locklib

Class Target<LockType>

java.lang.Object

locklib.Target<LockType>

Type Parameters:

LockType - the type of locks used by this target

public class Target<LockType>
extends Object

A target is an object that can be locked. Targets can be arranged hierarchically. Locking a target may impose locks on its parent targets, depending on the LockPolicy present in the LockManager.

Constructor Summary

Constructors

Constructor and Description
Target(LockManager<LockType> lm) Creates a new target.
Target(Target<LockType> parent) Creates a new target, child of an existing parent.

Method Summary

Modifier and Type	Method and Description
Set<Target<LockType>>	children() Obtains the set of all children (non-recursive) of this target.
LockGrantFuture<LockType>	lock(LockRequest<LockType> request) Requests an asynchronous lock of this target.
Target<LockType>	parent() Obtains the parent of this target.
void	parent(Target<LockType> p) Sets the parent target of this target.
void	unlock(LockGrant<LockType> g) Unlocks a target, which must have been previously locked.

Methods inherited from class java.lang.Object

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

Constructor Detail

Target

public Target(LockManager<LockType> lm)

Creates a new target.

Parameters:

lm - the target's lock manager

Target

public Target(Target<LockType> parent)

Creates a new target, child of an existing parent.

Parameters:

parent - the target's parent

Method Detail

parent

public void parent(Target<LockType> p)

Sets the parent target of this target. Invoking this method does not add or remove any locks from either this target, its current parent (if any) or its new parent (if any).

Parameters:

p - the parent target or null if this target should not have a parent

Throws:

CyclicTargetHierarchyException - setting the parent as p would yield a cycle

parent

public Target<LockType> parent()

Obtains the parent of this target.

Returns:

the parent or null if none

children

public Set<Target<LockType>> children()

Obtains the set of all children (non-recursive) of this target.

Returns:

all children

lock

public LockGrantFuture<LockType> lock(LockRequest<LockType> request)

Requests an asynchronous lock of this target. This method will return immediately. The LockGrantFuture.get() method (or its timed variant) may be used to wait for the lock to be acquired.

This method will create a chain starting from the top of the hierarchy of this target up to this target.

Parameters:

request - the lock request which may not be already acquired

Returns:

the lock grant information

unlock

public void unlock(LockGrant<LockType> g)

Unlocks a target, which must have been previously locked. This method releases all locks a holder has in this target.

Parameters:

g - the lock grant

Throws:

NotLockedException - the lock is not locked or was unlocked concurrently during execution of this operation