org.hibernate
Class LockMode

java.lang.Object
  org.hibernate.LockMode

All Implemented Interfaces:

Serializable

public final class LockMode

extends Object

implements Serializable

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), Serialized Form

Field Summary

static LockMode	FORCE Similiar to UPGRADE except that, for versioned entities, it results in a forced version increment.
static LockMode	NONE No lock required.
static LockMode	READ A shared lock.
static LockMode	UPGRADE An upgrade lock.
static LockMode	UPGRADE_NOWAIT Attempt to obtain an upgrade lock, using an Oracle-style select for update nowait.
static LockMode	WRITE A WRITE lock is obtained when an object is updated or inserted.

Method Summary

boolean	greaterThan(LockMode mode) Check if this lock mode is more restrictive than the given lock mode.
boolean	lessThan(LockMode mode) Check if this lock mode is less restrictive than the given lock mode.
static LockMode	parse(String name)
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

NONE

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.

READ

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.

UPGRADE

public static final LockMode UPGRADE

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

UPGRADE_NOWAIT

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.

WRITE

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).

FORCE

public static final LockMode FORCE

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

Method Detail

toString

public String toString()

greaterThan

public boolean greaterThan(LockMode mode)

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

Parameters:

mode - LockMode to check

Returns:

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

lessThan

public boolean lessThan(LockMode mode)

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

Parameters:

mode - LockMode to check

Returns:

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

parse

public static LockMode parse(String name)