net.sf.ehcache.transaction
Interface SoftLock

All Known Implementing Classes:

ReadCommittedSoftLockImpl

public interface SoftLock

A soft lock is used to lock elements in transactional stores

Author:

Ludovic Orban

Method Summary

void	clearTryLock() Clear the state of the soft lock after a tryLock() call succeeded.
void	freeze() Freeze the soft lock.
Element	getElement(TransactionID currentTransactionId) Get the element the current transaction is supposed to see.
Element	getFrozenElement() Get the Element with which this soft lock should be replaced by a commit, rollback or clean up
Object	getKey() Get the key of the element this soft lock is guarding
TransactionID	getTransactionID() Get the ID of the transaction under which this soft lock is operating
boolean	isExpired() Check if the soft lock expired, ie: that the thread which locked it died
void	lock() Lock the soft lock
boolean	tryLock(long ms) Attempt to lock the soft lock
void	unfreeze() Unfreeze the soft lock
void	unlock() Unlock the soft lock.
Element	updateElement(Element element) Change the Element at the key this soft lock is guarding

Method Detail

getKey

Object getKey()

Get the key of the element this soft lock is guarding

Returns:

the key

getTransactionID

TransactionID getTransactionID()

Get the ID of the transaction under which this soft lock is operating

Returns:

the TransactionID

getElement

Element getElement(TransactionID currentTransactionId)

Get the element the current transaction is supposed to see.

Parameters:

currentTransactionId - the current transaction under which this call is executed

Returns:

the Element visible to the current transaction

updateElement

Element updateElement(Element element)

Change the Element at the key this soft lock is guarding

Parameters:

element - the new Element

Returns:

the previous Element

lock

void lock()

Lock the soft lock

tryLock

boolean tryLock(long ms)
                throws InterruptedException

Attempt to lock the soft lock

Parameters:

ms - the time in milliseconds before this method gives up

Returns:

true if the soft lock was locked, false otherwise

Throws:

InterruptedException - if the thread calling this method was interrupted

clearTryLock

void clearTryLock()

Clear the state of the soft lock after a tryLock() call succeeded.

unlock

void unlock()

Unlock the soft lock. Once a soft lock got unlocked, it is considered 'dead': it cannot be locked again and must be cleaned up

freeze

void freeze()

Freeze the soft lock. A soft lock should only be frozen for a very short period of time as this blocks the getElement(TransactionID) method calls. Freeze is used to mark the start of a commit / rollback phase

unfreeze

void unfreeze()

Unfreeze the soft lock

isExpired

boolean isExpired()

Check if the soft lock expired, ie: that the thread which locked it died

Returns:

true if the soft lock is orphan and should be cleaned up, false otherwise

getFrozenElement

Element getFrozenElement()

Get the Element with which this soft lock should be replaced by a commit, rollback or clean up

Returns:

the Element