JsfELExpressionParser and supporting classes for SWF-301, making JSF-managed beans available to expressions in the FlowDefinition via the unified EL.

2007-07-31 23:33:22 +00:00
parent 50c5174729
commit 99416e44ba
3 changed files with 220 additions and 0 deletions
--- a/spring-webflow/src/main/java/org/springframework/webflow/executor/jsf/ELResolverAdapter.java
+++ b/spring-webflow/src/main/java/org/springframework/webflow/executor/jsf/ELResolverAdapter.java
@@ -0,0 +1,132 @@
+package org.springframework.webflow.executor.jsf;
+
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+import javax.el.ELContext;
+import javax.el.ELException;
+import javax.el.ELResolver;
+import javax.el.PropertyNotWritableException;
+import javax.faces.context.FacesContext;
+import javax.faces.el.EvaluationException;
+import javax.faces.el.PropertyNotFoundException;
+import javax.faces.el.PropertyResolver;
+import javax.faces.el.VariableResolver;
+
+/**
+ * An adapter for using JSF 1.1 {@link VariableResolver}s and {@link PropertyResolver}s in an {@link ELContext}.
+ * @author Jeremy Grelle
+ * 
+ */
+public class ELResolverAdapter extends ELResolver {
+
+    private FacesContext facesContext;
+
+    public ELResolverAdapter(FacesContext facesContext) {
+	this.facesContext = facesContext;
+    }
+
+    public Class getCommonPropertyType(ELContext context, Object base) {
+	return Object.class;
+    }
+
+    public Iterator getFeatureDescriptors(ELContext context, Object base) {
+	return Collections.EMPTY_LIST.iterator();
+    }
+
+    public Class getType(ELContext context, Object base, Object property) {
+	if (property == null) {
+	    return null;
+	}
+	try {
+	    context.setPropertyResolved(true);
+	    if (base == null) {
+		Object var = getVariableResolver().resolveVariable(facesContext, property.toString());
+		return (var != null) ? var.getClass() : null;
+	    } else {
+		if (base instanceof List || base.getClass().isArray()) {
+		    return getPropertyResolver().getType(base, Integer.parseInt(property.toString()));
+		} else {
+		    return getPropertyResolver().getType(base, property);
+		}
+	    }
+	} catch (PropertyNotFoundException ex) {
+	    throw new javax.el.PropertyNotFoundException(ex.getMessage(), ex.getCause());
+	} catch (EvaluationException ex) {
+	    throw new ELException(ex.getMessage(), ex.getCause());
+	}
+    }
+
+    public Object getValue(ELContext context, Object base, Object property) {
+	if (property == null) {
+	    return null;
+	}
+	try {
+	    context.setPropertyResolved(true);
+	    if (base == null) {
+		return getVariableResolver().resolveVariable(facesContext, property.toString());
+	    } else {
+		if (base instanceof List || base.getClass().isArray()) {
+		    return getPropertyResolver().getValue(base, Integer.parseInt(property.toString()));
+		} else {
+		    return getPropertyResolver().getValue(base, property);
+		}
+	    }
+	} catch (PropertyNotFoundException ex) {
+	    throw new javax.el.PropertyNotFoundException(ex.getMessage(), ex.getCause());
+	} catch (EvaluationException ex) {
+	    throw new ELException(ex.getMessage(), ex.getCause());
+	}
+    }
+
+    public boolean isReadOnly(ELContext context, Object base, Object property) {
+	if (property == null) {
+	    return true;
+	}
+	try {
+	    context.setPropertyResolved(true);
+	    if (base == null) {
+		return false; // VariableResolver provides no way to determine isReadOnly
+	    } else {
+		if (base instanceof List || base.getClass().isArray()) {
+		    return getPropertyResolver().isReadOnly(base, Integer.parseInt(property.toString()));
+		} else {
+		    return getPropertyResolver().isReadOnly(base, property);
+		}
+	    }
+	} catch (PropertyNotFoundException ex) {
+	    throw new javax.el.PropertyNotFoundException(ex.getMessage(), ex.getCause());
+	} catch (EvaluationException ex) {
+	    throw new ELException(ex.getMessage(), ex.getCause());
+	}
+    }
+
+    public void setValue(ELContext context, Object base, Object property, Object value) {
+	if (property == null) {
+	    throw new PropertyNotWritableException("Property is Null");
+	}
+	try {
+	    context.setPropertyResolved(true);
+	    if (base instanceof List || base.getClass().isArray()) {
+		getPropertyResolver().setValue(base, Integer.parseInt(property.toString()), value);
+	    } else {
+		getPropertyResolver().setValue(base, property, value);
+	    }
+
+	} catch (PropertyNotFoundException ex) {
+	    throw new javax.el.PropertyNotFoundException(ex.getMessage(), ex.getCause());
+	} catch (EvaluationException ex) {
+	    throw new ELException(ex.getMessage(), ex.getCause());
+	}
+    }
+
+    private VariableResolver getVariableResolver() {
+	return facesContext.getApplication().getVariableResolver();
+    }
+
+    private PropertyResolver getPropertyResolver() {
+	return facesContext.getApplication().getPropertyResolver();
+    }
+
+}
--- a/spring-webflow/src/main/java/org/springframework/webflow/executor/jsf/FacesAPI.java
+++ b/spring-webflow/src/main/java/org/springframework/webflow/executor/jsf/FacesAPI.java
@@ -0,0 +1,25 @@
+package org.springframework.webflow.executor.jsf;
+
+import javax.faces.application.Application;
+
+public class FacesAPI {
+
+    private static final int version = specifyVersion();
+
+    private FacesAPI() {
+
+    }
+
+    private final static int specifyVersion() {
+	try {
+	    Application.class.getMethod("getExpressionFactory", null);
+	} catch (NoSuchMethodException e) {
+	    return 11;
+	}
+	return 12;
+    }
+
+    public final static int getVersion() {
+	return version;
+    }
+}
--- a/spring-webflow/src/main/java/org/springframework/webflow/executor/jsf/JsfELExpressionParser.java
+++ b/spring-webflow/src/main/java/org/springframework/webflow/executor/jsf/JsfELExpressionParser.java
@@ -0,0 +1,63 @@
+package org.springframework.webflow.executor.jsf;
+
+import javax.el.ELContext;
+import javax.el.ELResolver;
+import javax.el.FunctionMapper;
+import javax.el.VariableMapper;
+import javax.faces.context.FacesContext;
+
+import org.springframework.binding.expression.el.ELContextFactory;
+import org.springframework.binding.expression.el.JBossELExpressionParser;
+
+/**
+ * A JSF-aware ExpressionParser that allows JSF managed beans to be referenced in expressions in the FlowDefinition.
+ * @author Jeremy Grelle
+ * 
+ */
+public class JsfELExpressionParser extends JBossELExpressionParser {
+
+    public JsfELExpressionParser() {
+	super(new JsfELContextFactory());
+    }
+
+    public JsfELExpressionParser(ELContextFactory contextFactory) {
+	super(contextFactory);
+    }
+
+    private static class JsfELContextFactory implements ELContextFactory {
+
+	public ELContext getELContext(Object target) {
+
+	    FacesContext context = FacesContext.getCurrentInstance();
+	    if (FacesAPI.getVersion() < 12) {
+		return new Jsf11ELContext(context);
+	    }
+	    if (context != null) {
+		return context.getELContext();
+	    }
+	    return null;
+	}
+
+	private static class Jsf11ELContext extends ELContext {
+
+	    ELResolver baseResolver;
+
+	    public Jsf11ELContext(FacesContext context) {
+		baseResolver = new ELResolverAdapter(context);
+	    }
+
+	    public ELResolver getELResolver() {
+		return baseResolver;
+	    }
+
+	    public FunctionMapper getFunctionMapper() {
+		return null;
+	    }
+
+	    public VariableMapper getVariableMapper() {
+		return null;
+	    }
+	}
+    }
+
+}