Web Development
by kevlin
Sometimes the answer that leads to cleaner code is not to change your style of evaluation, but to change what you are evaluating. There are cases when a check for null can be eliminated easily by introducing the Null Object pattern:
http://www.two-sdg.demon.co.uk/curbralan/papers/europlop/NullObject.pdf
Kevlin
by rsalcedo
Kevlin,
I was interested in reading the document you mentioned, but the link is not valid. Do you know where else it can be found?
-Ricardo
by rsalcedo
Never mind,
I found it one level up in the directory tree:
http://www.two-sdg.demon.co.uk/curbralan/papers/NullObject.pdf
Definitely. The Null pattern is a great way to eliminate NullPointerExceptions from occuring in your code. [As described in builder.com/TechRepublic e-newsletter dated Mon, 5 Nov 2001, though I'm not aware of an archive to link you to :( ].
Simple example being, when you ask your person-loading code for a person, and the ID you ask for isn't there, it returns NullPerson and not null. NullPerson is a legal person whose name is "" etc.
Hen
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