Weird RecordStore behavior when RecordStoreFullException occurs
- by Michael P
Hello everyone!
I'm developing a small J2ME application that displays bus stops timetables - they are stored as records in MIDP RecordStores.
Sometimes records can not fit a single RecordStore, especially on record update - using setRecord method - a RecordStoreFullException occurs. I catch the exception, and try to write the record to a new RecordStore along with deleting the previous one in the old RecordStore.
Everything works fine except of deleting record from RecordStore where the RecordStoreFullException occurs. If I make an attempt to delete record that could not be updated, another Exception of type InvalidRecordIDException is thrown. This is weird and undocumented in MIDP javadoc. I have tested it on Sun WTK 2.5.2, MicroEdition SDK 3.0 and Nokia Series 40 SDK. Furthermore I created a code that reproduces this strange behaviour:
RecordStore rms = null;
int id = 0;
try {
rms = RecordStore.openRecordStore("Test", true);
byte[] raw = new byte[192*10024]; //Big enough to cause RecordStoreFullException
id = rms.addRecord(raw, 0, 160);
rms.setRecord(id, raw, 0, raw.length);
} catch (Exception e) {
try {
int count = rms.getNumRecords();
RecordEnumeration en = rms.enumerateRecords(null, null, true);
count = en.numRecords();
while(en.hasNextElement()){
System.out.println("NextID: "+en.nextRecordId());
}
rms.deleteRecord(id); //this won't work!
rms.setRecord(id, new byte[5], 0, 5); //this won't work too!
} catch (Exception ex) {
ex.printStackTrace();
}
}
I added extra enumeration code to produce other weird behavior - when RecordStoreFullException occurs, count variable will be set to 1 (if RMS was empty) by both methods - getNumRecords and numRecords. System.out.println will produce NextID: 0! It is not acceptable because record ID can not be 0!
Could someone explain this strange behavior?
Sorry for my bad English.
