Variables should automatically be available to their child contexts so I
don't think you need to create your own JellyContext for that.
Also the push/pop features can be used by just creating and using child
context - its rather like using a local block in Java. There's also the
<j:scope> tag which creates a child variable scope, essentially making any
variables set inside the <j:scope> tag
One question; where will you be using these typesafe getters and setters you
want? Will it be inside a Jelly Tag implementation? If so, you could put
these typesafe methods in an AbstractTag...
public abstract class MyAbstractTag extends TagSupport {
public Number getFoo() {
return (Number) context.getVariable("foo");
}
... etc.
James
-------
http://radio.weblogs.com/0112098/
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, December 05, 2002 2:40 PM
Subject: RE: [jelly] Subclassing JellyContext
James, thanks for the pointer re createChildContext().
I am not clear what the scoping refactoring you refer to means exactly, even
after reading the link you sent ;-) But never mind. My scoping
requirements are to be able to have a variable value visible only to its
children. Maybe this is supported already, but I have gone ahead and
written this:
protected void pushVariable(String variableName, Object value) {
if ( context.getVariable(variableName) != null ) {
oldVariableValues.put(variableName,context.getVariable(variableName));
} else {
newVariableNames.add(variableName);
}
log.debug("Setting variable " + variableName + " to value " +
value);
context.setVariable(variableName,value);
}
followed by
protected void popVariables() {
log.debug("Starting to pop variables");
for(Iterator i=newVariableNames.iterator();i.hasNext();) {
final String variableName = (String)i.next();
log.debug("Removing variable named " + variableName);
context.removeVariable(variableName);
}
for(Iterator i=oldVariableValues.keySet().iterator();i.hasNext();) {
final String variableName = (String) i.next();
log.debug("Resetting value for variable named " + variableName);
context.setVariable(variableName,oldVariableValues.get(variableName));
}
}
And these two methods are on an AbstractTag. I _would_ prefer to have the
methods on a context though.
But the real reason I want to subclass is to allow myself write typesafe and
intuitive variable setters and getters for variables that have meaning to my
application.
So instead of
context.setVariable(VariableNames.APPLICATION_MODE,"fast")
I can do
((MyContext)context).setApplicationMode("fast")
and then
String applicationMode = ((MyContext)context).getApplicationMode()
Better than having to remember a bunch of names of variables and what type
they are.
> -----Original Message-----
> From: ext James Strachan [mailto:[EMAIL PROTECTED]]
> Sent: 05. December 2002 16:22
> To: Jakarta Commons Developers List
> Subject: Re: [jelly] Subclassing JellyContext
>
>
> There's a factory method, createChildContext() which you can
> override to
> create your own context...
>
> public class MyContext extends JellyContext {
>
> public MyContext(JellyContext parent) {
> super(parent);
> }
>
> protected JellyContext createChildContext() {
> return new MyContext(this);
> }
> }
>
> Note that soon we'll be refactoring the variable scope logic
> out of the
> JellyContext so that you could just provide your own variable Scope
> implementation to change how variables behave. Thats
> typically the usual
> reason folks need their own JellyContext implementation
>
> There's more details of this here...
>
> http://jira.werken.com/secure/ViewIssue.jspa?key=JELLY-1
>
> James
> -------
> http://radio.weblogs.com/0112098/
> ----- Original Message -----
> From: <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Thursday, December 05, 2002 1:13 PM
> Subject: [jelly] Subclassing JellyContext
>
>
> Hi,
>
> Is there any way I can override the creation of JellyContext
> instances so I
> can put in my own subclass?
>
> Thanks,
> Mike.
>
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