net.deelam.graphtools

Class GraphTransaction

java.lang.Object

net.deelam.graphtools.GraphTransaction

public class GraphTransaction
extends Object

This class does not create new objects. Each begin() call must have a corresponding commit() or rollback() for all execution paths, including exceptions. Best practice is to surround transactions with a try-catch block.

                int tx=GraphTransaction.begin(graph);
                try{
                        doYourGraphOperations(graph);
                        doNestedTransaction(graph);  // contains calls to begin(), commit(), and maybe rollback()
                        GraphTransaction.commit(tx);
                }catch(ExpectedException re){
                        // expect exception be thrown
                        GraphTransaction.rollback(tx);
                        throw re;
                }
 

If doNestedTransaction() throws an uncaught exception (which means rollback() was not called), GraphTransaction will handle it properly given the tx parameter. Supports nested transactions. When any of the nested transactions calls rollback(), graph.rollback() actually occurs in the outermost transaction when commit() or rollback() is called.

Author:

deelam

Field Summary

Fields

Modifier and Type	Field and Description
protected static ThreadLocal<com.tinkerpop.blueprints.TransactionalGraph>	graphHolder
protected static ThreadLocal<org.apache.commons.lang.mutable.MutableInt>	nestingCounter
protected static ThreadLocal<AtomicBoolean>	rollbackCalled

Constructor Summary

Constructors

Constructor and Description
GraphTransaction()

Method Summary

Methods

Modifier and Type	Method and Description
static int	begin(com.tinkerpop.blueprints.TransactionalGraph currGraph)
static void	checkTransactionsClosed()
static boolean	commit(int tx)
static boolean	isInTransaction()
static boolean	isOuterMostTransaction()
static boolean	rollback(int tx) Assumes commit() will not be called for the corresponding begin() associated with this transaction.

Methods inherited from class java.lang.Object

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

Field Detail

graphHolder

protected static final ThreadLocal<com.tinkerpop.blueprints.TransactionalGraph> graphHolder

nestingCounter

protected static final ThreadLocal<org.apache.commons.lang.mutable.MutableInt> nestingCounter

rollbackCalled

protected static final ThreadLocal<AtomicBoolean> rollbackCalled

Constructor Detail

GraphTransaction

public GraphTransaction()

Method Detail

begin

public static int begin(com.tinkerpop.blueprints.TransactionalGraph currGraph)

Returns:

depth of transaction.

rollback

public static boolean rollback(int tx)

Assumes commit() will not be called for the corresponding begin() associated with this transaction.

Returns:

if rollback actually occurred. False means transaction is nested, and rollback is delayed until the top-level transaction is committed or rolledback.

commit

public static boolean commit(int tx)

Returns:

if top-level transaction was closed without rollback. False means (1) transaction was nested and is still open, or (2) rollback was called.

isInTransaction

public static boolean isInTransaction()

isOuterMostTransaction

public static boolean isOuterMostTransaction()

checkTransactionsClosed

public static void checkTransactionsClosed()