Re: Enum and variable problematics

From:
jesperkn <jesperkn@gmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Mon, 11 Feb 2008 09:11:52 -0800 (PST)
Message-ID:
<7880a44f-f6bc-4c3e-b8f6-cc2c9d127644@d4g2000prg.googlegroups.com>
On 10 Feb., 21:34, Daniel Pitts
<newsgroup.spamfil...@virtualinfinity.net> wrote:

Patricia Shanahan wrote:

jesperkn wrote:
....

In psedu code the following should happend:

For each variable XX in class struct do
{
   System.out.println("name " + XX + " value " + XX.value())
}

Should print out the following:

name aa value 0
name bb value 0
name cc value 0

Is there an easier way to do this, than using enums?

Regards
Jesper


If you really need to do this, why not reflection? Use java.lang.Class
to get the Field[] for the fields you want to see. Use each Field
object's get() to obtain the value.

Patricia


Caveat, reflection in Java tends to over-complicate code.

Perhaps you should consider using an EnumMap instead of actual java fields=

..

public class DataLog {
    enum FieldName {aa, bb, cc, dd}
    List<FieldName> firstData = java.util.Arrays.asList(aa, bb, dd);=

    List<FieldName> secondDaata = java.util.Arrays.asList(aa, bb, cc=

);

    Map<FieldName, String> data =
         new EnumMap<FieldName, String>(FieldName.class);

    public void set(List<FieldName> fields, String value) {
      for (FieldName field: fields) {
         set(field, value);
      }
    }
    public void set(FieldName field, String value) {
      data.put(field, value);
    }

}

Much *much* cleaner than reflection.

--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>- Skjul te=

kst i anf=F8rselstegn -

- Vis tekst i anf=F8rselstegn -


Again, thanks for the respons. I have approximately 30-40 variables
that I get from an XML string - I know the names and the types of the
variables (since I have designed the XML string) so I have no problem
with making a class with the correct variables and types.

-- XML string --
<data>
<entry>
<name>peter</name>
<age>24years</age>
</entry>
<entry>
<name>Lea</name>
<age>31years</age>
</entry>
</data>
-- XML string --

class xmldata ()
{
  String name;
  String Age;
}

Now when I browse down my XML tree I want to set store the variables
that I "meet", in my xmldata class - programatically naturally. I like
the idea of the enumMap, but I guess that my Java is a bit rusty.
Could you please elaborate on this?

If I used getters/setters wouldn't I have to have one getter/setter
for each variable that I have?

Using reflection is definitely going accross the river to get water
since I know what variables I would expect.

Regards
Jesper

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