Wiki source code of Local Observation Module
Last modified by Clemens Robbenhaar on 2015/06/19 18:07
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| author | version | line-number | content |
|---|---|---|---|
| 1 | {{box cssClass="floatinginfobox" title="**Contents**"}} | ||
| 2 | {{toc/}} | ||
| 3 | {{/box}} | ||
| 4 | |||
| 5 | Provides the ability to listen to internal XWiki events such as events when document change, when an action is executed, etc. | ||
| 6 | |||
| 7 | {{warning}} | ||
| 8 | TODO: Add architecture diagram here | ||
| 9 | {{/warning}} | ||
| 10 | |||
| 11 | = Features = | ||
| 12 | |||
| 13 | * Supports any kind of event, including custom events | ||
| 14 | * API to listen to a particular event type | ||
| 15 | * API to listen to any event type | ||
| 16 | * API to register event listeners | ||
| 17 | ** Automatically as component | ||
| 18 | ** Programmatically | ||
| 19 | * API to unregister event listeners programmatically | ||
| 20 | * API to send events to all listeners | ||
| 21 | |||
| 22 | = Examples = | ||
| 23 | |||
| 24 | See this [[Writing an Event Listener Tutorial>>platform:DevGuide.WritingEventListenerTutorial]]. | ||
| 25 | |||
| 26 | {{toc scope="local"/}} | ||
| 27 | |||
| 28 | == Consuming and producing events == | ||
| 29 | |||
| 30 | Observe **document save events** in the wiki, and fire a custom **user created** event when the saved document is a user document. | ||
| 31 | |||
| 32 | The first class is the event listener, the second defines the custom event itself. | ||
| 33 | |||
| 34 | Since 5.4 an ##org.xwiki.observation.AbstractEventListener## is provided. | ||
| 35 | |||
| 36 | {{code language="java"}} | ||
| 37 | package com.example; | ||
| 38 | |||
| 39 | import java.util.Arrays; | ||
| 40 | import java.util.HashMap; | ||
| 41 | import java.util.List; | ||
| 42 | import java.util.Map; | ||
| 43 | |||
| 44 | import javax.inject.Inject; | ||
| 45 | import javax.inject.Named; | ||
| 46 | |||
| 47 | import org.xwiki.bridge.event.DocumentCreatedEvent; | ||
| 48 | import org.xwiki.bridge.event.DocumentDeletedEvent; | ||
| 49 | import org.xwiki.bridge.event.DocumentUpdatedEvent; | ||
| 50 | import org.xwiki.component.annotation.Component; | ||
| 51 | import org.xwiki.component.manager.ComponentLookupException; | ||
| 52 | import org.xwiki.component.manager.ComponentManager; | ||
| 53 | import org.xwiki.model.reference.DocumentReference; | ||
| 54 | import org.xwiki.observation.EventListener; | ||
| 55 | import org.xwiki.observation.ObservationManager; | ||
| 56 | import org.xwiki.observation.event.Event; | ||
| 57 | |||
| 58 | import com.xpn.xwiki.doc.XWikiDocument; | ||
| 59 | |||
| 60 | import com.example.event.UserCreationEvent; | ||
| 61 | |||
| 62 | @Component | ||
| 63 | @Named("usercreation") | ||
| 64 | public class UserCreationEventListener extends AbstractEventListener | ||
| 65 | { | ||
| 66 | @Inject | ||
| 67 | private ComponentManager componentManager; | ||
| 68 | |||
| 69 | /** | ||
| 70 | * The observation manager that will be use to fire user creation events. Note: We can't have the OM as a | ||
| 71 | * requirement, since it would create an infinite initialization loop, causing a stack overflow error (this event | ||
| 72 | * listener would require an initialized OM and the OM requires a list of initialized event listeners) | ||
| 73 | */ | ||
| 74 | private ObservationManager observationManager; | ||
| 75 | |||
| 76 | public UserCreationEventListener() | ||
| 77 | { | ||
| 78 | super("usercreation", new DocumentCreatedEvent()); | ||
| 79 | } | ||
| 80 | |||
| 81 | /** | ||
| 82 | * {@inheritDoc} | ||
| 83 | */ | ||
| 84 | public void onEvent(Event event, Object source, Object data) | ||
| 85 | { | ||
| 86 | XWikiDocument document = (XWikiDocument) source; | ||
| 87 | String wikiName = document.getDocumentReference().getWikiReference().getName(); | ||
| 88 | DocumentReference userClass = new DocumentReference(wikiName, "XWiki", "XWikiUsers"); | ||
| 89 | |||
| 90 | if (document.getXObject(userClass) != null) { | ||
| 91 | // Create a map to hold our new event data | ||
| 92 | Map<String,String> userData = new HashMap<String,String>(); | ||
| 93 | userData.put("firstName", document.getXObject(userClass).getStringValue("firstName")); | ||
| 94 | userData.put("lastName", document.getXObject(userClass).getStringValue("lastName")); | ||
| 95 | userData.put("email", document.getXObject(userClass).getStringValue("email")); | ||
| 96 | // Fire the user created event | ||
| 97 | UserCreatedEvent newEvent = new UserCreationEvent(); | ||
| 98 | getObservationManager().notify(newEvent, source, userData); | ||
| 99 | } | ||
| 100 | } | ||
| 101 | |||
| 102 | private ObservationManager getObservationManager() | ||
| 103 | { | ||
| 104 | if (this.observationManager == null) { | ||
| 105 | try { | ||
| 106 | this.observationManager = componentManager.getInstance(ObservationManager.class); | ||
| 107 | } catch (ComponentLookupException e) { | ||
| 108 | throw new RuntimeException("Cound not retrieve an Observation Manager against the component manager"); | ||
| 109 | } | ||
| 110 | } | ||
| 111 | return this.observationManager; | ||
| 112 | } | ||
| 113 | |||
| 114 | } | ||
| 115 | {{/code}} | ||
| 116 | |||
| 117 | Here is an example before 5.4: | ||
| 118 | |||
| 119 | {{code language="java"}} | ||
| 120 | package com.example; | ||
| 121 | |||
| 122 | import java.util.Arrays; | ||
| 123 | import java.util.HashMap; | ||
| 124 | import java.util.List; | ||
| 125 | import java.util.Map; | ||
| 126 | |||
| 127 | import javax.inject.Inject; | ||
| 128 | import javax.inject.Named; | ||
| 129 | |||
| 130 | import org.xwiki.bridge.event.DocumentCreatedEvent; | ||
| 131 | import org.xwiki.bridge.event.DocumentDeletedEvent; | ||
| 132 | import org.xwiki.bridge.event.DocumentUpdatedEvent; | ||
| 133 | import org.xwiki.component.annotation.Component; | ||
| 134 | import org.xwiki.component.manager.ComponentLookupException; | ||
| 135 | import org.xwiki.component.manager.ComponentManager; | ||
| 136 | import org.xwiki.model.reference.DocumentReference; | ||
| 137 | import org.xwiki.observation.EventListener; | ||
| 138 | import org.xwiki.observation.ObservationManager; | ||
| 139 | import org.xwiki.observation.event.Event; | ||
| 140 | |||
| 141 | import com.xpn.xwiki.doc.XWikiDocument; | ||
| 142 | |||
| 143 | import com.example.event.UserCreationEvent; | ||
| 144 | |||
| 145 | @Component | ||
| 146 | @Named("usercreation") | ||
| 147 | public class UserCreationEventListener implements EventListener | ||
| 148 | { | ||
| 149 | @Inject | ||
| 150 | private ComponentManager componentManager; | ||
| 151 | |||
| 152 | /** | ||
| 153 | * The observation manager that will be use to fire user creation events. Note: We can't have the OM as a | ||
| 154 | * requirement, since it would create an infinite initialization loop, causing a stack overflow error (this event | ||
| 155 | * listener would require an initialized OM and the OM requires a list of initialized event listeners) | ||
| 156 | */ | ||
| 157 | private ObservationManager observationManager; | ||
| 158 | |||
| 159 | /** | ||
| 160 | * {@inheritDoc} | ||
| 161 | */ | ||
| 162 | public List<Event> getEvents() | ||
| 163 | { | ||
| 164 | return Arrays.<Event>asList(new DocumentCreatedEvent()); | ||
| 165 | } | ||
| 166 | |||
| 167 | /** | ||
| 168 | * {@inheritDoc} | ||
| 169 | */ | ||
| 170 | public String getName() | ||
| 171 | { | ||
| 172 | return "usercreation"; | ||
| 173 | } | ||
| 174 | |||
| 175 | /** | ||
| 176 | * {@inheritDoc} | ||
| 177 | */ | ||
| 178 | public void onEvent(Event event, Object source, Object data) | ||
| 179 | { | ||
| 180 | XWikiDocument document = (XWikiDocument) source; | ||
| 181 | String wikiName = document.getDocumentReference().getWikiReference().getName(); | ||
| 182 | DocumentReference userClass = new DocumentReference(wikiName, "XWiki", "XWikiUsers"); | ||
| 183 | |||
| 184 | if (document.getXObject(userClass) != null) { | ||
| 185 | // Create a map to hold our new event data | ||
| 186 | Map<String,String> userData = new HashMap<String,String>(); | ||
| 187 | userData.put("firstName", document.getXObject(userClass).getStringValue("firstName")); | ||
| 188 | userData.put("lastName", document.getXObject(userClass).getStringValue("lastName")); | ||
| 189 | userData.put("email", document.getXObject(userClass).getStringValue("email")); | ||
| 190 | // Fire the user created event | ||
| 191 | UserCreatedEvent newEvent = new UserCreationEvent(); | ||
| 192 | getObservationManager().notify(newEvent, source, userData); | ||
| 193 | } | ||
| 194 | } | ||
| 195 | |||
| 196 | private ObservationManager getObservationManager() | ||
| 197 | { | ||
| 198 | if (this.observationManager == null) { | ||
| 199 | try { | ||
| 200 | this.observationManager = componentManager.getInstance(ObservationManager.class); | ||
| 201 | |||
| 202 | } catch (ComponentLookupException e) { | ||
| 203 | throw new RuntimeException("Cound not retrieve an Observation Manager against the component manager"); | ||
| 204 | } | ||
| 205 | } | ||
| 206 | return this.observationManager; | ||
| 207 | } | ||
| 208 | |||
| 209 | } | ||
| 210 | {{/code}} | ||
| 211 | |||
| 212 | Definition of the custom event: | ||
| 213 | |||
| 214 | {{code language="java"}} | ||
| 215 | package com.example.event; | ||
| 216 | |||
| 217 | import org.xwiki.bridge.event.AbstractDocumentEvent; | ||
| 218 | import org.xwiki.observation.event.Event; | ||
| 219 | import org.xwiki.observation.event.filter.EventFilter; | ||
| 220 | |||
| 221 | /** | ||
| 222 | * {@link Event} generated when a new user is created. | ||
| 223 | */ | ||
| 224 | public class UserCreationEvent extends AbstractDocumentEvent | ||
| 225 | { | ||
| 226 | /** | ||
| 227 | * The version identifier for this Serializable class. Increment only if the <i>serialized</i> form of the class | ||
| 228 | * changes. | ||
| 229 | */ | ||
| 230 | private static final long serialVersionUID = 1L; | ||
| 231 | |||
| 232 | /** | ||
| 233 | * Constructor initializing the event filter with an | ||
| 234 | * {@link org.xwiki.observation.event.filter.AlwaysMatchingEventFilter}, meaning that this event will match any | ||
| 235 | * other document update event. | ||
| 236 | */ | ||
| 237 | public UserCreatedEvent() | ||
| 238 | { | ||
| 239 | super(); | ||
| 240 | } | ||
| 241 | |||
| 242 | /** | ||
| 243 | * Constructor initializing the event filter with a {@link org.xwiki.observation.event.filter.FixedNameEventFilter}, | ||
| 244 | * meaning that this event will match only update events affecting the document matching the passed document name. | ||
| 245 | * | ||
| 246 | * @param documentName the name of the updated document to match | ||
| 247 | */ | ||
| 248 | public UserCreatedEvent(String documentName) | ||
| 249 | { | ||
| 250 | super(documentName); | ||
| 251 | } | ||
| 252 | |||
| 253 | /** | ||
| 254 | * Constructor using a custom {@link EventFilter}. | ||
| 255 | * | ||
| 256 | * @param eventFilter the filter to use for matching events | ||
| 257 | */ | ||
| 258 | public UserCreatedEvent(EventFilter eventFilter) | ||
| 259 | { | ||
| 260 | super(eventFilter); | ||
| 261 | } | ||
| 262 | } | ||
| 263 | {{/code}} | ||
| 264 | |||
| 265 | == Writing an Event Listener in Groovy in a Wiki page == | ||
| 266 | |||
| 267 | See the [[tutorial>>platform:DevGuide.WritingEventListenerTutorial||anchor="HAddingcontenttopagesonsave"]]. | ||
| 268 | |||
| 269 | == Writing an Event Listener in Velocity in a Wiki page == | ||
| 270 | |||
| 271 | The [[documentation of the wiki components>>Extension.WikiComponent Module]] contains, as an example, the creation of an Event Listener. | ||
| 272 | |||
| 273 | == Fold events == | ||
| 274 | |||
| 275 | An event tagged as "Fold" can be sent by a task that generates some events during its execution. Then, these generated events can be seen as children of the main task. In addition, the [[Activity Stream>>Extension.Activity Stream Plugin]] will not record these child events. | ||
| 276 | |||
| 277 | This is an example of a custom fold event: | ||
| 278 | |||
| 279 | {{code language="java"}} | ||
| 280 | package org.xwiki.bridge.event; | ||
| 281 | |||
| 282 | import org.xwiki.observation.event.BeginFoldEvent; | ||
| 283 | |||
| 284 | public class MyTaskBeginEvent extends AbstractDocumentEvent implements BeginFoldEvent | ||
| 285 | { | ||
| 286 | /** | ||
| 287 | * The version identifier for this Serializable class. Increment only if the <i>serialized</i> form of the class | ||
| 288 | * changes. | ||
| 289 | */ | ||
| 290 | private static final long serialVersionUID = 1L; | ||
| 291 | |||
| 292 | /** | ||
| 293 | * Constructor initializing the event filter with an | ||
| 294 | * {@link org.xwiki.observation.event.filter.AlwaysMatchingEventFilter}, meaning that this event will match any | ||
| 295 | * other document update event. | ||
| 296 | */ | ||
| 297 | public MyTaskBeginEvent() | ||
| 298 | { | ||
| 299 | super(); | ||
| 300 | } | ||
| 301 | |||
| 302 | /** | ||
| 303 | * Constructor initializing the event filter with a {@link org.xwiki.observation.event.filter.FixedNameEventFilter}, | ||
| 304 | * meaning that this event will match only update events affecting the document matching the passed document name. | ||
| 305 | * | ||
| 306 | * @param documentName the name of the updated document to match | ||
| 307 | */ | ||
| 308 | public MyTaskBeginEvent(String documentName) | ||
| 309 | { | ||
| 310 | super(documentName); | ||
| 311 | } | ||
| 312 | |||
| 313 | /** | ||
| 314 | * Constructor using a custom {@link EventFilter}. | ||
| 315 | * | ||
| 316 | * @param eventFilter the filter to use for matching events | ||
| 317 | */ | ||
| 318 | public MyTaskBeginEvent(EventFilter eventFilter) | ||
| 319 | { | ||
| 320 | super(eventFilter); | ||
| 321 | } | ||
| 322 | } | ||
| 323 | {{/code}} | ||
| 324 | |||
| 325 | Then you need to define the corresponding {{code}}EndFoldEvent{{/code}} : | ||
| 326 | |||
| 327 | {{code language="java"}} | ||
| 328 | package org.xwiki.bridge.event; | ||
| 329 | |||
| 330 | import org.xwiki.observation.event.EndFoldEvent; | ||
| 331 | |||
| 332 | public class MyTaskEndEvent implements EndFoldEvent | ||
| 333 | { | ||
| 334 | /** | ||
| 335 | * The version identifier for this Serializable class. Increment only if the <i>serialized</i> form of the class | ||
| 336 | * changes. | ||
| 337 | */ | ||
| 338 | private static final long serialVersionUID = 1L; | ||
| 339 | |||
| 340 | /** | ||
| 341 | * Constructor initializing the event filter with an | ||
| 342 | * {@link org.xwiki.observation.event.filter.AlwaysMatchingEventFilter}, meaning that this event will match any | ||
| 343 | * other document update event. | ||
| 344 | */ | ||
| 345 | public MyTaskEndEvent() | ||
| 346 | { | ||
| 347 | super(); | ||
| 348 | } | ||
| 349 | |||
| 350 | /** | ||
| 351 | * Constructor initializing the event filter with a {@link org.xwiki.observation.event.filter.FixedNameEventFilter}, | ||
| 352 | * meaning that this event will match only update events affecting the document matching the passed document name. | ||
| 353 | * | ||
| 354 | * @param documentName the name of the updated document to match | ||
| 355 | */ | ||
| 356 | public MyTaskEndEvent(String documentName) | ||
| 357 | { | ||
| 358 | super(documentName); | ||
| 359 | } | ||
| 360 | |||
| 361 | /** | ||
| 362 | * Constructor using a custom {@link EventFilter}. | ||
| 363 | * | ||
| 364 | * @param eventFilter the filter to use for matching events | ||
| 365 | */ | ||
| 366 | public MyTaskEndEvent(EventFilter eventFilter) | ||
| 367 | { | ||
| 368 | super(eventFilter); | ||
| 369 | } | ||
| 370 | } | ||
| 371 | {{/code}} |
