Comments on: Beware using enum constants as Map keys in performance-sensitive code. http://blog.uncommons.org/2006/12/17/beware-using-enum-constants-as-map-keys-in-performance-sensitive-code/ Rants and opinion interspersed with awe-inspiring tales of heoric software engineering endeavours. Wed, 19 Nov 2008 14:16:17 +0000 http://wordpress.org/?v=2.6.3 By: Anjan Bacchu http://blog.uncommons.org/2006/12/17/beware-using-enum-constants-as-map-keys-in-performance-sensitive-code/#comment-7 Anjan Bacchu Tue, 15 May 2007 03:38:50 +0000 http://blog.uncommons.org/?p=6#comment-7 hi there, I actually did exactly the same "mistake" but did NOT notice any big performance change. This was for a swing app -- the reason I did that was to make a LARGE if () else if () block more readable(by making it a switch/case) block. Also, almost immediately, I replaced with EnumMap -- probably that was the reason why I(nor the users/testers) we did not notice a big performance change. Unfortunately, I don't have that code with me as of now and I will have to ask my ex colleagues to investigate it. Can you specify which version of java u used ? BR, ~A hi there,

I actually did exactly the same “mistake” but did NOT notice any big performance change. This was for a swing app — the reason I did that was to make a LARGE if () else if () block more readable(by making it a switch/case) block.

Also, almost immediately, I replaced with EnumMap — probably that was the reason why I(nor the users/testers) we did not notice a big performance change.

Unfortunately, I don’t have that code with me as of now and I will have to ask my ex colleagues to investigate it.

Can you specify which version of java u used ?

BR,
~A

]]> By: Dan http://blog.uncommons.org/2006/12/17/beware-using-enum-constants-as-map-keys-in-performance-sensitive-code/#comment-5 Dan Mon, 14 May 2007 17:56:44 +0000 http://blog.uncommons.org/?p=6#comment-5 Definitely, that occurred to me after I originally posted this. The hashcode() performance is still poor, it's just not such a problem if you use EnumMap. Definitely, that occurred to me after I originally posted this. The hashcode() performance is still poor, it’s just not such a problem if you use EnumMap.

]]> By: Aviad Ben Dov http://blog.uncommons.org/2006/12/17/beware-using-enum-constants-as-map-keys-in-performance-sensitive-code/#comment-3 Aviad Ben Dov Mon, 14 May 2007 15:06:48 +0000 http://blog.uncommons.org/?p=6#comment-3 Why not use the <a href="http://java.sun.com/j2se/1.5.0/docs/api/java/util/EnumMap.html" rel="nofollow">EnumMap</a>? It promises better performance than the regular HashMap by using the ordinal value and an underlying array. Why not use the EnumMap? It promises better performance than the regular HashMap by using the ordinal value and an underlying array.

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