| java.lang.Object
 org.apache.derby.impl.services.locks.Lock
org.apache.derby.impl.services.locks.ActiveLock
| ActiveLock | | final public class ActiveLock extends Lock (Code) | | A Lock represents a granted or waiting lock request.
MT - Mutable - Immutable identity : Thread Aware
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| Field Summary | |
| protected boolean | canSkip
If true then this lock can be granted even if
it is not the first lock request on the wait queue. | | boolean | potentiallyGranted
Set to true if the Lock potentially could be granted. | | byte | wakeUpNow
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| Constructor Summary | |
| protected | ActiveLock(Object space, Lockable ref, Object qualifier)
Initialize the lock, should be seen as part of the constructor. |
| Method Summary | |
| protected void | clearPotentiallyGranted()
Clear the potentially granted flag. | | protected boolean | setPotentiallyGranted()
Set the potentially granted flag, returns true if the
flag changed its state. | | protected synchronized byte | waitForGrant(int timeout)
Wait for a lock to be granted, returns when the lock is granted.
The sleep wakeup scheme depends on the two booleans wakeUpNow & potentiallyGranted.
MT - Single thread required - and assumed to be the thread requesting the lock.
true if the wait ended early (ie. | | protected synchronized void | wakeUp(byte why)
Wake up anyone sleeping on this lock. |
| canSkip | | protected boolean canSkip(Code) | | If true then this lock can be granted even if
it is not the first lock request on the wait queue.
This can occur if the compatability space already holds
a lock on the object.
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| potentiallyGranted | | boolean potentiallyGranted(Code) | | Set to true if the Lock potentially could be granted.
MT - mutable - single thread required
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| wakeUpNow | | byte wakeUpNow(Code) | | Set to true if the object waiting on this thread should wake up,
MT - mutable - java synchronized(this)
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| ActiveLock | | protected ActiveLock(Object space, Lockable ref, Object qualifier)(Code) | | Initialize the lock, should be seen as part of the constructor. A future
version of this class may become mutable - mutable identity.
MT - single thread required
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| clearPotentiallyGranted | | protected void clearPotentiallyGranted()(Code) | | Clear the potentially granted flag.
MT - single thread required
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| setPotentiallyGranted | | protected boolean setPotentiallyGranted()(Code) | | Set the potentially granted flag, returns true if the
flag changed its state.
MT - single thread required
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| waitForGrant | | protected synchronized byte waitForGrant(int timeout) throws StandardException(Code) | | Wait for a lock to be granted, returns when the lock is granted.
The sleep wakeup scheme depends on the two booleans wakeUpNow & potentiallyGranted.
MT - Single thread required - and assumed to be the thread requesting the lock.
true if the wait ended early (ie. someone else woke us up).
exception:
StandardException - timeout, deadlock or thread interrupted |
| wakeUp | | protected synchronized void wakeUp(byte why)(Code) | | Wake up anyone sleeping on this lock.
MT - Thread Safe
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| Fields inherited from org.apache.derby.impl.services.locks.Lock | int count(Code)(Java Doc)
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