Re: Best way to do this?

From:
Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at>
Newsgroups:
comp.lang.java.programmer
Date:
22 Jul 2010 18:38:17 GMT
Message-ID:
<slrni4h40p.sno.avl@gamma.logic.tuwien.ac.at>
harryajh <harryreg_uk@yahoo.co.uk> wrote:

         if (propName.equalsIgnoreCase("licence_number"))
        else if (propName.equalsIgnoreCase("return_requirement_id"))

One thing to avoid unnecessary waste might be to "toLowerCase()" once,
and then use plain .equals() for comparisons.

Next step would be to look up the toLowerCase()'d property name in
a HashMap, that has all 10 strings associated with a small integer,
which you then use in a switch(...){...} to get the appropriate
method called on the MyBean for each number.

The "OO" way, would be to have some interface like
 interface Storer { void store(MyBean b,String s); }
and in the HashMap you associate anonymous Storer-implementations:
   Map<String,Storer> m = new HashMap<String,Storer>();
   m.put("licence_number",new Storer() {
      public void store(MyBean b,String s) { b.setLicenceNo(s); } } );
   m.put("return_requirement_id",new Storer() {
      public void store(MyBean b,String s) { b.ret.setReturnReqId(s); } } );
   // ... ditto for the further 8 mappings

   MyBean b = new MyBean();

Then, inside the loop:
   m.get(rs.getString(2).toLowerCase()).store(b,rs.getString(3));

Well, actually you may want to break this up into separate statements
storing intermediate results in local variables and do null-checks
where appropriate.

For best encapsulation, you could add a method to MyBean, that takes
the Property's name and new value, and does the HashMap-lookup and
invocation of the obtained Storer. The HashMap itself would also be
maintained by MyBean and created and populated in the static initializer,
or lazily on first use.

I do not claim, that any of these would actually make your whole program
faster, but I dislike those if-chains, anyway, so even if your program
doesn't end up faster, I think those alternatives would still be worth
considering.

PS: "myBean" was a bad class-name and "GetString" is not a method of
   ResultSet, so I changed them.

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