MACROMEDIA COLDFUSION MX 61-DEVELOPING COLDFUSION MX, Develop Manual

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244 Chapter 11: Building and Using ColdFusion Components
You can access variables in the Arguments scope using structure notation
(Arguments.variablename) or array notation (Arguments[1] or Arguments[“variablename”]).
The Arguments scope does not last between calls to CFC methods.
These variables are available to pages included by the function.
Function local variables
Variables declared with the Var keyword inside a
cffunction
tag or CFScript
function
definition are available only in the method in which they are defined, and only last from the time
the method is invoked until it returns. You cannot use the Var keyword outside of function
definitions.
All function local variables must be defined at the top of the function definition, before any other
CFML code; for example:
<cffunction ...>
<cfset Var testVariable = "this is a local variable">
...
Function code goes here
...
<cfreturn myresult>
</cffunction>
Use function local variables if you put the CFC in a persistent scope such as the Session scope,
and the function has data that must be freed when the function exits.
Local variables do not last between calls to CFC methods.
These variables are available to pages included by the method.
Other variable scopes
The CFC shares the Form, URL, Request, CGI, Cookie, Client, Session, Application, Server, and
Flash scopes with the calling page. Variables in these scopes are also available to all pages that are
included by the CFC. These variables do not have any CFC-specific behavior.
Structuring and reusing code
The following sections provide information about the techniques that ColdFusion MX provides
for structuring and reusing component code:
•
Inheritance and the Super keyword
•
Component packages
•
Persistent components
Using inheritance and the Super keyword
Component inheritance and the Super keyword are two important tools for creating structured,
object-oriented ColdFusion components.
•
Component inheritance lets you create a single, typically more general, base component and
reuse this code in multiple, typically more specific, subclasses that are derived from the base
component. Each subclass does not have to redefine the code in the base component, but can
override it if necessary.