B&S deleteRecord

[Harish Yerneni]

Hi all:

Here is the spec I got

   
// Deletes a record, making the record number and associated disk
// storage available for reuse. 
// Throws SecurityException if the record is locked with a cookie
// other than lockCookie.
 
public void deleteRecord(long recNo, long lockCookie)
throws RecordNotFoundException, SecurityException

I have checked for RNFE if the record is not existing in FileManager hashmap or already marked as deleted. I have thrown security exception, when cookie is not matching with the existing cookie in the hashmap or if recno doesnt exist in the lockManager hashmap itself(question: am I OK here).

I have seen in many posts they are recommending
lockRecord() - can somebody explain me why we should use lockRecord() here. I am thinking we are deleting an already locked record. If we use lockRecord(), dont we get a new cookie value here.
deleteRecord() - fine
unlock() - fine

Here is what I have coded in my Data.class

  
public void deleteRecord(long recNo, long lockCookie)
throws RecordNotFoundException, SecurityException, DataAccessException {
//to check if the record exists at all in recordNumbers
//and also if exists not already marked for deleted.
if (fileManager.recordExists(recNo)) {
//Check if the (recNo, cookie) exists in lockedRecords
//returns false even if recNo doesnt exist in the hash map OK? 
// *DOCUMENT*
//Now the thread/client should already have the lock.
//No need to lock.
if (lockManager.isLocked(recNo, lockCookie)) {
fileManager.deleteRecord(recNo);
lockManager.unlock(recNo, lockCookie);
} else {
throw new SecurityException();
}
} else {
throw new RecordNotFoundException("RecordNotFoundException: deleteRecord()");
}
}
  

thanks,

Harish

question: Why should we lock() first, if the record is already

[mohamed sulibi]

hi;

i don't understand your question , but i think the sequence for calling client is:

 
try{
    long lockCookie = dataRef.lock(recNo);
    deleteRecord(recNo, lockCookie);
}finally{
    dataRef.unLock(recNo, lockCookie);
}

regards.
M_darim.
SCJP, SCJD in progress ...