Nested Class Summary

Enum Constant Summary

Enum Constants

Method Summary

Enum Constant Details

• 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.find(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, despite the similar names this lock mode is not the same as the JPA-defined mode LockModeType.READ.

• 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.

  Only legal for versioned entity types.

  Note that this lock mode is the same as the JPA-defined modes LockModeType.READ and LockModeType.OPTIMISTIC.

  See Also:

  • 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.

  Only legal for versioned entity types.

  See Also:

  • LockModeType.OPTIMISTIC_FORCE_INCREMENT

• WRITE

• 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.

  Only legal for versioned entity types.

  See Also:

  • LockModeType.PESSIMISTIC_FORCE_INCREMENT

• 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.

  API Note:

  To be removed in a future version. A different approach to specifying handling for locked rows will be introduced.

• 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.

  API Note:

  To be removed in a future version. A different approach to specifying handling for locked rows will be introduced.

Method Details

• values

  public static LockMode[] values()

  Returns an array containing the constants of this enum class, in the order they are declared.

  Returns:

  an array containing the constants of this enum class, in the order they are declared

• valueOf

  Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (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 class has no constant with the specified name

  NullPointerException - if the argument is null

• fromJpaLockMode

  Returns:

  an instance with the same semantics as the given JPA LockModeType.

• toJpaLockMode

  Returns:

  an instance of the JPA-defined LockModeType with similar semantics to the given LockMode.

• toJpaLockMode

  Returns:

  an instance of the JPA-defined LockModeType with similar semantics to this LockMode.

• 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

• requiresVersion

  public boolean requiresVersion()

  Does this lock mode require a version?

  Returns:

  true if this lock mode only applies to versioned entities

• toExternalForm

  public String toExternalForm()

• fromExternalForm

  public static LockMode fromExternalForm (String externalForm)

• toLockOptions

  Deprecated, for removal: This API element is subject to removal in a future version.

  Returns:

  an instance of LockOptions with this lock mode, and all other settings defaulted.