com.bigdata.concurrent

Class LockManagerTask<R extends Comparable<R>,T>

java.lang.Object

com.bigdata.concurrent.LockManagerTask<R,T>

All Implemented Interfaces:

Callable<T>

public class LockManagerTask<R extends Comparable<R>,T>
extends Object
implements Callable<T>

Class encapsulates handshaking with the LockManager for an operation requiring exclusive access to one or more resources and that are willing to pre-declare their resource requirements.

Version:

$Id$

Author:

Bryan Thompson

Field Summary

Fields

Modifier and Type	Field and Description
protected static boolean	INFO
protected static org.apache.log4j.Logger	log

Constructor Summary

Constructors

Constructor and Description
LockManagerTask(LockManager<R> lockManager, R[] resource, Callable<T> target)

Method Summary

Methods

Modifier and Type	Method and Description
T	call() Acquires pre-declared locks and then runs the operation identified to the constructor.
long	getLockLatency() The elapsed nanoseconds the task waited to acquire its locks.
LockManager<R>	getLockManager() The LockManager.
long	getLockTimeout() The timeout (milliseconds) or ZERO (0L) for an infinite timeout.
int	getMaxLockTries() The maximum #of times that the task will attempt to acquire its locks (positive integer).
R[]	getResource() The resource(s) that are pre-declared by the task.
long	setLockTimeout(long newValue)
int	setMaxLockTries(int newValue)
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

log

protected static final org.apache.log4j.Logger log

INFO

protected static final boolean INFO

Constructor Detail

LockManagerTask

public LockManagerTask(LockManager<R> lockManager,
               R[] resource,
               Callable<T> target)

Parameters:

lockManager - The lock manager.

resource - The resource(s) to be locked.

target - The Runnable target that will be invoked iff the locks are successfully acquired.

Method Detail

getLockManager

public LockManager<R> getLockManager()

The LockManager.

getResource

public R[] getResource()

The resource(s) that are pre-declared by the task. call() will ensure that the task as a lock on these resources before it invokes #run() to execution the task.

setMaxLockTries

public int setMaxLockTries(int newValue)

getLockLatency

public long getLockLatency()

The elapsed nanoseconds the task waited to acquire its locks.

getMaxLockTries

public int getMaxLockTries()

The maximum #of times that the task will attempt to acquire its locks (positive integer).

setLockTimeout

public long setLockTimeout(long newValue)

getLockTimeout

public long getLockTimeout()

The timeout (milliseconds) or ZERO (0L) for an infinite timeout.

call

public final T call()
             throws Exception

Acquires pre-declared locks and then runs the operation identified to the constructor.

Specified by:

call in interface Callable<T>

Returns:

null

Throws:

Exception - if something goes wrong.

InterruptedException - if the current thread is interrupted.

toString

public String toString()

Overrides:

toString in class Object