struts-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Andrew Hill" <andrew.david.h...@gridnode.com>
Subject RE: abstract class
Date Wed, 04 Dec 2002 12:44:18 GMT
<snip>
So your sub
class (a derivation of your base class) needs to call into its super class,
it is done with a super() call. The super() call is (and must be) the first
statement in the subclass's overriding method.
</snip>

Thats just for constructors. Ive got a few places where a subclass overrides
a normal method in which it checks something and if a certain condition is
met it does some special behaviour, but if not makes a call to the
superclass implementation of the method in order to proceed as normal. Thats
using the syntax super.doSomething(), while super() is what you use if your
in a constructor - in that case it must be the first statement, but for
normal methods it can be called anytime.

-----Original Message-----
From: Brian Hickey [mailto:bhickey@r-effects.com]
Sent: Wednesday, December 04, 2002 20:26
To: Struts Users Mailing List
Subject: Re: abstract class


Mohan,

Two different behaviors is what you wish then you need to derive from a
concrete base class. Abstract classes are more likely to provide conformance
to an architecture or signature template.

In Struts, folks usually inherit from the Action class to create certain
behaviors. If you need to super() to a base class, you are correct, it
cannot be an abstract class. I would suggest that it shouldn't be in most
any case, but I don't know your architecture.

It is also early and I am not sure of your terminology. A base class is a
super class (standard inheritance diagrams display that way) and subsequent
derivations are known as subclasses. When you want to use the code in a
super class from your sub class, you user super() to call it. So your sub
class (a derivation of your base class) needs to call into its super class,
it is done with a super() call. The super() call is (and must be) the first
statement in the subclass's overriding method.

All of this seems too easy, so I am sure I have completely missed the point.

Brian


----- Original Message -----
From: "Mohan Radhakrishnan" <MohanR@hclcomnet.co.in>
To: "Struts Users Mailing List" <struts-user@jakarta.apache.org>
Sent: Wednesday, December 04, 2002 5:47 AM
Subject: abstract class


> Hi,
>
>    If an action has two different behaviours then it is advised to use an
> abstract method in the base class that the sub-action can override.
>
>    Our base action's perform method has to pass control to a sub action's
> method for the varying behavior. But if we use an abstract method then the
> action cannot be instantiated.
>
>  How is this usually done?
> Thanks,
> mohan
>
> --
> To unsubscribe, e-mail:
<mailto:struts-user-unsubscribe@jakarta.apache.org>
> For additional commands, e-mail:
<mailto:struts-user-help@jakarta.apache.org>
>
>


--
To unsubscribe, e-mail:
<mailto:struts-user-unsubscribe@jakarta.apache.org>
For additional commands, e-mail:
<mailto:struts-user-help@jakarta.apache.org>


--
To unsubscribe, e-mail:   <mailto:struts-user-unsubscribe@jakarta.apache.org>
For additional commands, e-mail: <mailto:struts-user-help@jakarta.apache.org>


Mime
View raw message