java.lang.Object
- java.lang.Enum<LockMode>
- - org.hibernate.LockMode

All Implemented Interfaces:

Serializable, Comparable<LockMode>
```
public enum LockMode
extends Enum<LockMode>
```
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.
This enumeration of lock modes competes with the JPA-defined LockModeType, but offers additional options, including UPGRADE_NOWAIT and UPGRADE_SKIPLOCKED.

See Also:

Session.lock(Object, LockMode), LockModeType, LockOptions, OptimisticLocking

Enum Constant Summary

Enum Constants
Enum Constant	Description
`NONE`	No lock required.
`OPTIMISTIC`	A shared optimistic lock.
`OPTIMISTIC_FORCE_INCREMENT`	A kind of exclusive optimistic lock.
`PESSIMISTIC_FORCE_INCREMENT`	A pessimistic write lock which immediately increments the version of the locked object.
`PESSIMISTIC_READ`	A pessimistic shared lock, which prevents concurrent transactions from writing the locked object.
`PESSIMISTIC_WRITE`	A pessimistic upgrade lock, which prevents concurrent transactions from reading or writing the locked object.
`READ`	A shared lock.
`UPGRADE_NOWAIT`	A pessimistic upgrade lock, obtained using an Oracle-style `select for update nowait`.
`UPGRADE_SKIPLOCKED`	A pessimistic upgrade lock, obtained using an Oracle-style `select for update skip locked`.
`WRITE`	An exclusive write lock.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`static LockMode`	`fromExternalForm(String externalForm)`
`static LockMode`	`fromJpaLockMode(LockModeType lockMode)`
`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.
`String`	`toExternalForm()`
`LockModeType`	`toJpaLockMode()`
`static LockModeType`	`toJpaLockMode(LockMode lockMode)`
`LockOptions`	`toLockOptions()`
`static LockMode`	`valueOf(String name)`	Returns the enum constant of this type with the specified name.
`static LockMode[]`	`values()`	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum
clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Enum Constant 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 turns out to be necessary to actually read the state from the database, rather than pull it from a cache.
    This is the "default" lock mode, the mode requested by calling Session.get(Class, Object) without passing an explicit mode. It permits the state of an object to be retrieved from the cache without the cost of database access.
    
    See Also:
    
    LockModeType.NONE
  - 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.
    Note that this lock mode is the same as the JPA-defined modes LockModeType.READ and LockModeType.OPTIMISTIC.
    
    See Also:
    
    LockModeType.OPTIMISTIC
  - OPTIMISTIC
```
public static final LockMode OPTIMISTIC
```
    A shared optimistic lock. Assumes that the current transaction will not experience contention for the state of an entity. The version will be checked near the end of the transaction, to verify that this was indeed the case.
    Note that, despite the similar names this lock mode is not the same as the JPA-defined mode LockModeType.OPTIMISTIC.
  - OPTIMISTIC_FORCE_INCREMENT
```
public static final LockMode OPTIMISTIC_FORCE_INCREMENT
```
    A kind of exclusive optimistic lock. Assumes that the current transaction will not experience contention for the state of an entity. The version will be checked and incremented near the end of the transaction, to verify that this was indeed the case, and to signal to concurrent optimistic readers that their optimistic locks have failed.
    
    See Also:
    
    LockModeType.OPTIMISTIC_FORCE_INCREMENT
  - WRITE
```
public static final LockMode WRITE
```
    An exclusive write lock. Objects in this lock mode were updated or inserted in the database in the current transaction.
    This lock mode is for internal use only and is not a legal argument to Session.get(Class, Object, LockMode), Session.refresh(Object, LockMode), or Session.lock(Object, LockMode). These methods throw an exception if WRITE is given as an argument.
    Note that, despite the similar names, this lock mode is not the same as the JPA-defined mode LockModeType.WRITE.
  - UPGRADE_NOWAIT
```
public static final LockMode UPGRADE_NOWAIT
```
    A pessimistic upgrade lock, obtained using an Oracle-style select for update nowait. The semantics of this lock mode, if the lock is successfully obtained, are the same as PESSIMISTIC_WRITE. If the lock is not immediately available, an exception occurs.
  - UPGRADE_SKIPLOCKED
```
public static final LockMode UPGRADE_SKIPLOCKED
```
    A pessimistic upgrade lock, obtained using an Oracle-style select for update skip locked. The semantics of this lock mode, if the lock is successfully obtained, are the same as PESSIMISTIC_WRITE. But if the lock is not immediately available, no exception occurs, but the locked row is not returned from the database.
  - PESSIMISTIC_READ
```
public static final LockMode PESSIMISTIC_READ
```
    A pessimistic shared lock, which prevents concurrent transactions from writing the locked object. Obtained via a select for share statement in dialects where this syntax is supported, and via select for update in other dialects.
    On databases which do not support for share, this lock mode is equivalent to PESSIMISTIC_WRITE.
    
    See Also:
    
    LockModeType.PESSIMISTIC_READ
  - PESSIMISTIC_WRITE
```
public static final LockMode PESSIMISTIC_WRITE
```
    A pessimistic upgrade lock, which prevents concurrent transactions from reading or writing the locked object. Obtained via a select for update statement.
    
    See Also:
    
    LockModeType.PESSIMISTIC_WRITE
  - PESSIMISTIC_FORCE_INCREMENT
```
public static final LockMode PESSIMISTIC_FORCE_INCREMENT
```
    A pessimistic write lock which immediately increments the version of the locked object. Obtained by immediate execution of an update statement.
    
    See Also:
    
    LockModeType.PESSIMISTIC_FORCE_INCREMENT
- Method Detail
  - values
```
public static LockMode[] values()
```
    Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:
    for (LockMode c : LockMode.values()) System.out.println(c);
    Returns:
    
    an array containing the constants of this enum type, in the order they are declared
  - valueOf
```
public static LockMode valueOf(String name)
```
    Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
    
    Parameters:
    
    name - the name of the enum constant to be returned.
    
    Returns:
    
    the enum constant with the specified name
    
    Throws:
    
    IllegalArgumentException - if this enum type has no constant with the specified name
    
    NullPointerException - if the argument is null
  - fromJpaLockMode
```
public static LockMode fromJpaLockMode(LockModeType lockMode)
```
  - toJpaLockMode
```
public static LockModeType toJpaLockMode(LockMode lockMode)
```
  - toJpaLockMode
```
public LockModeType toJpaLockMode()
```
  - 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
  - toExternalForm
```
public String toExternalForm()
```
  - fromExternalForm
```
public static LockMode fromExternalForm(String externalForm)
```
  - toLockOptions
```
public LockOptions toLockOptions()
```
    Returns:
    
    an instance of LockOptions with this lock mode, and all other settings defaulted.

Enum LockMode

Enum Constant Summary

Method Summary

Methods inherited from class java.lang.Enum

Methods inherited from class java.lang.Object

Enum Constant Detail

NONE

READ

OPTIMISTIC

OPTIMISTIC_FORCE_INCREMENT

WRITE

UPGRADE_NOWAIT

UPGRADE_SKIPLOCKED

PESSIMISTIC_READ

PESSIMISTIC_WRITE

PESSIMISTIC_FORCE_INCREMENT

Method Detail

values

valueOf

fromJpaLockMode

toJpaLockMode

toJpaLockMode

greaterThan

lessThan

toExternalForm

fromExternalForm

toLockOptions