Hi,
The idea of a namespace functor is to create the object carrying the method
at usage time, optionally using the context to initialize the instance.
The functor constructor can use members/methods of the context; of course,
it is possible to use variables to expose values to that constructor but in
that case, they are accessible to the whole script which is pollution.
Think about a user (http) session or a database connection that you don't
want to expose as a variable.
>From the tests, the following code hides the 'factor' as a member of a
specialized context and use it at functor creation time.
{code}
public static class EnhancedContext extends MapContext {
int factor = 6;
}
public static class ContextualFunctor {
private final EnhancedContext context;
public ContextualFunctor(EnhancedContext theContext) {
context = theContext;
}
public int ratio(int n) {
context.factor -= 1;
return n / context.factor;
}
}
...
funcs.put("cx", ContextualFunctor.class);
JEXL.setFunctions(funcs);
JexlContext jc = new EnhancedContext();
....
e = JEXL.createExpression("cx:ratio(10) + cx:ratio(20)");
{code}
Hope this helps,
Cheers
Henrib
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