org.apache.derby.impl.store.raw.xact

Class ContainerLocking2

java.lang.Object

org.apache.derby.impl.store.raw.xact.ContainerLocking2

All Implemented Interfaces:

LockingPolicy

public class ContainerLocking2
extends java.lang.Object

A locking policy that implements container level locking with isolation degree 2.

See Also:

LockingPolicy

Field Summary

Fields inherited from interface org.apache.derby.iapi.store.raw.LockingPolicy

MODE_CONTAINER, MODE_NONE, MODE_RECORD

Method Summary

Modifier and Type	Method and Description
int	getMode() Get the mode of this policy
boolean	lockContainer(Transaction t, ContainerHandle container, boolean waitForLock, boolean forUpdate) Obtain a Container shared or exclusive lock until the end of the nested transaction.
boolean	lockRecordForRead(Transaction t, ContainerHandle container, RecordHandle record, boolean waitForLock, boolean forUpdate) Called before a record is fetched.
boolean	lockRecordForWrite(Transaction t, RecordHandle record, boolean lockForInsert, boolean waitForLock) Called before a record is inserted, updated or deleted.
void	unlockContainer(Transaction t, ContainerHandle container) Unlock read locks.
void	unlockRecordAfterRead(Transaction t, ContainerHandle container, RecordHandle record, boolean forUpdate, boolean row_qualified) Called after a record has been fetched.
boolean	zeroDurationLockRecordForWrite(Transaction t, RecordHandle record, boolean lockForPreviousKey, boolean waitForLock) Request a write lock which will be released immediately upon grant.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

lockContainer

public boolean lockContainer(Transaction t,
                             ContainerHandle container,
                             boolean waitForLock,
                             boolean forUpdate)
                      throws StandardException

Obtain a Container shared or exclusive lock until the end of the nested transaction.

Specified by:

lockContainer in interface LockingPolicy

Parameters:

t - Transaction to associate lock with.

container - Container to lock.

waitForLock - Should lock request wait until granted?

forUpdate - Should container be locked for update, or read?

Returns:

true if the lock was obtained, false if it wasn't. False should only be returned if the waitForLock policy was set to "false," and the lock was unavailable.

Throws:

StandardException - Standard Derby error policy

See Also:

ContainerHandle

unlockContainer

public void unlockContainer(Transaction t,
                            ContainerHandle container)

Unlock read locks.

In Cursor stability release all read locks obtained. unlockContainer() will be called when the container is closed.

Specified by:

unlockContainer in interface LockingPolicy

Parameters:

t - The transaction to associate the lock with.

container - Container to unlock.

See Also:

ContainerHandle, ContainerHandle.close()

getMode

public int getMode()

Description copied from interface: LockingPolicy

Get the mode of this policy

Specified by:

getMode in interface LockingPolicy

lockRecordForRead

public boolean lockRecordForRead(Transaction t,
                                 ContainerHandle container,
                                 RecordHandle record,
                                 boolean waitForLock,
                                 boolean forUpdate)
                          throws StandardException

Description copied from interface: LockingPolicy

Called before a record is fetched.

Specified by:

lockRecordForRead in interface LockingPolicy

Parameters:

t - Transaction to associate lock with.

container - Open Container used to get record. Will be used to row locks by the container they belong to.

record - Record to lock.

waitForLock - Should lock request wait until granted?

forUpdate - Should container be locked for update, or read?

Throws:

StandardException - Standard Derby error policy

See Also:

Page

zeroDurationLockRecordForWrite

public boolean zeroDurationLockRecordForWrite(Transaction t,
                                              RecordHandle record,
                                              boolean lockForPreviousKey,
                                              boolean waitForLock)
                                       throws StandardException

Description copied from interface: LockingPolicy

Request a write lock which will be released immediately upon grant.

Specified by:

zeroDurationLockRecordForWrite in interface LockingPolicy

Parameters:

t - Transaction to associate lock with.

record - Record to lock.

lockForPreviousKey - Lock is for a previous key of a insert.

waitForLock - Should lock request wait until granted?

Returns:

true if the lock was obtained, false if it wasn't. False should only be returned if the waitForLock argument was set to "false," and the lock was unavailable.

Throws:

StandardException - Standard Derby error policy

See Also:

Page

lockRecordForWrite

public boolean lockRecordForWrite(Transaction t,
                                  RecordHandle record,
                                  boolean lockForInsert,
                                  boolean waitForLock)
                           throws StandardException

Description copied from interface: LockingPolicy

Called before a record is inserted, updated or deleted. If zeroDuration is true then lock is released immediately after it has been granted.

Specified by:

lockRecordForWrite in interface LockingPolicy

Parameters:

t - Transaction to associate lock with.

record - Record to lock.

lockForInsert - Lock is for an insert.

waitForLock - Should lock request wait until granted?

Returns:

true if the lock was obtained, false if it wasn't. False should only be returned if the waitForLock argument was set to "false," and the lock was unavailable.

Throws:

StandardException - Standard Derby error policy

See Also:

Page

unlockRecordAfterRead

public void unlockRecordAfterRead(Transaction t,
                                  ContainerHandle container,
                                  RecordHandle record,
                                  boolean forUpdate,
                                  boolean row_qualified)
                           throws StandardException

Description copied from interface: LockingPolicy

Called after a record has been fetched.

Specified by:

unlockRecordAfterRead in interface LockingPolicy

Throws:

StandardException - Standard Derby error policy

See Also:

Page