/*
* JBoss, Home of Professional Open Source
* Copyright 2006, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.seam.el;
import javax.el.ELContext;
import javax.el.ExpressionFactory;
import javax.el.MethodExpression;
import javax.el.ValueExpression;
import org.jboss.el.lang.EvaluationContext;
import org.jboss.seam.util.JSF;
/**
* Allows JSF action listener methods to not declare the
* totally useless ActionEvent parameter if they don't
* want to.
*
* @author Gavin King
*/
public class SeamExpressionFactory extends ExpressionFactory
{
public static final ExpressionFactory INSTANCE = new SeamExpressionFactory(EL.EXPRESSION_FACTORY);
private static final Class[] NO_CLASSES = {};
private final ExpressionFactory expressionFactory;
SeamExpressionFactory(ExpressionFactory expressionFactory)
{
this.expressionFactory = expressionFactory;
}
/**
* Wrap the base ELContext, adding Seam's FunctionMapper.
*
* Thus, any expressions with s:hasRole, s:hasPermission
* must be evaluated either via Facelets/JSP (since they
* are declared in the tld/taglib.xml or via the
* Expressions component.
*
* @param context the JSF ELContext
*/
private static EvaluationContext decorateELContext(ELContext context)
{
return new EvaluationContext( context, new SeamFunctionMapper( context.getFunctionMapper() ), context.getVariableMapper() );
}
@Override
public Object coerceToType(Object obj, Class targetType)
{
return expressionFactory.coerceToType(obj, targetType);
}
@Override
public MethodExpression createMethodExpression(ELContext elContext, String expression, Class returnType, Class[] paramTypes)
{
if ( paramTypes.length==1 && JSF.FACES_EVENT.isAssignableFrom( paramTypes[0] ) )
{
return new OptionalParameterMethodExpression(
expressionFactory.createMethodExpression( decorateELContext(elContext), expression, returnType, paramTypes ),
expressionFactory.createMethodExpression( decorateELContext(elContext), expression, returnType, NO_CLASSES )
);
}
else
{
return expressionFactory.createMethodExpression( decorateELContext(elContext), expression, returnType, paramTypes );
}
}
@Override
public ValueExpression createValueExpression(Object instance, Class expectedType)
{
return expressionFactory.createValueExpression(instance, expectedType);
}
@Override
public ValueExpression createValueExpression(ELContext elContext, String expression, Class expectedType)
{
return expressionFactory.createValueExpression( decorateELContext(elContext), expression, expectedType );
}
}