org.apache.tinkerpop.gremlin.structure

Interface Transaction

All Superinterfaces:

AutoCloseable

public interface Transaction
extends AutoCloseable

A set of methods that allow for control of transactional behavior of a Graph instance. Providers may consider using AbstractTransaction as a base implementation that provides default features for most of these methods.

It is expected that this interface be implemented by providers in a ThreadLocal fashion. In other words transactions are bound to the current thread, which means that any graph operation executed by the thread occurs in the context of that transaction and that there may only be one thread executing in a single transaction.

It is important to realize that this class is not a "transaction object". It is a class that holds transaction related methods thus hiding them from the Graph interface. This object is not meant to be passed around as a transactional context.

Author:

Marko A. Rodriguez (http://markorodriguez.com), Stephen Mallette (http://stephen.genoprime.com), TinkerPop Community (http://tinkerpop.apache.org)

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Transaction.CLOSE_BEHAVIOR Behaviors to supply to the onClose(Consumer).
static class	Transaction.Exceptions
static class	Transaction.READ_WRITE_BEHAVIOR Behaviors to supply to the onReadWrite(Consumer).
static class	Transaction.Status A status provided to transaction listeners to inform whether a transaction was successfully committed or rolled back.

Method Summary

Modifier and Type	Method and Description
void	addTransactionListener(Consumer<Transaction.Status> listener) Adds a listener that is called back with a status when a commit or rollback is successful.
void	clearTransactionListeners() Removes all transaction listeners.
void	close() Closes the transaction where the default close behavior defined by {onClose(Consumer)} will be executed.
void	commit() Commits a transaction.
<G extends Graph> G	createThreadedTx() Creates a transaction that can be executed across multiple threads.
boolean	isOpen() Determines if a transaction is currently open.
Transaction	onClose(Consumer<Transaction> consumer) Describes what happens to a transaction on a call to Graph.close().
Transaction	onReadWrite(Consumer<Transaction> consumer) Describes how a transaction is started when a read or a write occurs.
void	open() Opens a transaction.
void	readWrite() An internal function that signals a read or a write has occurred - not meant to be called directly by end users.
void	removeTransactionListener(Consumer<Transaction.Status> listener) Removes a transaction listener.
void	rollback() Rolls back a transaction.

Method Detail

open

void open()

Opens a transaction.

commit

void commit()

Commits a transaction. This method may optionally throw TransactionException on error. Providers should consider wrapping their transaction exceptions in this TinkerPop exception as it will lead to better error handling with Gremlin Server and other parts of the stack.

rollback

void rollback()

Rolls back a transaction. This method may optionally throw TransactionException on error. Providers should consider wrapping their transaction exceptions in this TinkerPop exception as it will lead to better error handling with Gremlin Server and other parts of the stack.

createThreadedTx

<G extends Graph> G createThreadedTx()

Creates a transaction that can be executed across multiple threads. The Graph returned from this method is not meant to represent some form of child transaction that can be committed from this object. A threaded transaction is a Graph instance that has a transaction context that enables multiple threads to collaborate on the same transaction. A standard transactional context tied to a Graph that supports transactions will typically bind a transaction to a single thread via ThreadLocal.

isOpen

boolean isOpen()

Determines if a transaction is currently open.

readWrite

void readWrite()

An internal function that signals a read or a write has occurred - not meant to be called directly by end users.

close

void close()

Closes the transaction where the default close behavior defined by {onClose(Consumer)} will be executed.

Specified by:

close in interface AutoCloseable

onReadWrite

Transaction onReadWrite(Consumer<Transaction> consumer)

Describes how a transaction is started when a read or a write occurs. This value can be set using standard behaviors defined in Transaction.READ_WRITE_BEHAVIOR or a mapper Consumer function.

onClose

Transaction onClose(Consumer<Transaction> consumer)

Describes what happens to a transaction on a call to Graph.close(). This value can be set using standard behavior defined in Transaction.CLOSE_BEHAVIOR or a mapper Consumer function.

addTransactionListener

void addTransactionListener(Consumer<Transaction.Status> listener)

Adds a listener that is called back with a status when a commit or rollback is successful. It is expected that listeners be bound to the current thread as is standard for transactions. Therefore a listener registered in the current thread will not get callback events from a commit or rollback call in a different thread.

removeTransactionListener

void removeTransactionListener(Consumer<Transaction.Status> listener)

Removes a transaction listener.

clearTransactionListeners

void clearTransactionListeners()

Removes all transaction listeners.