Hi "JS Portal Support",
sorry about the last incomplete post - my mail client was so eager to send that
mail away - I could not stop him from doing so... ;o)
Last year I did something you intend. I was heavily disturbed about how
ignorant the JSF standard is about this basic programming requirement to use
constants instead of hard-coded values in your JSPs.
I put all my application wide constants in a single "Constants" class. Then I
used a ServletContextListener to put all the fields via introspection in a Map
in the application scope (not as a backing bean, but as ServletContext
attribute) using the key "Constants".
Constants class:
----------------
public final class Constants {
// ID for reference from the ServletContext:
public static final String ID = "Constants";
// other constants follow...
public static final String TAB_DETAILS = "tabDetails";
...
// "cache" holding all public fields by it's field name:
private static Map nameToValueMap = createNameToValueMap();
/**
* Puts all public static fields into the resulting Map.
* Uses the name of the field as key to reference it's in the Map.
*
* @return a Map of field names to field values of
* all public static fields of this class
*/
private static Map createNameToValueMap() {
Map result = new HashMap();
Field[] publicFields = Constants.class.getFields();
for (int i = 0; i < publicFields.length; i++) {
Field field = publicFields[i];
String name = field.getName();
try {
result.put(name, field.get(null));
} catch (Exception e) {
System.err.println("Initialization of Constants
class failed!");
e.printStackTrace(System.err);
}
}
return result;
}
public static Map getNameToValueMap() {
return nameToValueMap;
}
}
Listener class:
---------------
...
public void contextInitialized(ServletContextEvent event) {
ServletContext sc = event.getServletContext();
sc.setAttribute(Constants.ID, Constants.getNameToValueMap());
}
...
This way I could access all my constants in the JSPs via JSF expression:
<c:if test="${globalView.linieTab eq Constants.TAB_DETAILS}">
Since the expression language allows you to reference mapped values via
Map['key'] or Map.key, I could use the "dot" syntax to mimic a normal static
access to the Constants classes fields.
I hope this helps you achieve your goal of reusable constant values throughout
your application.
Ciao,
René
----- Original Message -----
From: JS Portal Support
[mailto:[EMAIL PROTECTED]
To: [email protected]
Sent: Mon, 25 Sep
2006 13:20:13 +0200
Subject: How to reference a static value in JSF
> Hi,
>
> Just started to implement Shale and JSF. As I've always worked more with
> scriptlets and Servlets I can't seem to figure out how to reference a public
> static value from one of my classes in my JSP's. I've always used:
>
> <input type="hidden" name="a"
> value="<%=com.jsportal.projectportal.web.webActions.login%>"/>
>
> Now I try to achieve this with the following:
>
> <h:inputHidden id="a"
> value="${com.jsportal.projectportal.web.webActions.login}"/>
>
> I understand this doesn't work as it will try to call
> com.getJsportal()....etc. But how do I do it, as the <%=%> is not allowed in
> these taglib tags?
>
> Thanks,
> Joost
>
>
