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From: Lew <noone@lewscanon.com>
Newsgroups: comp.lang.java.help
Subject: Re: Is it sign of bad Object Oriented programming?
Date: Sun, 24 Apr 2011 17:26:20 -0400
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Patricia Shanahan wrote:
> Lew wrote:
>> Eric Sosman wrote:
>>> Merciadri Luca wrote:

>>>> Let us consider a class Class and an object myObj of type Class. Let
>>>> there be a method myMeth defined in the Class class.
>>>>
>>>> Are there some cases where typing e.g. [sic]
>>>> ==
>>>>   myObj.myMeth(myObj)
>>>> ==
>>>> is not considered as `bad style?' That is, are there, more generally,
>>>> some situations where passing an instanciated object to a method of
>>>> this object is a good way of achieving something?

>>> boolean arrayHasEqualThing(Thing[] array, Thing thing) {
>>>   for (Thing t : array) {
>>>     if (t.equals(thing)) // Look here!
>>>       return true;
>>>   }
>>>   return false;
>>> }

>> This differs from the problem statement, which has the argument
>> reference the same instance as that through which the (instance) method
>> is called. The method that you show here is a candidate for 'static'
>> scope as it does not depend on the state of 'this'. In particular, there
>> is no guarantee in this proposal that 't' or 'thing' point to the 'this'
>> instance, nor to the same instance as each other.

> Consider an arithmetic type Widget, like BigInteger, with a multiply
> method that returns the Widget representing the product of this and a
> Widget argument.
>
> Now write Widget's square method:
>
> public Widget square() {
>   return multiply(this);
> }
>
> Is that what is being discussed?

Of course, the OP will have to clarify this, but the example given was:

   myObj.myMeth(myObj)

This represents a client, not 'this', calling a method that takes the 
reference itself as an argument.  Stefan Ram gave a motivating example:

   System.out.println( System.out );

Your example doesn't fit the proffered pattern.

-- 
Lew
Honi soit qui mal y pense.
http://upload.wikimedia.org/wikipedia/commons/c/cf/Friz.jpg