FileDocCategorySizeDatePackage
ParametersFile.javaAPI DocJava Card3171Wed Mar 22 21:07:24 GMT 2006package com.sun.javacard.samples.JavaPurseCrypto

ParametersFile

public class ParametersFile extends Object
This is the class for all linear variable-length record files, and the base class for linear variable-fixed and cyclic record files.

Fields Summary
Record[]
records
byte
numRecords
Constructors Summary
public ParametersFile(byte maxNumRecords)
Constructor.

param
maxNumRecords the maximum number of records in this file

    records = new Record[maxNumRecords];
	numRecords = 0;
Methods Summary
public voidaddRecord(byte[] record)
Add (append) a new record to the file. Note that the record reference is stored in the file object. A copy of the record byte array is not made.

param
record the record byte array
exception
ISOException if the file is full.
  • ISOException.reason = ISO7816.SW_FILE_FULL 

     if ( records.length == numRecords)
       ISOException.throwIt(ISO7816.SW_FILE_FULL);
     records[numRecords++] = new Record(record);
public bytefindRecord(byte firstByte)
Find the record.

param
firstByte if non-0, the record's first byte must match this value; if 0, any value of the record's first byte matches.
return
the record number, or 0 if the record is not found


     // empty file
     if (numRecords == 0)
       return 0;

     byte eRecNum = numRecords; // existing record number
	 byte currentRecNumber = 1;
     byte thisRec[];

     while (true) {

       thisRec = getRecord(currentRecNumber);

       if ( firstByte == 0) {
          return currentRecNumber;
       }

       if ( thisRec[0] == firstByte) {
           return currentRecNumber;
       }

      if ( currentRecNumber == eRecNum )
        return 0;
      currentRecNumber++;
    }
public bytegetNumRecords()
Get the actual number of records in this file.

return
numRecords

    return numRecords;
public byte[]getRecord(byte recordNum)
Get the record byte array for the specified record number. This is a reference to the actual file data, not a copy of the file data. Records are in the order that they were added to the file. Record number is in the range from 1 to the number of records in the file

param
recordNum the index (first record = 1) of the record.
return
record or null if the record is not found


     // current record only has meaning in the context of file system
     // file system will translate 0 to the currentRecord number in
     // its methods
     // but you can not pass in 0 to getRecord directly
     if ( (recordNum <= 0) || ( recordNum > numRecords) )
       return null;

     return records[recordNum-1].record;