function-mapper

== The function-mapper Directive ==

<source lang="xml" >
 <?function-mapper class="..." 
   [arg0="..."] [arg1="..."] [arg2="..."] [arg3="..."]?>
</source>

Specifies the function mapper that will be used by the EL expressions to resolve unknown function. The specified class must implement the <tt>org.zkoss.xel.FunctionMapper</tt> interface.

You can specify multiple variable resolvers with multiple <tt>function-mapper</tt> directives. The later declared one has higher priority.

Notice that the <tt>function-mapper</tt> directives are evaluated before the <tt>init</tt> directives.

=== class ===

<source lang="xml" >
[Optional]
</source>

A class name that must implement the <tt>org.zkoss.xel.FunctionMapper</tt> interface. Unlike the <tt>init</tt> directive, the class name cannot be the class that is defined in zscript codes.

=== arg0, arg1... ===

<source lang="xml" >
[Optional]
</source>

You could specify any number of arguments. If not specified, the default constructor is assumed. If specified, it will look for the constructor with the signature in the following order:

# Foo(Map args)
# Foo(Object[] args)
# Foo()

If the first signature is found, the arguments with the name and value are passed to the constructor as an instance of <tt>Map</tt>. If the second signature is found, the values of arguments are passed to the constructor as an array of objects.

Prior to ZK 3.6.2, only the second signature is checked if one or more argument is specified, and it assumes <tt>arg0</tt> as the first argument, <tt>arg1</tt> as the second, and so on.

On the hand, you, with ZK 3.6.2 or later, can use any readable name for arguments as follows.

<source lang="xml">
<?function-mapper class="foo.Foo" whatever="anything"?>
</source>