SWF-301 - Make JSF managed beans accessible inside a flow definition using EL expressions

spring-faces/src/main/java/org/springframework/faces/expression/LegacyJSFBeanResolver.java

@@ -0,0 +1,93 @@
+package org.springframework.faces.expression;
+
+import java.util.Iterator;
+
+import javax.el.ELContext;
+import javax.el.ELResolver;
+
+import org.springframework.webflow.execution.RequestContext;
+import org.springframework.webflow.execution.RequestContextHolder;
+
+/**
+ * ELResolver that checks request, session, and application scopes for existing JSF-managed beans. This allows
+ * traditional JSF-managed beans (defined in faces-config.xml) to be resolved through expressions in a flow definition.
+ * The preferred approach is to instead use Spring to configure such beans, but this is meant to ease migration for
+ * users with existing JSF artifacts. Note that this resolver does not have access to the JSF managed bean definitions
+ * and will not trigger the bean's instantiation if it has not already been initialized by JSF.
+ * 
+ * @author Jeremy Grelle
+ */
+public class LegacyJSFBeanResolver extends ELResolver {
+
+	public Class getCommonPropertyType(ELContext context, Object base) {
+		return Object.class;
+	}
+
+	public Iterator getFeatureDescriptors(ELContext context, Object base) {
+		return null;
+	}
+
+	public Class getType(ELContext context, Object base, Object property) {
+		if (base == null) {
+			RequestContext requestContext = RequestContextHolder.getRequestContext();
+			if (requestContext.getExternalContext().getRequestMap().contains(property.toString())) {
+				context.setPropertyResolved(true);
+				return requestContext.getExternalContext().getRequestMap().get(property.toString()).getClass();
+			} else if (requestContext.getExternalContext().getSessionMap().contains(property.toString())) {
+				context.setPropertyResolved(true);
+				return requestContext.getExternalContext().getSessionMap().get(property.toString()).getClass();
+			} else if (requestContext.getExternalContext().getApplicationMap().contains(property.toString())) {
+				context.setPropertyResolved(true);
+				return requestContext.getExternalContext().getApplicationMap().get(property.toString()).getClass();
+			}
+		}
+		return null;
+	}
+
+	public Object getValue(ELContext context, Object base, Object property) {
+		if (base == null) {
+			RequestContext requestContext = RequestContextHolder.getRequestContext();
+			if (requestContext.getExternalContext().getRequestMap().contains(property.toString())) {
+				context.setPropertyResolved(true);
+				return requestContext.getExternalContext().getRequestMap().get(property.toString());
+			} else if (requestContext.getExternalContext().getSessionMap().contains(property.toString())) {
+				context.setPropertyResolved(true);
+				return requestContext.getExternalContext().getSessionMap().get(property.toString());
+			} else if (requestContext.getExternalContext().getApplicationMap().contains(property.toString())) {
+				context.setPropertyResolved(true);
+				return requestContext.getExternalContext().getApplicationMap().get(property.toString());
+			}
+		}
+		return null;
+	}
+
+	public boolean isReadOnly(ELContext context, Object base, Object property) {
+		if (base == null) {
+			RequestContext requestContext = RequestContextHolder.getRequestContext();
+			if (requestContext.getExternalContext().getRequestMap().contains(property.toString())
+					|| requestContext.getExternalContext().getSessionMap().contains(property.toString())
+					|| requestContext.getExternalContext().getApplicationMap().contains(property.toString())) {
+				context.setPropertyResolved(true);
+				return true;
+			}
+		}
+		return false;
+	}
+
+	public void setValue(ELContext context, Object base, Object property, Object value) {
+		if (base == null) {
+			RequestContext requestContext = RequestContextHolder.getRequestContext();
+			if (requestContext.getExternalContext().getRequestMap().contains(property.toString())) {
+				context.setPropertyResolved(true);
+				requestContext.getExternalContext().getRequestMap().put(property.toString(), value);
+			} else if (requestContext.getExternalContext().getSessionMap().contains(property.toString())) {
+				context.setPropertyResolved(true);
+				requestContext.getExternalContext().getSessionMap().put(property.toString(), value);
+			} else if (requestContext.getExternalContext().getApplicationMap().contains(property.toString())) {
+				context.setPropertyResolved(true);
+				requestContext.getExternalContext().getApplicationMap().put(property.toString(), value);
+			}
+		}
+	}
+
+}

spring-faces/src/main/java/org/springframework/faces/expression/LegacyJSFELExpressionParser.java

@@ -0,0 +1,73 @@
+package org.springframework.faces.expression;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.el.ELContext;
+import javax.el.ELResolver;
+import javax.el.ExpressionFactory;
+import javax.el.FunctionMapper;
+import javax.el.VariableMapper;
+
+import org.springframework.binding.expression.el.DefaultELResolver;
+import org.springframework.binding.expression.el.ELContextFactory;
+import org.springframework.binding.expression.el.ELExpressionParser;
+import org.springframework.webflow.core.collection.MutableAttributeMap;
+import org.springframework.webflow.core.expression.el.RequestContextELResolver;
+import org.springframework.webflow.core.expression.el.ScopeSearchingELResolver;
+import org.springframework.webflow.execution.RequestContext;
+
+/**
+ * A JSF-specific ExpressionParser that allows beans managed by either JSF, Spring, or Web Flow referenced in
+ * expressions in the FlowDefinition.
+ * 
+ * @author Jeremy Grelle
+ */
+public class LegacyJSFELExpressionParser extends ELExpressionParser {
+
+	public LegacyJSFELExpressionParser(ExpressionFactory expressionFactory) {
+		super(expressionFactory);
+		putContextFactory(RequestContext.class, new RequestContextELContextFactory());
+		putContextFactory(MutableAttributeMap.class, new AttributeMapELContextFactory());
+	}
+
+	private static class RequestContextELContextFactory implements ELContextFactory {
+		public ELContext getELContext(Object target) {
+			List customResolvers = new ArrayList();
+			customResolvers.add(new RequestContextELResolver());
+			customResolvers.add(new ScopeSearchingELResolver());
+			customResolvers.add(new LegacyJSFBeanResolver());
+			ELResolver resolver = new DefaultELResolver(target, customResolvers);
+			return new WebFlowELContext(resolver);
+		}
+	}
+
+	private static class AttributeMapELContextFactory implements ELContextFactory {
+		public ELContext getELContext(Object target) {
+			ELResolver resolver = new DefaultELResolver(target, null);
+			return new WebFlowELContext(resolver);
+		}
+	}
+
+	private static class WebFlowELContext extends ELContext {
+
+		private ELResolver resolver;
+
+		public WebFlowELContext(ELResolver resolver) {
+			this.resolver = resolver;
+		}
+
+		public ELResolver getELResolver() {
+			return resolver;
+		}
+
+		public FunctionMapper getFunctionMapper() {
+			return null;
+		}
+
+		public VariableMapper getVariableMapper() {
+			return null;
+		}
+	}
+
+}