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diff --git a/site/trunk/site-publish/java-implementation-model-for-event-processing.html b/site/trunk/site-publish/java-implementation-model-for-event-processing.html new file mode 100644 index 0000000000..f1e560b58a --- /dev/null +++ b/site/trunk/site-publish/java-implementation-model-for-event-processing.html @@ -0,0 +1,207 @@ + +<!-- + + Licensed to the Apache Software Foundation (ASF) under one or more + contributor license agreements. See the NOTICE file distributed with + this work for additional information regarding copyright ownership. + The ASF licenses this file to You under the Apache License, Version 2.0 + (the "License"); you may not use this file except in compliance with + the License. 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All the standard SCA Java implementation features continue to be available to Java implementations. The following features are added:</P> +<UL> + <LI>Ability to define one or more methods of the implementation class to be <B><EM>consumer methods</EM></B>, consuming one or more <B><EM>event types</EM></B></LI> + <LI>Ability to define a field or setter method of the implementation class as an event <B><EM>producer</EM></B>, with one or more business methods producing one or more <B><EM>event types </EM></B></LI> + <LI>Ability to define <B><EM>event types</EM></B> as Java POJO classes</LI> +</UL> + + +<H2><A name="JavaImplementationModelforEventProcessing-EventTypes"></A>Event Types</H2> + +<P>Event types are defined through Java classes which are annotated with a @EventType annotation. The @EventType annotation has a single parameter which is the <B><EM>name</EM></B> of the event type.</P> +<DIV class="code panel" style="border-width: 1px;"><DIV class="codeContent panelContent"> +<PRE class="code-java">@EventType(ExampleEvent) +<SPAN class="code-keyword">public</SPAN> class ExampleEvent { + + <SPAN class="code-keyword">public</SPAN> <SPAN class="code-object">String</SPAN> eventData; + +} <SPAN class="code-comment">// end class ExampleEvent</SPAN> +</PRE> +</DIV></DIV> +<P>The name may be:</P> +<UL> + <LI><B><EM>unqualified</EM></B>, in which case the EventType name is qualified by the package name of the class itself</LI> + <LI><B><EM>qualified</EM></B>, in which case the EventType name is used as it is declared</LI> +</UL> + + +<P>Note that the Event Type name maps to an XSD QName using the Java-to-WSDL mapping as defined by JAX-WS.</P> + +<P>The Event type(s) handled by a consumer method or a producer method is defined in one of two ways:</P> +<OL> + <LI>The method has a parameter that is of a class annotated with the @EventType annotation (of a single event type)</LI> + <LI>The method is itself annotated with the @EventTypes annotation for one or more event types - where the method parameter is of some generic type such as java.lang.Object which does not specify an EventType</LI> +</OL> + + +<H2><A name="JavaImplementationModelforEventProcessing-EventConsumermethods"></A>Event Consumer methods</H2> + +<P>Each method of the implementation that is a consumer for events is annotated with a @Consumer annotation. Each method must have a <B><EM>void</EM></B> return type and a single parameter that is either a specific event type or a superclass of one or more event types, including java.lang.Object, which is treated as the supertype of all event types.</P> +<DIV class="code panel" style="border-width: 1px;"><DIV class="codeContent panelContent"> +<PRE class="code-java"><SPAN class="code-keyword">public</SPAN> class ConsumerrExample { + + <SPAN class="code-keyword">private</SPAN> ExampleProducer eventProducer; + + @Consumer(ExampleConsumer) + <SPAN class="code-keyword">public</SPAN> void someBusinessMethod( ExampleEvent theEvent ) { + <SPAN class="code-object">String</SPAN> businessData = theEvent.eventData; + <SPAN class="code-comment">// <SPAN class="code-keyword">do</SPAN> business processing... +</SPAN> } <SPAN class="code-comment">// end method someBusinessMethod +</SPAN> +} <SPAN class="code-comment">// end class</SPAN> +</PRE> +</DIV></DIV> + +<H2><A name="JavaImplementationModelforEventProcessing-EventProducers"></A>Event Producers</H2> + +<P>Event Producers are identified as a Field or a Setter method annotated with a @Producer annotation</P> + +<P>It is required that the Field or Setter method is typed by a Java interface. The Java interface must have one or more methods, each of which has a <B><EM>void</EM></B> return type and a single parameter that is either a specific event type or a superclass of one or more event types, including java.lang.Object, which is treated as the supertype of all event types.</P> +<DIV class="code panel" style="border-width: 1px;"><DIV class="codeContent panelContent"> +<PRE class="code-java">@Remotable +<SPAN class="code-keyword">public</SPAN> <SPAN class="code-keyword">interface</SPAN> ExampleProducer { + + void produceExampleEvent( ExampleEvent theEvent); + +} <SPAN class="code-comment">// end <SPAN class="code-keyword">interface</SPAN> ExampleProducer +</SPAN> +@EventType(ExampleEvent) +<SPAN class="code-keyword">public</SPAN> class ExampleEvent { + + <SPAN class="code-keyword">public</SPAN> <SPAN class="code-object">String</SPAN> eventData; + +} <SPAN class="code-comment">// end class ExampleEvent +</SPAN> + +<SPAN class="code-keyword">public</SPAN> class ProducerExample { + + <SPAN class="code-keyword">private</SPAN> ExampleProducer eventProducer; + + @Producer(ExampleEvent) + <SPAN class="code-keyword">public</SPAN> void setEventProducer( ExampleProducer theProducer ) { + eventProducer = theProducer; + <SPAN class="code-keyword">return</SPAN>; + } <SPAN class="code-comment">// end method setEventProducer +</SPAN> + <SPAN class="code-keyword">public</SPAN> void someBusinessMethod() { + theEvent = <SPAN class="code-keyword">new</SPAN> ExampleEvent(); + theEvent.eventData = <SPAN class="code-quote">"Some Data"</SPAN>; + eventProducer.produceExampleEvent( theEvent ); + } <SPAN class="code-comment">// end method someBusinessMethod +</SPAN> +} <SPAN class="code-comment">// end class</SPAN> +</PRE> +</DIV></DIV> + </DIV> + </DIV> + </DIV> + <!-- pageContent macro end --> + + </TD> + </TR> + </TABLE> + + <!-- footer macro --> + <SCRIPT src="http://www.google-analytics.com/urchin.js" type="text/javascript"> + </SCRIPT> + <SCRIPT type="text/javascript"> + _uacct = "UA-1174707-5"; + urchinTracker(); + </SCRIPT> + + <A href="http://www.statcounter.com/" target="_blank"><IMG src="http://c26.statcounter.com/counter.php?sc_project=2619156&java=0&security=94bd7e7d&invisible=0" alt="website stats" border="0"></A> + + <DIV class="footer"> + Copyright � 2003-2012, The Apache Software Foundation </BR> + Apache Tuscany and the Apache Tuscany project logo are trademarks of The Apache Software Foundation. + </DIV> + <!-- footer macro end --> + + </BODY> +</HTML> |