Author: rahul
Date: Sat Oct 8 22:42:23 2005
New Revision: 307370
URL: http://svn.apache.org/viewcvs?rev=307370&view=rev
Log:
Exploring use of SCXML documents for describing Shale dialogs.
Added:
jakarta/commons/sandbox/scxml/trunk/src/main/java/org/apache/commons/scxml/env/faces/ShaleDialogELEvaluator.java
(with props)
Added:
jakarta/commons/sandbox/scxml/trunk/src/main/java/org/apache/commons/scxml/env/faces/ShaleDialogELEvaluator.java
URL:
http://svn.apache.org/viewcvs/jakarta/commons/sandbox/scxml/trunk/src/main/java/org/apache/commons/scxml/env/faces/ShaleDialogELEvaluator.java?rev=307370&view=auto
==============================================================================
---
jakarta/commons/sandbox/scxml/trunk/src/main/java/org/apache/commons/scxml/env/faces/ShaleDialogELEvaluator.java
(added)
+++
jakarta/commons/sandbox/scxml/trunk/src/main/java/org/apache/commons/scxml/env/faces/ShaleDialogELEvaluator.java
Sat Oct 8 22:42:23 2005
@@ -0,0 +1,154 @@
+/*
+ *
+ * Copyright 2005 The Apache Software Foundation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+package org.apache.commons.scxml.env.faces;
+
+import java.util.regex.Pattern;
+
+import javax.faces.context.FacesContext;
+import javax.faces.el.EvaluationException;
+import javax.faces.el.MethodBinding;
+import javax.faces.el.MethodNotFoundException;
+import javax.faces.el.ReferenceSyntaxException;
+
+import org.apache.commons.scxml.Context;
+import org.apache.commons.scxml.Evaluator;
+import org.apache.commons.scxml.SCXMLExpressionException;
+import org.apache.commons.scxml.env.jsp.ELEvaluator;
+
+/**
+ * <p>EL evaluator, for evaluating the expressions in SCXML documents used
+ * to specify Shale dialogs.</p>
+ *
+ * <p>This evaluator uses the following premises for evaluation:
+ * <ol>
+ * <li>JSF method binding expressions will take the form:
+ * #{...}
+ * These will return a <code>java.lang.String</code> object as
+ * required by the methods associated with
+ * <code>org.apache.shale.dialog.ActionState</code></li>
+ * <li>JSP 2.0 EL expressions will take the form:
+ * ${...}</li>
+ * </ol>
+ * </p>
+ *
+ * <p>This evaluator delegates to the following expression evaluators:
+ * <ol>
+ * <li>JSF method binding expressions get delegated to the JSF
+ * implementation (Ex: Apache MyFaces).</li>
+ * <li>JSP expressions get delegated to the Apache Jakarta Commons
+ * EL ExpressionEvaluator implementation. This evaluator adds
+ * ability to evaluate special predicates defined by SCXML.</li>
+ * </ol>
+ * </p>
+ */
+public class ShaleDialogELEvaluator extends ELEvaluator {
+
+ /**
+ * Shale ActionState method parameters.
+ *
+ * @see org.apache.shale.dialog.faces.DialogNavigationHandler.PARAMETERS
+ */
+ private static final Object[] PARAMETERS = new Object[0];
+ /**
+ * Shale ActionState method signature.
+ *
+ * @see org.apache.shale.dialog.faces.DialogNavigationHandler.SIGNATURE
+ */
+ private static final Class[] SIGNATURE = new Class[0];
+
+ // We do not have the privilege of having specific element attributes
+ // associated with specific types of expressions
+ /** Pattern for recognizing the method / value binding expression. */
+ private static Pattern jsfBindingExpr =
+ Pattern.compile("^\\s*#\\{.*\\}\\s*$");
+ /** FacesContext for this request. */
+ private FacesContext context;
+
+ /**
+ * Constructor.
+ */
+ public ShaleDialogELEvaluator() {
+ super();
+ }
+
+ /**
+ * Set per request context.
+ *
+ * @param context The FacesContext for this request.
+ */
+ public void setFacesContext(final FacesContext context) {
+ this.context = context;
+ }
+
+ /**
+ * Evaluate an expression.
+ *
+ * @param ctx variable context
+ * @param expr expression
+ * @return Object The result of the evaluation
+ * @throws SCXMLExpressionException For a malformed expression
+ * @see Evaluator#eval(Context, String)
+ */
+ public Object eval(final Context ctx, final String expr)
+ throws SCXMLExpressionException {
+ if (jsfBindingExpr.matcher(expr).matches()) {
+ return invokeShaleActionStateMethod(expr);
+ }
+ return super.eval(ctx, expr);
+ }
+
+ /**
+ * Evaluate a boolean expression.
+ *
+ * @param ctx variable context
+ * @param expr expression
+ * @return Boolean The result of the evaluation
+ * @throws SCXMLExpressionException For a malformed expression
+ * @see Evaluator#evalCond(Context, String)
+ */
+ public Boolean evalCond(final Context ctx, final String expr)
+ throws SCXMLExpressionException {
+ return super.evalCond(ctx, expr);
+ }
+
+ /**
+ * Invoke method binding expression for Shale <code>ActionState</code>.
+ * Shale requires return type to be a <code>java.lang.String</code>.
+ *
+ * @param expr Method binding expression
+ * @return String Method return value
+ * @throws SCXMLExpressionException Re-throw potential Faces
+ * exceptions as a SCXMLExpressionException.
+ */
+ private String invokeShaleActionStateMethod(final String expr)
+ throws SCXMLExpressionException {
+ try {
+ MethodBinding mb = context.getApplication().
+ createMethodBinding(expr, SIGNATURE);
+ return (String) mb.invoke(context, PARAMETERS);
+ } catch (ReferenceSyntaxException rse) {
+ throw new SCXMLExpressionException(rse);
+ } catch (MethodNotFoundException mnfe) {
+ throw new SCXMLExpressionException(mnfe);
+ } catch (EvaluationException ee) {
+ throw new SCXMLExpressionException(ee);
+ }
+ }
+
+}
+
Propchange:
jakarta/commons/sandbox/scxml/trunk/src/main/java/org/apache/commons/scxml/env/faces/ShaleDialogELEvaluator.java
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svn:eol-style = native
Propchange:
jakarta/commons/sandbox/scxml/trunk/src/main/java/org/apache/commons/scxml/env/faces/ShaleDialogELEvaluator.java
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