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1
10 package org.mmbase.core.event;
11
12 import java.io.IOException  ;
13 import java.util.*;
14 import java.net.URL ;
15
16 import org.mmbase.util.*;
17 import org.mmbase.util.logging.Logger;
18 import org.mmbase.util.logging.Logging;
19 import org.mmbase.util.xml.DocumentReader;
20 import org.w3c.dom.Document ;
21 import org.w3c.dom.Element ;
22 import org.xml.sax.SAXException ;
23
24 import edu.emory.mathcs.backport.java.util.concurrent.CopyOnWriteArraySet;
25
26
34 public class EventManager {
35
36 private static final Logger log = Logging.getLoggerInstance(EventManager.class);
37
38 public static final String PUBLIC_ID_EVENTMANAGER = "-//MMBase//DTD eventmanager config 1.0//EN";
39 public static final String DTD_EVENTMANAGER = "eventmanager_1_0.dtd";
40
41
42 static {
43 org.mmbase.util.XMLEntityResolver.registerPublicID(PUBLIC_ID_EVENTMANAGER, DTD_EVENTMANAGER, EventManager.class);
44 }
45
46
49 private static final EventManager eventManager = new EventManager();
50
51
54 private final Set eventBrokers = new CopyOnWriteArraySet();
55
56 private long numberOfPropagatedEvents = 0;
57 private long duration = 0;
58
59
62 public static EventManager getInstance() {
63 return eventManager;
64 }
65
66 private static AbstractEventBroker findInstance(String className) {
67 if (className == null || "".equals(className)) return null;
68 try {
69 Class aClass = Class.forName(className);
70 return (AbstractEventBroker) aClass.newInstance();
71 } catch (ClassNotFoundException e) {
72 log.error("could not find class with name " + className, e);
73 } catch (InstantiationException e) {
74 log.error("could not instantiate class with name" + className, e);
75 } catch (IllegalAccessException e) {
76 log.error("the constructor of " + className + " is not accessible", e);
77 } catch (ClassCastException e) {
78 log.error("" + className + " is not a AbstratEventBroker");
79 }
80 return null;
81 }
82
83 protected ResourceWatcher watcher = new ResourceWatcher() {
84 public void onChange(String w) {
85 configure(w);
86 }
87 };
88
89 private EventManager() {
90 watcher.add("eventmanager.xml");
91 watcher.onChange();
92 watcher.start();
93 }
94
95
96 protected void configure(String resource) {
97 log.service("Configuring the event manager");
98 eventBrokers.clear();
99 Iterator i = ResourceLoader.getConfigurationRoot().getResourceList(resource).iterator();
100 while (i.hasNext()) {
101 URL url = (URL ) i.next();
102 try {
103 if (url.openConnection().getDoInput()) {
104
105 Document config = ResourceLoader.getDocument(url, true, EventManager.class);
106 DocumentReader configReader = new DocumentReader(config);
107
108 Iterator e = configReader.getChildElements("eventmanager.brokers", "broker");
110 while (e.hasNext()) {
111 Element element = (Element ) e.next();
112 String className = element.getAttribute("class");
113 AbstractEventBroker broker = (AbstractEventBroker) findInstance(className);
114 if (broker != null) {
115 if (log.isDebugEnabled()) {
116 log.debug("adding event broker: " + broker);
117 }
118 addEventBroker(broker);
119 }
120 }
121 }
122 } catch (SAXException e1) {
123 log.error("Something went wrong configuring the event system (" + url + "): " + e1.getMessage(), e1);
124 } catch (IOException e1) {
125 log.error("something went wrong configuring the event system (" + url + "): " + e1.getMessage(), e1);
126
127 }
128 }
129 if (eventBrokers.size() == 0) {
130 log.fatal("No event brokers could not be found. This means that query-invalidation does not work correctly now. Proceeding anyway.");
131 return;
132 }
133 }
134
138 public void addEventBroker(AbstractEventBroker broker) {
139 if(! eventBrokers.contains(broker)){
141 if (log.isDebugEnabled()) {
142 log.debug("adding broker " + broker.toString());
143 }
144 eventBrokers.add(broker);
145 } else {
146 if (log.isDebugEnabled()) {
147 log.debug("broker " + broker.toString() + "was already registered: rejected.");
148 }
149 }
150 }
151
152
156 public void removeEventBroker(AbstractEventBroker broker) {
157 eventBrokers.remove(broker);
158 }
159
160
163 public void addEventListener(EventListener listener) {
164 BrokerIterator i = findBrokers(listener);
165 while (i.hasNext()) {
166 AbstractEventBroker broker = i.nextBroker();
167 if (broker.addListener(listener)) {
168 if (log.isDebugEnabled()) {
169 log.debug("listener " + listener + " added to broker " + broker );
170 }
171 }
172 }
173 }
174
175
176
179 public void removeEventListener(EventListener listener) {
180 if (log.isDebugEnabled()) {
181 log.debug("removing listener of type: " + listener.getClass().getName());
182 }
183 BrokerIterator i = findBrokers(listener);
184 while (i.hasNext()) {
185 i.nextBroker().removeListener(listener);
186 }
187 }
188
189
196 public void propagateEvent(Event event) {
197 if (log.isTraceEnabled()) {
198 log.trace("Propagating events to " + eventBrokers);
199 }
200 long startTime = System.currentTimeMillis();
201 for (Iterator i = eventBrokers.iterator(); i.hasNext();) {
202 AbstractEventBroker broker = (AbstractEventBroker) i.next();
203 if (broker.canBrokerForEvent(event)) {
204 broker.notifyForEvent(event);
205 if (log.isDebugEnabled()) {
206 if (log.isTraceEnabled()) {
207 log.trace("event: " + event + " has been accepted by broker " + broker);
208 } else {
209 log.debug("event has been accepted by broker " + broker);
210 }
211 }
212 } else {
213 if (log.isDebugEnabled()) {
214 if (log.isTraceEnabled()) {
215 log.trace("event: " + event + " has been rejected by broker " + broker);
216 } else {
217 log.debug("event has been rejected by broker " + broker);
218 }
219 }
220 }
221 }
222 numberOfPropagatedEvents++;
223 duration += (System.currentTimeMillis() - startTime);
224 }
225
226
229 public long getNumberOfPropagatedEvents() {
230 return numberOfPropagatedEvents;
231 }
232
235 public long getPropagationCost() {
236 return duration;
237 }
238
239
240
243 private BrokerIterator findBrokers(final EventListener listener) {
244 if (log.isDebugEnabled()) {
245 log.debug("try to find broker for " + listener.getClass().getName());
246 }
247 return new BrokerIterator(eventBrokers.iterator(), listener);
248 }
249
250 private static class BrokerIterator implements Iterator {
251 AbstractEventBroker next;
252 final Iterator i;
253 final EventListener listener;
254
255 BrokerIterator(final Iterator i, final EventListener listener) {
256 this.i = i;
257 this.listener = listener;
258 findNext();
259 }
260 public void remove() {
261 throw new UnsupportedOperationException ();
262 }
263 public Object next() {
264 return nextBroker();
265 }
266 public boolean hasNext() {
267 return next != null;
268 }
269 public AbstractEventBroker nextBroker() {
270 if (next == null) throw new NoSuchElementException();
271 AbstractEventBroker n = next;
272 findNext();
273 return n;
274 }
275 protected void findNext() {
276 while(i.hasNext()) {
277 AbstractEventBroker broker = (AbstractEventBroker) i.next();
278 if (broker.canBrokerForListener(listener)) {
279 if (log.isDebugEnabled()) {
280 log.debug("broker " + broker + " can broker for eventlistener " + listener.getClass().getName());
281 }
282 next = broker;
283 return;
284 } else if (log.isDebugEnabled()) {
285 log.debug("broker " + broker + " cannot boker for eventlistener." + listener.getClass().getName());
286 }
287 }
288 next = null;
289 }
290
291 }
292
293
294
295 }
296 |
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