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

Nested Classes

Modifier and Type	Interface and Description
static interface	ISMLocking.ReadLock
static interface	ISMLocking.WriteLock

Method Summary

Modifier and Type	Method and Description
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.