com.sleepycat.je.txn

Class LockUpgrade

java.lang.Object

com.sleepycat.je.txn.LockUpgrade

 class LockUpgrade
extends java.lang.Object

LockUpgrade is a type safe enumeration of lock upgrade types. Methods on LockUpgrade objects are used to determine whether an upgrade is needed and, if so, how it should be handled.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) static LockUpgrade	EXISTING
(package private) static LockUpgrade	ILLEGAL
(package private) static LockUpgrade	RANGE_READ_IMMED
(package private) static LockUpgrade	RANGE_WRITE_IMMED
(package private) static LockUpgrade	RANGE_WRITE_PROMOTE
(package private) static LockUpgrade	WRITE_PROMOTE

Method Summary

Methods

Modifier and Type	Method and Description
(package private) boolean	getIllegal() This method is called to determine whether the upgrade is illegal.
(package private) boolean	getPromotion() This method is called when getUpgrade returns non-null to determine whether the upgrade is a true promotion or can be granted immediately.
(package private) LockType	getUpgrade() This method is called first to determine whether an upgrade to a new lock type is needed, and what the new lock type should be.

Methods inherited from class java.lang.Object

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

Field Detail

ILLEGAL

static final LockUpgrade ILLEGAL

EXISTING

static final LockUpgrade EXISTING

WRITE_PROMOTE

static final LockUpgrade WRITE_PROMOTE

RANGE_READ_IMMED

static final LockUpgrade RANGE_READ_IMMED

RANGE_WRITE_IMMED

static final LockUpgrade RANGE_WRITE_IMMED

RANGE_WRITE_PROMOTE

static final LockUpgrade RANGE_WRITE_PROMOTE

Method Detail

getIllegal

boolean getIllegal()

This method is called to determine whether the upgrade is illegal. If true is returned, an internal error has occurred. This should never happen since RANGE_INSERT should never be requested along with other locks by the same locker; a separate locker is used for RANGE_INSERT locks.

getUpgrade

LockType getUpgrade()

This method is called first to determine whether an upgrade to a new lock type is needed, and what the new lock type should be. If null is returned, the existing lock should be unchanged and no upgrade is needed. If non-null is returned, an upgrade to the returned type should be performed; in this case, call getPromotion to determine how to do the upgrade.

getPromotion

boolean getPromotion()

This method is called when getUpgrade returns non-null to determine whether the upgrade is a true promotion or can be granted immediately. A true promotion is a change from read to write locking, and may require waiting if the write lock conflicts with a lock held by another locker. An upgrade that is not a promotion is just a type change, and never causes a lock conflict.