| java.lang.Object
 org.apache.commons.transaction.locking.GenericLockManager
All known Subclasses: org.apache.commons.transaction.locking.ReadWriteLockManager,
| GenericLockManager | | public class GenericLockManager implements LockManager,LockManager2(Code) | | Manager for
GenericLock s on resources. This implementation includes
- deadlock detection, which is configurable to come into effect after an initial short waiting
lock request; this is useful as it is somewhat expensive
- global transaction timeouts that actively revoke granted rights from transactions
version:
$Id: GenericLockManager.java 493628 2007-01-07 01:42:48Z joerg $ |
| Method Summary | |
| protected void | addOwner(Object ownerId, GenericLock lock)
| | public MultiLevelLock | atomicGetOrCreateLock(Object resourceId)
| | public boolean | checkLock(Object ownerId, Object resourceId, int targetLockLevel, boolean reentrant)
| | protected GenericLock | createLock(Object resourceId)
| | protected void | doLock(GenericLock lock, Object ownerId, Object resourceId, int targetLockLevel, int compatibility, boolean preferred, long timeoutMSecs)
| | public Set | getAll(Object ownerId)
| | public int | getLevel(Object ownerId, Object resourceId)
| | public MultiLevelLock | getLock(Object resourceId)
| | public Collection | getLocks()
Gets all locks as orignials, no copies. | | protected long | getNextGlobalConflictTimeout(Set conflicts)
| | public boolean | hasLock(Object ownerId, Object resourceId, int lockLevel)
| | public void | lock(Object ownerId, Object resourceId, int targetLockLevel, boolean reentrant)
| | public void | lock(Object ownerId, Object resourceId, int targetLockLevel, boolean reentrant, long timeoutMSecs)
| | public void | lock(Object ownerId, Object resourceId, int targetLockLevel, int compatibility, boolean preferred, long timeoutMSecs)
| | public boolean | release(Object ownerId, Object resourceId)
| | public void | releaseAll(Object ownerId)
| | protected void | releaseAllNoTimeOutReset(Object ownerId)
| | protected boolean | releaseTimedOutOwners()
| | public void | removeLock(MultiLevelLock lock)
| | protected void | removeOwner(Object ownerId, GenericLock lock)
| | public void | startGlobalTimeout(Object ownerId, long timeoutMSecs)
| | protected boolean | timeOut(Object ownerId)
| | protected void | timeoutCheck(Object ownerId)
| | public synchronized String | toString()
| | public boolean | tryLock(Object ownerId, Object resourceId, int targetLockLevel, boolean reentrant)
| | protected boolean | wouldDeadlock(Object ownerId, Set path)
Checks if an owner is deadlocked. |
| DEFAULT_CHECK_THRESHHOLD | | final public static long DEFAULT_CHECK_THRESHHOLD(Code) | | |
| DEFAULT_TIMEOUT | | final public static long DEFAULT_TIMEOUT(Code) | | |
| checkThreshhold | | protected long checkThreshhold(Code) | | |
| effectiveGlobalTimeouts | | protected Map effectiveGlobalTimeouts(Code) | | Maps onwerId to global effective time outs (i.e. the time the lock will time out).
|
| globalLocks | | protected Map globalLocks(Code) | | Maps resourceId to lock.
|
| globalOwners | | protected Map globalOwners(Code) | | Maps onwerId to locks it (partially) owns.
|
| globalTimeoutMSecs | | protected long globalTimeoutMSecs(Code) | | |
| maxLockLevel | | protected int maxLockLevel(Code) | | |
| timedOutOwners | | protected Set timedOutOwners(Code) | | |
| GenericLockManager | | public GenericLockManager(int maxLockLevel, LoggerFacade logger, long timeoutMSecs, long checkThreshholdMSecs) throws IllegalArgumentException(Code) | | Creates a new generic lock manager.
Parameters:
maxLockLevel - highest allowed lock level as described in GenericLock's class intro
Parameters:
logger - generic logger used for all kind of debug logging
Parameters:
timeoutMSecs - specifies the maximum time to wait for a lock in milliseconds
Parameters:
checkThreshholdMSecs - specifies a special wait threshhold before deadlock andtimeout detection come into play or -1 switchit off and check for directly
throws:
IllegalArgumentException - if maxLockLevel is less than 1
since:
1.1 |
| doLock | | protected void doLock(GenericLock lock, Object ownerId, Object resourceId, int targetLockLevel, int compatibility, boolean preferred, long timeoutMSecs)(Code) | | |
| getLocks | | public Collection getLocks()(Code) | | Gets all locks as orignials, no copies.
collection holding all locks. |
| getNextGlobalConflictTimeout | | protected long getNextGlobalConflictTimeout(Set conflicts)(Code) | | |
| releaseAllNoTimeOutReset | | protected void releaseAllNoTimeOutReset(Object ownerId)(Code) | | |
| releaseTimedOutOwners | | protected boolean releaseTimedOutOwners()(Code) | | |
| wouldDeadlock | | protected boolean wouldDeadlock(Object ownerId, Set path)(Code) | | Checks if an owner is deadlocked.
We traverse the tree recursively formed by owners, locks held by them and
then again owners waiting for the locks. If there is a cycle in one of
the paths from the root to a leaf we have a deadlock.
A more detailed discussion on deadlocks and definitions and how to detect
them can be found in this
nice article .
Caution: This computation can be very expensive with many
owners and locks. Worst (unlikely) case is exponential.
Parameters:
ownerId - the owner to check for being deadlocked
Parameters:
path - initially should be called with an empty set true if the owner is deadlocked,false otherwise |
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