Thanks a lot , i got the points.


On Fri, Dec 18, 2009 at 1:57 AM, Nic Fox <[email protected]> wrote:

> In the first case, being able to change the implementation without
> affecting the caller of the interface is one of the advantages of
> encapsulation. The example in the PDF mentions an interface method with the
> signature:
>
>
> checkIsGreater(Object x, Object y)
>
>
> Any object/method that calls this method is the caller. So for example if
> the main method called:
>
> SomeComparisonObject.checkIsGreater(ObjectA, ObjectB);
>
>
> then the main method is the caller. The main method is not concerned with
> how checkIsGreater works, it only matters that the return type and parameter
> list remains the same. If for some reason the code inside checkIsGreater
> needs to be changed, then doing so will not affect other parts of the
> program so any changes should be confined to that method only.
>
> Following on from the above, your second question regarding compile time
> checking should be a bit easier to figure out. Because in this case the
> compiler is only concerned with checking method calls that are compatible
> with the method signatures. In this case the compiler checks against the
> interface (which is a form of abstraction) rather than against the
> implementation (which is not abstract i.e. it is 'concrete').
>
> On 18/12/2009, at 1:01 AM, nn roh wrote:
>
> Hi ,
>
> I couldn't understand  the highlighted text, it is one of reasons why we
> use interface..
>
>
> To reveal an object's programming interface
> (functionality of the object) without revealing its
> implementation
> – This is the concept of encapsulation
> – The implementation can change without affecting
> the caller of the interface                      what he mean by the
> caller of the interface?
>
>
> – The caller does not need the implementation at the
> compile time ??
>
> ● It needs only the interface at the compile time ?
>
> your help& sharing much appreciated ,
>
> Thanks
> Nada
>
> On Thu, Dec 17, 2009 at 3:23 PM, NISHANT BULCHANDANI <
> [email protected]> wrote:
>
>> hello,
>> i don't know whether thios is the right place to ask.sry if m wrong.well,
>> i thought of learning java<start> and i have it this sem... so if anyone
>> could guide me how to use this resource and about SCJP (its advantages...hw
>> to start nd all)....
>> thanks
>>
>>
>>
>
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