org.apache.oozie.service

Class MemoryLocksService

java.lang.Object

org.apache.oozie.service.MemoryLocksService

All Implemented Interfaces:

Service, Instrumentable

Direct Known Subclasses:

ZKLocksService

public class MemoryLocksService
extends Object
implements Service, Instrumentable

Service that provides in-memory locks. Assumes no other Oozie servers are using the database.

Field Summary

Fields

Modifier and Type	Field and Description
protected static String	INSTRUMENTATION_GROUP

Fields inherited from interface org.apache.oozie.service.Service

CONF_PREFIX, DEFAULT_LOCK_TIMEOUT, lockTimeout, USE_XCOMMAND

Constructor Summary

Constructors

Constructor and Description
MemoryLocksService()

Method Summary

Methods

Modifier and Type	Method and Description
void	destroy() Destroy the memory locks service.
Class<? extends Service>	getInterface() Return the public interface for the memory locks services
LockToken	getReadLock(String resource, long wait) Obtain a READ lock for a source.
LockToken	getWriteLock(String resource, long wait) Obtain a WRITE lock for a source.
void	init(Services services) Initialize the memory locks service
void	instrument(Instrumentation instr) Instruments the memory locks service.

Methods inherited from class java.lang.Object

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

Field Detail

INSTRUMENTATION_GROUP

protected static final String INSTRUMENTATION_GROUP

See Also:

Constant Field Values

Constructor Detail

MemoryLocksService

public MemoryLocksService()

Method Detail

init

public void init(Services services)
          throws ServiceException

Initialize the memory locks service

Specified by:

init in interface Service

Parameters:

services - services instance.

Throws:

ServiceException - thrown if the service could not initialize.

destroy

public void destroy()

Destroy the memory locks service.

Specified by:

destroy in interface Service

getInterface

public Class<? extends Service> getInterface()

Return the public interface for the memory locks services

Specified by:

getInterface in interface Service

Returns:

MemoryLocksService.

instrument

public void instrument(Instrumentation instr)

Instruments the memory locks service.

Specified by:

instrument in interface Instrumentable

Parameters:

instr - instance to instrument the memory locks service to.

getReadLock

public LockToken getReadLock(String resource,
                    long wait)
                      throws InterruptedException

Obtain a READ lock for a source.

Parameters:

resource - resource name.

wait - time out in milliseconds to wait for the lock, -1 means no timeout and 0 no wait.

Returns:

the lock token for the resource, or null if the lock could not be obtained.

Throws:

InterruptedException - thrown if the thread was interrupted while waiting.

getWriteLock

public LockToken getWriteLock(String resource,
                     long wait)
                       throws InterruptedException

Obtain a WRITE lock for a source.

Parameters:

resource - resource name.

wait - time out in milliseconds to wait for the lock, -1 means no timeout and 0 no wait.

Returns:

the lock token for the resource, or null if the lock could not be obtained.

Throws:

InterruptedException - thrown if the thread was interrupted while waiting.