T find(
Class<T> entityClass,
Object primaryKey,
LockModeType lockMode
)
Find by primary key and lock. Search for an entity of the specified class and primary key and lock it with respect to the specified lock type. If the entity instance is contained in the persistence context, it is returned from there, and the effect of this method is the same as if the lock method had been called on the entity.
If the entity is found within the persistence context and the lock mode type is pessimistic and the entity has a version attribute, the persistence provider must perform optimistic version checks when obtaining the database lock. If these checks fail, the OptimisticLockException will be thrown.
If the lock mode type is pessimistic and the entity instance is found but cannot be locked:
- the
PessimisticLockExceptionwill be thrown if the database locking failure causes transaction-level rollback - the
LockTimeoutExceptionwill be thrown if the database locking failure causes only statement-level rollback
- Parameters:
entityClass- entity classprimaryKey- primary keylockMode- lock mode
- Return:
- the found entity instance or null if the entity does not exist
- Throws:
- IllegalArgumentException - if the first argument does not denote an entity type or the second argument is not a valid type for that entity's primary key or is null
- TransactionRequiredException - if there is no transaction and a lock mode other than
NONEis specified or if invoked on an entity manager which has not been joined to the current transaction and a lock mode other thanNONEis specified- OptimisticLockException - if the optimistic version check fails
- PessimisticLockException - if pessimistic locking fails and the transaction is rolled back
- LockTimeoutException - if pessimistic locking fails and only the statement is rolled back
- PersistenceException - if an unsupported lock call is made
- TransactionRequiredException - if there is no transaction and a lock mode other than
- Since:
- JPA 2.0