org.apache.jackrabbit.core.state
Interface ISMLocking

All Known Implementing Classes:

DefaultISMLocking, FineGrainedISMLocking

public interface ISMLocking

ISMLocking defines an interface for a locking strategy of an ItemStateManager.

An implementation of ISMLocking must meet the following requirements:

• While a read lock is held for a given item with id I an implementation must ensure that no write lock is issued for a change log that contains a reference to an item with id I.
• While a write lock is held for a given change log C an implementation must ensure that no read lock is issued for an item that is contained in C, unless the current thread is the owner of the write lock!
• While a write lock is held for a given change log C an implementation must ensure that no write lock is issued for a change log C' that intersects with C. That is both change logs contain a reference to the same item. Please note that an implementation is free to block requests entirely for additional write lock while a write lock is active. It is not a requirement to support concurrent write locks.
• While a write lock is held for a change log C, the holder of the write lock (and any related threads) needs to be able to acquire a read lock even if other writers are waiting for the lock. This behaviour must continue also when the write lock has been downgraded. Note that it is not necessary for a holder of a read lock to be able to upgrade to a write lock.

Nested Class Summary

static interface	ISMLocking.ReadLock
static interface	ISMLocking.WriteLock

Method Summary

ISMLocking.ReadLock	acquireReadLock(ItemId id) Acquire a read lock for the given item id.
ISMLocking.WriteLock	acquireWriteLock(ChangeLog changeLog) Acquires a write lock for the given changeLog.

Method Detail

acquireReadLock

ISMLocking.ReadLock acquireReadLock(ItemId id)
                                    throws InterruptedException

Acquire a read lock for the given item id.

Parameters:

id - an item id.

Throws:

InterruptedException

acquireWriteLock

ISMLocking.WriteLock acquireWriteLock(ChangeLog changeLog)
                                      throws InterruptedException

Acquires a write lock for the given changeLog.

Parameters:

changeLog - the change log

Returns:

the write lock for the given changeLog.

Throws:

InterruptedException - if the thread is interrupted while creating the write lock.