why inject the static part in the EL-expression just write the custom resolver and have him check whether the property name resolves to a static-classmember and return it... hth Alexander
________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Craig McClanahan Sent: Wednesday, February 07, 2007 10:52 PM To: MyFaces Discussion Subject: Re: AW: Accessing constants in EL expressions On 2/7/07, Simon Kitching <[EMAIL PROTECTED]> wrote: The EL language is defined to provide access to Java Bean Properties, and only Java Bean Properties. Static fields are not regarded as Java Bean Properties by the java.beans.Introspector class, hence are not accessable. Yes, it sucks but this is the JSF spec. Well, actually the JSF spec says: <quote> The syntax of a value binding expression is identical to the syntax of an expression language expression defined in the JavaServer Pages Specification (version 2.0), sections 2.3 through 2.9, with the following exceptions ... </quote> where the exceptions are not relevant in this case. And the JSP spec says that a.b and a[b] are: <quote> used to access maps, lists, arrays of objects and properties of a Java- Beans object </quote> See: http://java.sun.com/javaee/javaserverfaces/download.html http://java.sun.com/products/jsp/reference/api/index.html http://java.sun.com/products/jsp/syntax/2.0/syntaxref207.html#1010522 <http://java.sun.com/products/jsp/syntax/2.0/syntaxref207.html#1010522> Therefore to get access to static constants working, what is needed is to ensure that the data you want *is* a Java Bean Property (read-only in the case of constants). The ways to do this are: 1. add a getter method, getCONSTANT 2. add a getter method for a Map which provides access to the constants 3. play clever tricks with a BeanInfo class. If you want to solve it once and for all, consider implementing a custom PropertyResolver to do the dirty work. The goal would be to translate something like #{foo.static.BAR} into the value of the static constant BAR on whatever class foo resolves to. The getValue() method for this custom PropertyResolver would need to do something like this: * If the property name is "static", create some sort of proxy object that is configured with the class of the base object and return that. * Else if the base object is an instanceof the proxy class described above, treat the property name as the name of a static constant, use reflection to retrieve the value, and return that. * Else delegate to the previous PropertyResolver instance. Being able to customize the evaluation of expressions is very powerful. Also, while the concept above refers to PropertyResolver and is therefore relevant for JSF 1.1, the same concept works with ELResolver in JSF 1.2 (with the added benefit that your custom resolvers are used for JSP ${...} expressions as well as JSF #{...} expressions). Craig
