Author: buildbot
Date: Wed Mar 27 22:19:01 2013
New Revision: 856214
Log:
Production update by buildbot for camel
Modified:
websites/production/camel/content/cache/main.pageCache
websites/production/camel/content/guava-eventbus.html
Modified: websites/production/camel/content/cache/main.pageCache
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Binary files - no diff available.
Modified: websites/production/camel/content/guava-eventbus.html
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--- websites/production/camel/content/guava-eventbus.html (original)
+++ websites/production/camel/content/guava-eventbus.html Wed Mar 27 22:19:01
2013
@@ -147,6 +147,43 @@ eventBus.register(<span class="code-keyw
}
});
</pre>
+</div></div>
+
+<h3><a shape="rect" name="GuavaEventBus-DeadEventconsiderations"></a>DeadEvent
considerations</h3>
+
+<p>Keep in mind that due to the limitations caused by the design of the Guava
EventBus, you cannot specify event class to be received by the listener without
creating class annotated with <tt>@Subscribe</tt> method. This limitation
implies that endpoint with <tt>eventClass</tt> option specified actually
listens to all possible events (<tt>java.lang.Object</tt>) and filter
appropriate messages programmatically at runtime. The snipped below
demonstrates an appropriate excerpt from the Camel code base.</p>
+
+<div class="code panel" style="border-width: 1px;"><div class="codeContent
panelContent">
+<pre class="code-java">
+@Subscribe
+<span class="code-keyword">public</span> void eventReceived(<span
class="code-object">Object</span> event) {
+ <span class="code-keyword">if</span> (eventClass == <span
class="code-keyword">null</span> ||
eventClass.isAssignableFrom(event.getClass())) {
+ doEventReceived(event);
+...
+</pre>
+</div></div>
+
+<p>This drawback of this approach is that <tt>EventBus</tt> instance used by
Camel will never generate <tt>com.google.common.eventbus.DeadEvent</tt>
notifications. If you want Camel to listen only to the precisely specified
event (and therefore enable <tt>DeadEvent</tt> support), use
<tt>listenerInterface</tt> endpoint option. Camel will create dynamic proxy
over the interface you specify with the latter option and listen only to
messages specified by the interface handler methods. The example of the
listener interface with single method handling only <tt>SpecificEvent</tt>
instances is demonstrated below.</p>
+
+<div class="code panel" style="border-width: 1px;"><div class="codeContent
panelContent">
+<pre class="code-java">
+<span class="code-keyword">package</span> com.example;
+
+<span class="code-keyword">public</span> <span
class="code-keyword">interface</span> CustomListener {
+
+ @Subscribe
+ void eventReceived(SpecificEvent event);
+
+}
+</pre>
+</div></div>
+
+<p>The listener presented above could be used in the endpoint definition as
follows.</p>
+
+<div class="code panel" style="border-width: 1px;"><div class="codeContent
panelContent">
+<pre class="code-java">
+from(<span
class="code-quote">"guava-eventbus:busName?listenerInterface=com.example.CustomListener"</span>).to(<span
class="code-quote">"seda:queue"</span>);
+</pre>
</div></div></div>
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