About find

manual

Retrieving JPA Entity Objects

Explains how to use JPA to retrieve entity objects from the database.... primary key is 1: Employee employee = em. find find(entityClass, primaryKey) EntityManager's method Find by ...

 
api-jpa

find(entityClass, primaryKey)

Find by primary key.(Method of javax.persistence.EntityManager)

 
api-jpa

find(entityClass, primaryKey, properties)

Find by primary key, using the specified properties.(Method of javax.persistence.EntityManager)

 
manual

Locking in JPA

Explains how to use optimistic locking and pessimistic locking in JPA.... methods that take locks (lock, find, or refresh) or to the Query.setLockMode() or TypedQuery.setLockMode() ... methods that take locks (lock, find, or refresh) or to the Query.setLockMode() or TypedQuery.setLockMode() ... as one atomic operation. For example, the find find(entityClass, primaryKey, lockMode) EntityManager's ...

 
manual

CRUD Operations with JPA

Explains how to use JPA for CRUD database operations (persist, retrieve, update, remove). The following subsections explain how to use JPA for CRUD database operations: Storing JPA Entity Objects Retrieving JPA Entity Objects Updating JPA Entity Objects Deleting JPA Entity Objects ...

 
forum_thread

find() cost unreasonable time!

Hi, I make a full binary tree of 4095 node, I check the first 9 node, but the root cost 24 seconds, why? Result: ... 24 seconds, why? Result: =========== find time @ 24.125000 getSons time @ 0.000000 1 : ... 2 child : 3 Iterator time @ 0.000000 find time @ 0.000000 getSons time @ 0.000000 2 : type ...

 
api-jpa

find(entityClass, primaryKey, lockMode)

Find by primary key and lock.(Method of javax.persistence.EntityManager)

 
forum_thread

What algorithm in find()

I test the time cost for find(), obtain a linear complexity with the following codes: ... I test the time cost for find(), obtain a linear complexity with the following codes: int ... new Node ( ) ; Node p = em. find ( Node. class , i / 3 ) ; if ( ...

 
forum_thread

find() delay

Hi, I tried objectdb in following steps: 1, for 1 to 30 {trans.begin(); create typeC o; em.persist(o); trans.commit();} 2, for 1 to 30 {p = em.find(typeC.class, i); print(p)} So simple a test, there is no result in one go; I have to disable step 1 and run again, then Step 2 output the expected results. I tried em.flush(), em.clear(), etc.. that do not work. Any idea? TIA ... trans.commit();} 2, for 1 to 30 {p = em.find(typeC.class, i); print(p)} So simple a test, there is no result in ... L2 cache? I'm not sure. But why the second find() will output? By the way, a query "select e from nodes e" will be ...

 
issue

Blocked by find

I have a container object which wraps an objectdb database. There is a "putIfAbsent(String id, Object obj)" method which is synchronized and attempts to load an object by id using the EntityManager "find" method. If nothing is returned from the db the passed object is persisted to the db. I have 5 threads which use this method. In a run today one of the threads seems to have got stuck somewhere in the find. The thread dump looks like: ... attempts to load an object by id using the EntityManager "find" method. If nothing is returned from the db the passed object is persisted ... of the threads seems to have got stuck somewhere in the find. The thread dump looks like: Name: DEV1-WSAgent-1-Existing/3 State: ...