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| |
| <document> |
| |
| <properties> |
| <title>Commons SCXML Usage - API notes - Engine</title> |
| <author email="commons-dev@jakarta.apache.org">Commons Documentation Team</author> |
| </properties> |
| |
| <body> |
| |
| <section name="Commons SCXML - Creating and configuring the SCXML engine"> |
| |
| <p>The Commons SCXML executor is the engine that runs the state machine. |
| Commons SCXML also allows listeners to be added to the |
| <code>SCXMLExecutor</code>, which are informed about the progress of |
| the state machine via <code>onEntry</code> and <code>onExit</code> |
| notifications for <code>TransitionTarget</code>s, as well as |
| <code>onTransition</code> notificatins when transitions are followed.</p> |
| |
| <subsection name="Usage"> |
| <p>The <code>SCXMLExecutor</code> is usually initialized as follows:</p> |
| <pre> |
| //import org.apache.commons.scxml.Context; |
| //import org.apache.commons.scxml.ErrorReporter; |
| //import org.apache.commons.scxml.Evaluator; |
| //import org.apache.commons.scxml.EventDispatcher; |
| //import org.apache.commons.scxml.SCXMLExecutor; |
| //import org.apache.commons.scxml.SCXMLListener; |
| //import org.apache.commons.scxml.model.SCXML; |
| //import org.apache.commons.scxml.model.ModelException; |
| |
| SCXMLExecutor exec = null; |
| try { |
| exec = new SCXMLExecutor(<Evaluator>, |
| <EventDispatcher>, <ErrorReporter>); |
| exec.setStateMachine(<SCXML>); |
| exec.addListener(<SCXML>, <SCXMLListener>); |
| exec.setRootContext(<Context>); |
| exec.setSuperStep(true); |
| exec.go(); |
| } catch (ModelException me) { |
| // Executor initialization failed, because the |
| // state machine specified has inconsistencies |
| } |
| </pre> |
| |
| <p>Commons SCXML provides basic implementations of the |
| <code>EventDispatcher</code>, <code>ErrorReporter</code>, and |
| <code>SCXMLListener</code> interfaces, which simply log |
| all the events received. Commons SCXML uses Commons Logging.</p> |
| |
| <p>The SCXML specification allows implementations to support multiple |
| expression languages so SCXML documents can be used in varying |
| environments. The <code>Context</code> and <code>Evaluator</code> |
| interfaces serve as adapters to the particular expression language |
| APIs. Commons SCXML currently supports JEXL and JSP 2.0 EL |
| expressions.</p> |
| |
| <p>The <code>SCXMLExecutor</code> Javadoc is available |
| <a href="../apidocs/org/apache/commons/scxml/SCXMLExecutor.html"> |
| here</a>. |
| </p> |
| </subsection> |
| |
| <subsection name="API notes set"> |
| <p>The previous note in this set describes the |
| <a href="core-digester.html">SCXML digester</a>.<br/> |
| The next note in this set describes |
| <a href="core-events.html">triggering events</a>.</p> |
| </subsection> |
| |
| </section> |
| |
| </body> |
| |
| </document> |
