exiting(getClass().getName(), "getPlugin", "object already loaded");
142 return info.getPlugin();
143 }
144 state.setNextState(PluginStateMachine.PluginState.LOADING);
145 }
146
147
149 if (dependent != null) {
150 info.setRequiredFor(dependent);
151 if (info.isCircularDependency()) {
152 throw new PluginException(new Message("CIRCULAR_DEPENDENCY_EXC", LOG, pluginClassName));
153 }
154 }
155
156 if (null != pluginName) {
157 Configuration configuration = getConfiguration();
158
159 String key = PLUGINS_PREREQUISITES_FMT.format(pluginName);
160 String [] prerequisites = (String [])configuration.getObject(key);
161
162 if (prerequisites != null) {
163 for (String p : prerequisites) {
164 getPluginByName(p, info);
165 }
166 }
167 }
168
169 Object plugin = createPlugin(pluginClassName);
170 info.setPlugin(plugin);
171 state.setNextState(PluginStateMachine.PluginState.LOADED);
172 LOG.exiting(getClass().getName(), "getPlugin", "object newly created");
173 return plugin;
174 }
175
176 Object createPlugin(String pluginClassName) throws PluginException {
177
178 ClassLoader cl = getPluginClassLoader();
179 Object plugin = null;
180 try {
181 Class <?> pluginClass = Class.forName(pluginClassName, true, cl);
182 plugin = pluginClass.newInstance();
183 } catch (Exception ex) {
184 LogUtils.log(LOG, Level.SEVERE, "PLUGIN_LOAD_FAILURE_MSG", ex, pluginClassName);
185 throw new PluginException(new Message("LOAD_FAILED_EXC", LOG, pluginClassName), ex);
186 }
187 return plugin;
188 }
189
190 PluginInfo findPluginByClassname(String className) {
191 for (PluginInfo info : plugins) {
192 if (info.getClassName().equals(className)
193 && info.getClassLoader() == getPluginClassLoader()) {
194 return info;
195 }
196 }
197 LOG.info("Could not find plugin info for class " + className);
198 return null;
199 }
200
201 PluginInfo findPluginInfo(Object plugin) {
202
203 for (PluginInfo info : plugins) {
204 if (plugin == info.getPlugin()) {
205 return info;
206 }
207 }
208 LOG.info("Could not find plugin info for plugin " + plugin);
209 return null;
210 }
211 }
212 |
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