org.quartz.impl.jdbcjobstore

Class JTANonClusteredSemaphore

java.lang.Object

org.quartz.impl.jdbcjobstore.JTANonClusteredSemaphore

All Implemented Interfaces:

Semaphore

public class JTANonClusteredSemaphore
extends java.lang.Object
implements Semaphore

Provides in memory thread/resource locking that is JTA Transaction aware. It is most appropriate for use when using JobStoreCMT without clustering.

This Semaphore implementation is not Quartz cluster safe.

When a lock is obtained/released but there is no active JTA Transaction, then this Semaphore operates just like SimpleSemaphore.

By default, this class looks for the TransactionManager in JNDI under name "java:TransactionManager". If this is not where your Application Server registers it, you can modify the JNDI lookup location using the "transactionManagerJNDIName" property.

IMPORTANT: This Semaphore implementation is currently experimental. It has been tested a limited amount on JBoss 4.0.3SP1. If you do choose to use it, any feedback would be most appreciated!

See Also:

SimpleSemaphore

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	DEFAULT_TRANSACTION_MANANGER_LOCATION

Constructor Summary

Constructors

Constructor and Description
JTANonClusteredSemaphore()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	isLockOwner(java.sql.Connection conn, java.lang.String lockName) Determine whether the calling thread owns a lock on the identified resource.
boolean	obtainLock(java.sql.Connection conn, java.lang.String lockName) Grants a lock on the identified resource to the calling thread (blocking until it is available).
void	releaseLock(java.sql.Connection conn, java.lang.String lockName) Release the lock on the identified resource if it is held by the calling thread, unless currently in a JTA transaction.
boolean	requiresConnection() This Semaphore implementation does not use the database.
void	setTransactionManagerJNDIName(java.lang.String transactionManagerJNDIName)

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_TRANSACTION_MANANGER_LOCATION

public static final java.lang.String DEFAULT_TRANSACTION_MANANGER_LOCATION

See Also:

Constant Field Values

Constructor Detail

JTANonClusteredSemaphore

public JTANonClusteredSemaphore()

Method Detail

setTransactionManagerJNDIName

public void setTransactionManagerJNDIName(java.lang.String transactionManagerJNDIName)

obtainLock

public boolean obtainLock(java.sql.Connection conn,
                 java.lang.String lockName)
                   throws LockException

Grants a lock on the identified resource to the calling thread (blocking until it is available).

Specified by:

obtainLock in interface Semaphore

Parameters:

conn - Database connection used to establish lock. Can be null if Semaphore.requiresConnection() returns false.

Returns:

true if the lock was obtained.

Throws:

LockException

releaseLock

public void releaseLock(java.sql.Connection conn,
               java.lang.String lockName)
                 throws LockException

Release the lock on the identified resource if it is held by the calling thread, unless currently in a JTA transaction.

Specified by:

releaseLock in interface Semaphore

Parameters:

conn - Database connection used to establish lock. Can be null if Semaphore.requiresConnection() returns false.

Throws:

LockException

isLockOwner

public boolean isLockOwner(java.sql.Connection conn,
                  java.lang.String lockName)

Determine whether the calling thread owns a lock on the identified resource.

Specified by:

isLockOwner in interface Semaphore

Parameters:

conn - Database connection used to establish lock. Can be null if Semaphore.requiresConnection() returns false.

requiresConnection

public boolean requiresConnection()

This Semaphore implementation does not use the database.

Specified by:

requiresConnection in interface Semaphore

See Also:

Semaphore.isLockOwner(Connection, String), Semaphore.obtainLock(Connection, String), Semaphore.releaseLock(Connection, String)