/**
* 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();
}
}
}
}
/**
* Inserts an entity, or updates it if the primary key already exists (does not return the
* existing entity). This method may be used instead of {@link #put(Transaction,Object)} to save
* the overhead of returning 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.
* @throws DatabaseException the base class for all BDB exceptions.
*/
public void putNoReturn(Transaction txn, E entity) throws DatabaseException {
DatabaseEntry keyEntry = new DatabaseEntry();
DatabaseEntry dataEntry = new DatabaseEntry();
assignKey(entity, keyEntry);
entityBinding.objectToData(entity, dataEntry);
db.put(txn, keyEntry, dataEntry);
}
/**
* Inserts an entity and returns true, or returns false if the primary key already exists.
*
* <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.
* @return true if the entity was inserted, or false if an entity with the same primary key is
* already present.
* @throws DatabaseException the base class for all BDB exceptions.
*/
public boolean putNoOverwrite(Transaction txn, E entity) throws DatabaseException {
DatabaseEntry keyEntry = new DatabaseEntry();
DatabaseEntry dataEntry = new DatabaseEntry();
assignKey(entity, keyEntry);
entityBinding.objectToData(entity, dataEntry);
OperationStatus status = db.putNoOverwrite(txn, keyEntry, dataEntry);
return (status == OperationStatus.SUCCESS);
}
/**
* Checks whether the given data is in the current format by translating it to/from an object. If
* true is returned, data is updated.
*/
private boolean evolveNeeded(DatabaseEntry key, DatabaseEntry data, EntityBinding binding) {
Object entity = binding.entryToObject(key, data);
DatabaseEntry newData = new DatabaseEntry();
binding.objectToData(entity, newData);
if (data.equals(newData)) {
return false;
} else {
byte[] bytes = newData.getData();
int off = newData.getOffset();
int size = newData.getSize();
data.setData(bytes, off, size);
return true;
}
}
public void valueToData(V value, DatabaseEntry data) {
entityBinding.objectToData(value, data);
}