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org.hibernate

public final Enum LockMode

extends Enum<LockMode>
Class Inheritance
Instances represent a lock mode for a row of a relational database table. It is not intended that users spend much time worrying about locking since Hibernate usually obtains exactly the right lock level automatically. Some "advanced" users may wish to explicitly specify lock levels.
Author
Gavin King
See Also
Session#lock(Object, LockMode)

Field Summary

Modifier and TypeField and Description
private final String
externalForm

public static final LockMode
FORCE

Similar to UPGRADE except that, for versioned entities, it results in a forced version increment.

private final int
level

public static final LockMode
NONE

No lock required.

public static final LockMode
OPTIMISTIC

Optimistically assume that transaction will not experience contention for entities.

public static final LockMode
OPTIMISTIC_FORCE_INCREMENT

Optimistically assume that transaction will not experience contention for entities.

public static final LockMode
PESSIMISTIC_FORCE_INCREMENT

Transaction will immediately increment the entity version.

public static final LockMode
PESSIMISTIC_READ

Implemented as PESSIMISTIC_WRITE.

public static final LockMode
PESSIMISTIC_WRITE

Transaction will obtain a database lock immediately.

public static final LockMode
READ

A shared lock.

public static final LockMode
UPGRADE

An upgrade lock.

public static final LockMode
UPGRADE_NOWAIT

Attempt to obtain an upgrade lock, using an Oracle-style select for update nowait.

public static final LockMode
UPGRADE_SKIPLOCKED

Attempt to obtain an upgrade lock, using an Oracle-style select for update skip locked.

public static final LockMode
WRITE

A WRITE lock is obtained when an object is updated or inserted.

Constructor Summary

AccessConstructor and Description
private
LockMode(int level, String externalForm)

Method Summary

Modifier and TypeMethod and Description
public static LockMode
fromExternalForm(String externalForm)

public boolean

Returns:

true if this lock mode is more restrictive than given lock mode
greaterThan(LockMode
LockMode to check
mode)

Check if this lock mode is more restrictive than the given lock mode.

public boolean

Returns:

true if this lock mode is less restrictive than given lock mode
lessThan(LockMode
LockMode to check
mode)

Check if this lock mode is less restrictive than the given lock mode.

public String
toExternalForm()

public static LockMode
valueOf(String name)

public static LockMode[]
values()

Inherited from java.lang.Enum:
clonecompareTodescribeConstableequalsfinalizegetDeclaringClasshashCodenameordinaltoStringvalueOf

Field Detail

externalFormback to summary
private final String externalForm
FORCEback to summary
public static final LockMode FORCE

Deprecated

instead use PESSIMISTIC_FORCE_INCREMENT

Similar to UPGRADE except that, for versioned entities, it results in a forced version increment.

Annotations
@Deprecated
levelback to summary
private final int level
NONEback to summary
public static final LockMode NONE

No lock required. If an object is requested with this lock mode, a READ lock will be obtained if it is necessary to actually read the state from the database, rather than pull it from a cache.

This is the "default" lock mode.

OPTIMISTICback to summary
public static final LockMode OPTIMISTIC

Optimistically assume that transaction will not experience contention for entities. The entity version will be verified near the transaction end.

OPTIMISTIC_FORCE_INCREMENTback to summary
public static final LockMode OPTIMISTIC_FORCE_INCREMENT

Optimistically assume that transaction will not experience contention for entities. The entity version will be verified and incremented near the transaction end.

PESSIMISTIC_FORCE_INCREMENTback to summary
public static final LockMode PESSIMISTIC_FORCE_INCREMENT

Transaction will immediately increment the entity version.

PESSIMISTIC_READback to summary
public static final LockMode PESSIMISTIC_READ

Implemented as PESSIMISTIC_WRITE. TODO: introduce separate support for PESSIMISTIC_READ

PESSIMISTIC_WRITEback to summary
public static final LockMode PESSIMISTIC_WRITE

Transaction will obtain a database lock immediately. TODO: add PESSIMISTIC_WRITE_NOWAIT

READback to summary
public static final LockMode READ

A shared lock. Objects in this lock mode were read from the database in the current transaction, rather than being pulled from a cache.

UPGRADEback to summary
public static final LockMode UPGRADE

Deprecated

instead use PESSIMISTIC_WRITE

An upgrade lock. Objects loaded in this lock mode are materialized using an SQL select ... for update.

Annotations
@Deprecated
UPGRADE_NOWAITback to summary
public static final LockMode UPGRADE_NOWAIT

Attempt to obtain an upgrade lock, using an Oracle-style select for update nowait. The semantics of this lock mode, once obtained, are the same as UPGRADE.

UPGRADE_SKIPLOCKEDback to summary
public static final LockMode UPGRADE_SKIPLOCKED

Attempt to obtain an upgrade lock, using an Oracle-style select for update skip locked. The semantics of this lock mode, once obtained, are the same as UPGRADE.

WRITEback to summary
public static final LockMode WRITE

A WRITE lock is obtained when an object is updated or inserted. This lock mode is for internal use only and is not a valid mode for load() or lock() (both of which throw exceptions if WRITE is specified).

Constructor Detail

LockModeback to summary
private LockMode(int level, String externalForm)

Method Detail

fromExternalFormback to summary
public static LockMode fromExternalForm(String externalForm)
greaterThanback to summary
public boolean greaterThan(LockMode mode)

Check if this lock mode is more restrictive than the given lock mode.

Parameters
mode:LockMode

LockMode to check

Returns:boolean

true if this lock mode is more restrictive than given lock mode

lessThanback to summary
public boolean lessThan(LockMode mode)

Check if this lock mode is less restrictive than the given lock mode.

Parameters
mode:LockMode

LockMode to check

Returns:boolean

true if this lock mode is less restrictive than given lock mode

toExternalFormback to summary
public String toExternalForm()
valueOfback to summary
public static LockMode valueOf(String name)
valuesback to summary
public static LockMode[] values()