Re: How to prevent code repetition with enums?

From:
Piotr Kobzda <pikob@gazeta.pl>
Newsgroups:
comp.lang.java.programmer
Date:
Fri, 17 Nov 2006 15:42:56 +0100
Message-ID:
<ejkhsc$68p$1@inews.gazeta.pl>
Chris Uppal wrote:

daniel_nordlund_1982@hotmail.com wrote:

Hello. I was wondering if there is a better way to write the below
code. I have several enums, where each enum is for an option type and
each option has a short 1-3 letter string used when I need to identify
the option from a string. The code for each option type is identical
and I'd prefer to not repeat it over and over again.


As far as I know there is no way to remove the repetition. So, if it bothers
you particularly (and it would bother me ;-) I suggest that you generate the
enum classes automatically.


Yes. That's the option.

But a little improvement is also possible here with a single
implementation of the lookup logic, like in the following example:

public class Options {

     public interface Option {
         String getOptionString();
     }

     public static enum YesNoOption implements Option {
         YES("yes"), NO("no");
         private final String str;
         private YesNoOption(String str) { this.str = str; }
         public String getOptionString() { return str; }
         public static YesNoOption getOption(String str) {
             return forString(YesNoOption.class, str);
         }
     }

     // ... other options ...

     public static <T extends Enum<T> & Option> T forString(
             Class<T> optionType, String str) {
         for(T o : optionType.getEnumConstants())
             if(o.getOptionString().equals(str))
                return o;
         return null;
     }

}

piotr

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