/**
* Creates an instance of this class.
*
* @param env the Berkeley DB environment
* @param timeout the number of milliseconds the transaction should be allowed to run
* @throws IllegalArgumentException if timeout is less than {@code 1}
* @throws DbDatabaseException if an unexpected database problem occurs
*/
BdbTransaction(Environment env, long timeout) {
if (timeout <= 0) {
throw new IllegalArgumentException("Timeout must be greater than 0");
}
try {
txn = env.beginTransaction(null, null);
/* Avoid overflow -- BDB treats 0 as unlimited */
long timeoutMicros = (timeout < (Long.MAX_VALUE / 1000)) ? 1000 * timeout : 0;
txn.setTxnTimeout(timeoutMicros);
} catch (DatabaseException e) {
throw BdbEnvironment.convertException(e, false);
}
}
/**
* Inserts an entity and returns null, or updates it if the primary key already exists and returns
* the existing entity.
*
* <p>If a {@link PrimaryKey#sequence} is used and the primary key field of the given entity is
* null or zero, this method will assign the next value from the sequence to the primary key field
* of the given entity.
*
* @param txn the transaction used to protect this operation, null to use auto-commit, or null if
* the store is non-transactional.
* @param entity the entity to be inserted or updated.
* @return the existing entity that was updated, or null if the entity was inserted.
* @throws DatabaseException the base class for all BDB exceptions.
*/
public E put(Transaction txn, E entity) throws DatabaseException {
DatabaseEntry keyEntry = new DatabaseEntry();
DatabaseEntry dataEntry = new DatabaseEntry();
assignKey(entity, keyEntry);
boolean autoCommit = false;
Environment env = db.getEnvironment();
if (transactional && txn == null && DbCompat.getThreadTransaction(env) == null) {
txn = env.beginTransaction(null, getAutoCommitTransactionConfig());
autoCommit = true;
}
CursorConfig cursorConfig = null;
if (concurrentDB) {
cursorConfig = new CursorConfig();
DbCompat.setWriteCursor(cursorConfig, true);
}
boolean failed = true;
Cursor cursor = db.openCursor(txn, cursorConfig);
LockMode lockMode = locking ? LockMode.RMW : null;
try {
while (true) {
OperationStatus status = cursor.getSearchKey(keyEntry, dataEntry, lockMode);
if (status == OperationStatus.SUCCESS) {
E existing = entityBinding.entryToObject(keyEntry, dataEntry);
entityBinding.objectToData(entity, dataEntry);
cursor.put(keyEntry, dataEntry);
failed = false;
return existing;
} else {
entityBinding.objectToData(entity, dataEntry);
status = cursor.putNoOverwrite(keyEntry, dataEntry);
if (status != OperationStatus.KEYEXIST) {
failed = false;
return null;
}
}
}
} finally {
cursor.close();
if (autoCommit) {
if (failed) {
txn.abort();
} else {
txn.commit();
}
}
}
}
private void run() throws DatabaseException {
Random rand = new Random();
/*
* Create a set of events. Each insertion is a separate, auto-commit
* transaction.
*/
System.out.println("-> Inserting 4 events");
eventByTime.put(new Event(makeDate(1), 100, "Company_A"));
eventByTime.put(new Event(makeDate(2), 2, "Company_B"));
eventByTime.put(new Event(makeDate(3), 20, "Company_C"));
eventByTime.put(new Event(makeDate(4), 40, "CompanyD"));
/* Load a whole set of events transactionally. */
Transaction txn = env.beginTransaction(null, null);
int maxPrice = 50;
System.out.println("-> Inserting some randomly generated events");
for (int i = 0; i < 25; i++) {
Event e = new Event(makeDate(rand.nextInt(365)), rand.nextInt(maxPrice), "Company_X");
if ((i % 2) == 0) {
e.addRep("Bob");
e.addRep("Nikunj");
} else {
e.addRep("Yongmin");
}
eventByTime.put(e);
}
txn.commitWriteNoSync();
/*
* Windows of events - display the events between June 1 and Aug 31
*/
System.out.println("\n-> Display the events between June 1 and Aug 31");
Date startDate = makeDate(Calendar.JUNE, 1);
Date endDate = makeDate(Calendar.AUGUST, 31);
EntityCursor<Event> eventWindow = eventByTime.entities(startDate, true, endDate, true);
printEvents(eventWindow);
/*
* Display all events, ordered by a secondary index on price.
*/
System.out.println("\n-> Display all events, ordered by price");
EntityCursor<Event> byPriceEvents = eventByPrice.entities();
printEvents(byPriceEvents);
}