Class RowLocking3Escalate

java.lang.Object

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

org.apache.derby.impl.store.raw.xact.ContainerLocking3

org.apache.derby.impl.store.raw.xact.RowLocking3Escalate

All Implemented Interfaces:

LockingPolicy

public class RowLocking3Escalate
extends ContainerLocking3

A locking policy that implements row level locking with isolation degree 3.

See Also:

• LockingPolicy

Field Summary

Fields inherited from class ContainerLocking3

lf

Fields inherited from interface LockingPolicy

MODE_CONTAINER, MODE_NONE, MODE_RECORD

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	RowLocking3Escalate(LockFactory lf)

Method Summary

Modifier and Type	Method	Description
boolean	lockContainer(Transaction t, ContainerHandle container, boolean waitForLock, boolean forUpdate)	Escalates Row Locking 3 to Container Locking 3.

Methods inherited from class ContainerLocking3

getMode

Methods inherited from class NoLocking

lockRecordForRead, lockRecordForWrite, unlockContainer, unlockRecordAfterRead, zeroDurationLockRecordForWrite

Methods inherited from class Object

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

Constructor Details

RowLocking3Escalate

protected RowLocking3Escalate(LockFactory lf)

Method Details

lockContainer

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

Escalates Row Locking 3 to Container Locking 3.

This call is made by code which tracks the number of locks on a container. When the number of locks exceeds the escalate threshold the caller creates this new locking policy, calls lockContainer(), and substitues it for the old locking policy. The lockContainer call determines which table lock to get (S or X), gets that table lock, and then releases the row locks on the table. It is assumed that this is called on a open container for lock only.

Specified by:

lockContainer in interface LockingPolicy

Overrides:

lockContainer in class ContainerLocking3

Parameters:

t - Transaction to associate lock with.

container - Container to lock.

waitForLock - Ignored - will never wait for a lock.

forUpdate - Ignored, mode determined from current lock state.

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 exception policy.

See Also:

• ContainerHandle