make sense....I just came up with this similar answer on my way
home...Thanks.
在 2012年7月18日星期三UTC+8下午6时56分42秒，dennis写道：
>
> I think this cache is just the same with String.intern method in java,it
> just want to reduce the cost (memory & cpu) of producing keywords
> frequently especial when using them with map structure.
>
> 2012/7/18 jaime <xiejianm...@gmail.com>
>
>> I doubt because keyword will use its internal Symbol object to compare
>> with each other (or other objects), it means it's Symbol's interned
>> strings(ns & name) make the comparison fast but not this caching stuff. I
>> found a "find()" method in source code but not sure if the cache is
>> relevant to this method.....
>>
>> 在 2012年7月18日星期三UTC+8下午4时52分25秒，dennis写道：
>>
>>> Compare keywords can be very fast.
>>> 在 2012-7-18 PM4:51，"jaime" <xiejianm...@gmail.com>写道：
>>>
>>>> Hello,
>>>>
>>>> When I read the source code keyword, say, Keyword.java (V1.3), I found
>>>> that when we "intern" a keyword, (if I understand it correctly) it uses
>>>> a cache for keywords:
>>>> ==============================**===============
>>>> public static Keyword intern(Symbol sym) {
>>>> if (sym.meta() != null)
>>>> sym = (Symbol) sym.withMeta(null);
>>>> *Util.clearCache(rq, table);*
>>>> Keyword k = new Keyword(sym);
>>>> Reference<Keyword> existingRef = table.putIfAbsent(sym,
>>>> new WeakReference<Keyword>(k, rq));
>>>> if (existingRef == null)
>>>> return k;
>>>> Keyword existingk = existingRef.get();
>>>> if (existingk != null)
>>>> return existingk;
>>>> // entry died in the interim, do over
>>>> table.remove(sym, existingRef);
>>>> return intern(sym);
>>>> }
>>>> ==============================**================
>>>>
>>>> well, I just don't understand why we need caching for keywords. Anyone
>>>> could give me a hint?
>>>>
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>>>
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>
>
>
> --
> 庄晓丹
> Email: killme2...@gmail.com xzhu...@avos.com
> Site: http://fnil.net
> Twitter: @killme2008
>
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