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Re: Re: OO Getters/Setters

by boo_radley (Parson)
on Dec 31, 2003 at 20:48 UTC ( #318007=note: print w/ replies, xml ) Need Help??


in reply to Re: OO Getters/Setters
in thread OO Getters/Setters

$self->foo(123) # chaining of mutator calls ->bar(456);
this always gave me the heebies because returning the object for success seems a little fragile. What if ->foo() fails? Is it still sensible to return the object? What happens if you have a mutator (well, a not-mutator according to hardburn) that rejects the data presented for whatever reason? If your mutator returns an error code because ->foo(123) is bad input, you wind up with, i.e., "123 is an invalid foo"->bar(456) and your code goes pear-shaped.

Sure, maybe "123 is an invalid foo" is up for argument as a sensible error code. The point is that it seems like a way to limit your object if you need to do any interesting things to communicate failure to back to your user.


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Re: Re: Re: OO Getters/Setters
by stvn (Monsignor) on Jan 01, 2004 at 01:59 UTC
    this always gave me the heebies because returning the object for success seems a little fragile.

    I couldn't agree more, and not only is returning the object fragile, but the whole idea of an accessor and a mutator (getter and setter) rolled into one subroutine seemed to be to be just a opening for interface confusion. What if i want to provide an accessor, but not a mutator. Now convention is broken, and programmer assumptions are thrown out the window. While 'getField' and 'setField' are tedious to code initially, they have a tendency to pay off in terms of maintainability and ease of understanding for others.

    What if ->foo() fails? Is it still sensible to return the object? What happens if you have a mutator (well, anot-mutator according to hardburn) that rejects the data presented for whatever reason? If your mutator returns an error code because ->foo(123) is bad input, you wind up with, i.e., "123 is an invalid foo"->bar(456) and your code goes pear-shaped.

    I would argue here though that if '->foo()' fails, then you should throw an exception, and not return an error code. In which case the method chaining doesn't matter, since you would've longjump-ed outta there already.

    -stvn

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