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Re: constructing a constant HashMap

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Tom Anderson wrote:
> On Sun, 16 Oct 2011, B1ll Gat3s wrote:
> 
>> On 16/10/2011 1:07 AM, Patricia Shanahan wrote:
>>> Roedy Green wrote:
>>>> What is your preferred way of building a HashMap when all the values
>>>> are known at compile time?
>>>
>>> If the map is a field, I often use an instance or static initializer
>>> immediately after the map's declaration:
>>>
>>> Map<String,String> myMap = new HashMap<String,String>();
>>> {
>>> myMap.put("aaa", "bbb");
>>> ...
>>> }
> 
> For static final variables (suggested by "all the values are known at 
> compile time"), i would suggest a slight variation:
> 
> static final Map<String,String> myMap;
> static {
>     Map<String,String> tmpMap = new HashMap<String,String>();
>     tmpMap.put("aaa", "bbb");
>     myMap = Collections.unmodifiableMap(tmpMap);
> }

Yes, that is indeed an improvement, given the lack of intent to modify
the map after its creation.

Patricia

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constructing a constant HashMap Roedy Green <see_website@mindprod.com.invalid> - 2011-10-15 18:14 -0700
  Re: constructing a constant HashMap Arne Vajhøj <arne@vajhoej.dk> - 2011-10-15 21:36 -0400
    Re: constructing a constant HashMap Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-10-16 16:51 +0200
  Re: constructing a constant HashMap markspace <-@.> - 2011-10-15 18:59 -0700
    Re: constructing a constant HashMap Roedy Green <see_website@mindprod.com.invalid> - 2011-10-15 19:25 -0700
  Re: constructing a constant HashMap Roedy Green <see_website@mindprod.com.invalid> - 2011-10-15 19:19 -0700
  Re: constructing a constant HashMap Patricia Shanahan <pats@acm.org> - 2011-10-16 06:07 +0100
    Re: constructing a constant HashMap B1ll Gat3s <wm.g4t3s@m1cr0s0f7.c0m> - 2011-10-16 01:29 -0400
      Re: constructing a constant HashMap Tom Anderson <twic@urchin.earth.li> - 2011-10-17 00:57 +0100
        Re: constructing a constant HashMap Patricia Shanahan <pats@acm.org> - 2011-10-17 01:02 +0100
      Re: constructing a constant HashMap Arne Vajhøj <arne@vajhoej.dk> - 2011-10-16 22:20 -0400
        Re: constructing a constant HashMap B1ll Gat3s <wm.g4t3s@m1cr0s0f7.c0m> - 2011-10-17 21:35 -0400
          Re: constructing a constant HashMap Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-10-18 09:28 -0700
            Re: constructing a constant HashMap David Lamb <dalamb@cs.queensu.ca> - 2011-10-20 12:55 -0400
    Re: constructing a constant HashMap Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-10-16 11:11 -0300
  Re: constructing a constant HashMap Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-10-16 10:39 -0700

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