i3.dragos.core.services.transactions.localmgr
Class LocalTransactionManager

java.lang.Object
  i3.dragos.core.services.transactions.localmgr.LocalTransactionManager

All Implemented Interfaces:

TransactionManager

public class LocalTransactionManager
extends java.lang.Object
implements TransactionManager

A custom TransactionManager implementation. Supports nested transactions as well as transactions distributed across multiple GraphPools.

Author:

Ernest Hammerschmidt <ernest@i3.informatik.rwth-aachen.de>, Thorsten Hermes <thermes@i3.informatik.rwth-aachen.de>

Field Summary

static java.lang.String

IMPLEMENTATION_NAME This implementation's descriptive name

Constructor Summary

LocalTransactionManager(DataSourceURL[] dataSourceURLs)
Creates a new LocalTransactionManager (required constructor for reflection).

Method Summary

void	acquireCommitSemaphore() Acquires the commit semaphore for this thread.
Transaction	createTransaction() Creates a Transaction object for the specific implementation.
protected LocalTransaction	createTransaction0(DataSource[] ds, LocalTransaction parentTransaction) Factory method for transactions.
Transaction	getCurrentTransaction() Gets the currently active Transaction, if any.
java.util.Collection<DataSourceURL>	getManagedDataSources() Returns a Collection of DataSourceURLs for all GraphPools managed by this TransactionManager.
void	releaseCommitSemaphore() Releases the commit semaphore for this thread.
void	removeTransaction() Removes a transaction from the map.
Transaction	requestTransaction() Gets the currently active Transaction or initializes a new one if none is currently active.

Methods inherited from class java.lang.Object

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

Field Detail

IMPLEMENTATION_NAME

public static final java.lang.String IMPLEMENTATION_NAME

This implementation's descriptive name

See Also:

Constant Field Values

Constructor Detail

LocalTransactionManager

public LocalTransactionManager(DataSourceURL[] dataSourceURLs)
                        throws TransactionManagerException

Creates a new LocalTransactionManager (required constructor for reflection).

Parameters:

dataSourceURLs - The URLs of the DataSources to operate on.

Throws:

TransactionManagerException - if the supplied array is empty or contains a null value.

Method Detail

getManagedDataSources

public java.util.Collection<DataSourceURL> getManagedDataSources()
                                                          throws TransactionException

Returns a Collection of DataSourceURLs for all GraphPools managed by this TransactionManager.

Specified by:

getManagedDataSources in interface TransactionManager

Returns:

a Collection of DataSourceURLs for all GraphPools managed by this TransactionManager.

Throws:

TransactionException - if something goes wrong.

createTransaction

public Transaction createTransaction()
                              throws TransactionException

Creates a Transaction object for the specific implementation. If a transaction is already active, this creates either a nested transaction or throws an exception (if nested transactions are not supported).

Specified by:

createTransaction in interface TransactionManager

Returns:

a Transaction instance (never null).

Throws:

TransactionException - if something goes wrong.

getCurrentTransaction

public Transaction getCurrentTransaction()
                                  throws TransactionException

Gets the currently active Transaction, if any.

A transaction is considered the current one if it is not in state Transaction.State.PRECOMMIT, Transaction.State.COMMITTED or Transaction.State.ROLLED_BACK, and has no active nested transactions.

Specified by:

getCurrentTransaction in interface TransactionManager

Returns:

a Transaction instance or null if none is active at the moment.

Throws:

TransactionException - if something goes wrong.

requestTransaction

public Transaction requestTransaction()
                               throws TransactionException

Gets the currently active Transaction or initializes a new one if none is currently active.

This convenience method is a simple combination of TransactionManager.getCurrentTransaction() with an optional TransactionManager.createTransaction().

Specified by:

requestTransaction in interface TransactionManager

Returns:

a Transaction instance (never null).

Throws:

TransactionException - if something goes wrong.

removeTransaction

public void removeTransaction()

Removes a transaction from the map. Called whenever a top-level transaction finishes (commit or rollback).

acquireCommitSemaphore

public void acquireCommitSemaphore()

Acquires the commit semaphore for this thread.

releaseCommitSemaphore

public void releaseCommitSemaphore()

Releases the commit semaphore for this thread.

createTransaction0

protected LocalTransaction createTransaction0(DataSource[] ds,
                                              LocalTransaction parentTransaction)
                                       throws TransactionException

Factory method for transactions.

Parameters:

ds - DataSource to work with.

parentTransaction - parent transaction if any.

Returns:

the new transaction.

Throws:

TransactionException - if the DataSourceTransaction could not be created.