Structure Or Record In JavaCard Framework

Question

Can anybody please tell me if there is a way to define or implement records or structures in Javacard Framework??
My IDE is eclipse and I have so many master_detail data to store in Javacard, because my card does not support DB storage(SCQL) I'm searching a way better than storring data just in arrays...
any idea about better kind of storring data on card would be so much appreciated --<--@
my data are some thing like this:
Name,Family,Age,Sex,CreditNo,....
and also:
Master : DateOfVisit, TimeOfVisit, CodeOfVisit
Detail: IndexCode, DrugName, DrugInstruction
an Example is ::
Name:Hana
Family:Bijani
Age:25
Sex:Femail
CreditNo:176.3434
Data1
DateOfVisit:2009-08-08
TimeOfVisit:14:23
CodeOfVisit:123
IndexCode:1 DrugName:Drug A DrugInstruction: someinstructA
IndexCode:2 DrugName:Drug B DrugInstruction: someinstructB
Data2
DateOfVisit:2009-08-06
TimeOfVisit:14:23
CodeOfVisit:12345
IndexCode:1 DrugName:Drug A DrugInstruction: someinstructA
IndexCode:2 DrugName:Drug B DrugInstruction: someinstructB
IndexCode:3 DrugName:Drug C DrugInstruction: someinstructC
IndexCode:4 DrugName:Drug D DrugInstruction: someinstructD
Kind Regards
Hana

Answer 1

what you want is really simple: it's a class:
public class record {
public byte[] name;
public short credit;
//no constructor means default void constructor
//use
class main {
private record[] records;
private short record_count;
//in a method, create a record
short rec_num = record_count++;
records[rec_num]=new record();
records[rec_num].credit = .....
records[rec_num].name=new byte[16];
JCSystem.arrayCopyNonAtomic( data..... , offset..... records[rec_num].name,16);
//Etc
cheat sheet:
- no string in javacards, use byte[] arrays, and encode strings to ASCII UTF8 or whatever
- no int except in rare cards, use shorts for 16 bits values, arrays of bytes to simulate ints
- no pointers in java
- struct are classes
- byte[] arrays created with new are non volatile
in general, cards are dumb. they only store raw byte arrays and the actual structure management is left to the host. This is a very robust and ubiquitous design, allowing reuse and simpification of on card code.
So in a perfect world you should'nt need a class to store records. A byte array is sufficient.
Imagine one day you want to add a new field in your record. argh!! you have to recompile/redeploy a new applet. If some millions clients already have it... fail!
However if you only store a raw record, it's just a matter or recompiling a basic java/whatever application, not a highly embedded code :)