Matt it depends on the type, if its a primitive it returns a copy, if its an
Object it returns a reference, this is true for both ColdFusion and Java.
In coldfusion a struct is returned by reference, but a string or number
would be returned by value.
Try it and See! :)
Although that's still not what I was intending to show with my example, I
was intending to show that using variables is not private, and shouldn't be
considered private until the bug is fixed.
import java.util.*;
public class Tester {
private HashMap map = new HashMap();
private int salary = 0;
public Tester() {
map.put("1", "2");
}
public HashMap getMap() {
return map;
}
public int getSalary()
{
return salary;
}
public static void main(String args[])
{
Tester t = new Tester();
HashMap h1 = t.getMap();
h1.put("2", "3");
HashMap h2 = t.getMap();
//should output 3 if getter returned a reference
System.out.println(h2.get("2"));
int s = t.getSalary();
s = 100;
//should output 100 if getter returned a reference
System.out.println(t.getSalary());
}
}
-pete
-----Original Message-----
From: Matt Liotta [mailto:[EMAIL PROTECTED]]
Sent: Monday, September 02, 2002 7:05 PM
To: CF-Talk
Subject: RE: CFC theory
I don't know how more explicit I can get. Your getX method is returning
a reference to a private data member. Once you have a reference there is
nothing stopping you from changing the private data. Again, this is the
same as in Java.
public class Salary
{
private int salary = 100;
public int getSalary()
{
return salary;
}
}
Try it and see!
Matt Liotta
President & CEO
Montara Software, Inc.
http://www.montarasoftware.com/
V: 415-577-8070
F: 415-341-8906
P: [EMAIL PROTECTED]
> -----Original Message-----
> From: Pete Freitag [mailto:[EMAIL PROTECTED]]
> Sent: Monday, September 02, 2002 4:05 PM
> To: CF-Talk
> Subject: RE: CFC theory
>
> I don't think you saw what I was getting at, here is a very explicit
> example:
>
> <cfset foo = CreateObject("component", "Salary")>
> <cfset variables.salary = "123">
> <cfoutput>#foo.getSalary()#</cfoutput>
>
> getSalary will return 123
>
> here is an even worse example:
>
> foo.cfc:
> <cfcomponent>
> <cfset variables.x = "100">
> <cffunction name="getX">
> <cfreturn variables.x>
> </cffunction>
> <cffunction name="setX">
> <cfargument name="x">
> <cfset variables.x = arguments.x>
> </cffunction>
> </cfcomponent>
>
> test.cfm:
> <cfset foo1 = CreateObject("component", "foo")>
> <cfset foo2 = CreateObject("component", "foo")>
> <cfset foo1.setX(1)>
> <cfset foo2.setX(2)>
> <cfoutput>#foo1.getX()#</cfoutput>
>
> take a wild guess what this outputs... 2!
>
> not my idea of private.
>
> -pete
>
>
> -----Original Message-----
> From: Matt Liotta [mailto:[EMAIL PROTECTED]]
> Sent: Monday, September 02, 2002 6:38 PM
> To: CF-Talk
> Subject: RE: CFC theory
>
>
> The variable is private. However, when you use the getSalary method
you
> return a reference to the private variable. This is the same in Java
if
> you declare a variable as private and have a public "getter" that
> returns a reference to it.
>
> Matt Liotta
> President & CEO
> Montara Software, Inc.
> http://www.montarasoftware.com/
> V: 415-577-8070
> F: 415-341-8906
> P: [EMAIL PROTECTED]
>
> > -----Original Message-----
> > From: Pete Freitag [mailto:[EMAIL PROTECTED]]
> > Sent: Monday, September 02, 2002 3:40 PM
> > To: CF-Talk
> > Subject: RE: CFC theory
> >
> > > Anything placed in the variables scope is private; bug or not.
> >
> > Depends on how you look at it, sure it's private in that you can't
> access
> > cfcInstance.salary
> >
> > But you could do something like this...
> >
> > <cfset variables.salary = foo.getSalary()>
> > <cfset variables.salary = DollarFormat(variables.salary)>
> > <cfoutput>#variables.salary#</cfoutput>
> >
> > and you will change the value of the data member inside the CFC. I
> don't
> > see
> > how you can call that behavior private, because it goes against all
> the
> > reasons you would want to have private access.
> >
> > Though I agree with you if you are saying that as long as the
> developer
> > using your CFC is aware of the bug, then you can pretend that
> variables
> > scope is private, and just avoid writing code like the code above.
> >
> >
> >
>
>
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