me.jaksa

Class LongTransactions

java.lang.Object

me.jaksa.LongTransactions

public class LongTransactions
extends Object

Provides utility functions for lightweight transaction management. Full ACID transaction semantics are NOT provided. The methods of this class allow multiple transactional operations to be performed atomically. Unlike the methods \ from Transactions, the methods here don't require the operations to be chained together but can be interleaved with non-transactional operations. As with the methods from Transactions the atomicity provided here is of the weak type. The methods in this class may be used in three different ways. The simplest form is using the longTransaction(RunnableWithException) to wrap individual transactional operations in a transaction. The operations themselves must be defined using the transactionally(FunctionalTransaction) method. The main body of each operation will be performed immediately, but the commit and rollback parts will be performed only when the long transaction is comitted/rolled back. Another possibility is to manually control the transaction using beginTx(), commitTx() and rollbackTx(). These methods make it easier to access variables defined during the transaction after the transaction finishes. Notice that these methods are bound to the current thread, so if you use multithreading (e.g. parallel streams) within the transaction, it will not work. Transactional operations are again defined using the transactionally(FunctionalTransaction) method. The third way to control a transaction is to use the LongTransaction object returned by beginTx(). This object has the LongTransaction.commit() and LongTransaction.rollback() methods. The transactional operations are added using the LongTransaction.transactionally(FunctionalTransaction) method. This way of explicitly referencing the transaction allows multithreaded code to be run within a transaction. Notice that LongTransaction implements AutoCloseable which means that the transaction will be committed unless a rollback has been called before.

See Also:

Transactions

Constructor Summary

Constructors

Constructor and Description
LongTransactions()

Method Summary

Modifier and Type	Method and Description
static me.jaksa.LongTransaction	beginTx() Starts a LongTransaction and binds it to the current thread.
static void	commitTx() Commits the LongTransaction bound to the current thread.
static void	longTransaction(RunnableWithException r) Defines the transaction boundaries.
static void	rollbackTx() Rolls back the LongTransaction bound to the current thread.
static <T> T	transactionally(FunctionalTransaction<T> operation) Adds a transactional operation the the transaction bound to the current thread.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LongTransactions

public LongTransactions()

Method Detail

longTransaction

public static void longTransaction(RunnableWithException r)

Defines the transaction boundaries. Before executing the supplied runnable, a transaction will be started and will be comitted in the end, unless an exception is thrown. If an exception is thrown by the runnable, the transaction will be rolled back. Individual operations are defined using the method transactionally(FunctionalTransaction).

Parameters:

r - the runnable to execute in a transaction

beginTx

public static me.jaksa.LongTransaction beginTx()

Starts a LongTransaction and binds it to the current thread.

Returns:

a new LongTransaction

commitTx

public static void commitTx()

Commits the LongTransaction bound to the current thread. All transactional operations defined with transactionally(FunctionalTransaction) will be committed.

rollbackTx

public static void rollbackTx()

Rolls back the LongTransaction bound to the current thread. All transactional operations defined with transactionally(FunctionalTransaction) will be rolled back.

transactionally

public static <T> T transactionally(FunctionalTransaction<T> operation)

Adds a transactional operation the the transaction bound to the current thread. The body of the operation and the verification will be performed immediately, but the commit or rollback parts will be performed only when the LongTransaction is committed/rolled back.

Type Parameters:

T -

Parameters:

operation -

Returns: