Balu
Posts: 3
Nickname: balus
Registered: Jan, 2004
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Re: Difference between Interface and Abstract Classes
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Posted: Jan 9, 2004 2:22 AM
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Well, typically you would use an abstract class in
cases where a functionality needs to be extended. ie,
the sub class is extending something that exists but
is not complete by itself. On the other hand you would
use an interface to enforce a protocol.
One application I have seen of interface is as follows
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If you had an application that required to do database
transactions with different types of systems (ie.
Oracle, IBM Legacy systems, etc), you could use an
interface to mask the intricacies of connecting with
the various systems from the developer by providing a
common interface to all the systems, while the various
implementations of the interface could have nothing to
do with each other.
In such a case you would have no use for abstract
classes quite simply because it is not a common
functionality that you are extending.
A case for using an abstract class could be for a
banking application where CheckingAccount and
SavingAccount could derive from an abstract
BannkAccount class. Both the sub-classes would derive
some common functionality from the BankAccount class
and them add some of their own, and also BankAccount
would not be complete by itself.
s.balu
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