org.needle4j.db.transaction

Class TransactionHelper

java.lang.Object

org.needle4j.db.transaction.TransactionHelper

public class TransactionHelper
extends Object

Utility class to manage transactions conveniently.

Constructor Summary

Constructors

Constructor and Description
TransactionHelper(javax.persistence.EntityManager manager)

Method Summary

Methods

Modifier and Type	Method and Description
<T> T	executeInTransaction(Runnable<T> runnable) see executeInTransaction(runnable, clearAfterCommit) .
<T> T	executeInTransaction(Runnable<T> runnable, boolean clearAfterCommit) Encapsulates execution of runnable.run() in transactions.
javax.persistence.EntityManager	getEntityManager()
<T> List<T>	loadAllObjects(Class<T> clazz) Returns all objects of the given class in persistence context.
<T> T	loadObject(Class<T> clazz, Object id) Finds and returns the object of the given id in the persistence context.
<T> T	loadObject(javax.persistence.EntityManager entityManager, Class<T> clazz, Object id)
<T> T	persist(T obj)
<T> T	persist(T obj, javax.persistence.EntityManager entityManager)
<T> T	saveObject(T obj) Saves the given object in the database.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TransactionHelper

public TransactionHelper(javax.persistence.EntityManager manager)

Method Detail

saveObject

public final <T> T saveObject(T obj)
                   throws Exception

Saves the given object in the database.

Type Parameters:

T - type of given object obj

Parameters:

obj - object to save

Returns:

saved object

Throws:

Exception - save objects failed

loadObject

public final <T> T loadObject(Class<T> clazz,
               Object id)
                   throws Exception

Finds and returns the object of the given id in the persistence context.

Type Parameters:

T - type of searched object

Parameters:

clazz - type of searched object

id - technical id of searched object

Returns:

found object

Throws:

Exception - finding object failed

loadAllObjects

public final <T> List<T> loadAllObjects(Class<T> clazz)
                             throws Exception

Returns all objects of the given class in persistence context.

Type Parameters:

T - type of searched objects

Parameters:

clazz - type of searched objects

Returns:

list of found objects

Throws:

IllegalArgumentException - if the instance is not an entity

Exception - selecting objects failed

executeInTransaction

public final <T> T executeInTransaction(Runnable<T> runnable,
                         boolean clearAfterCommit)
                             throws Exception

Encapsulates execution of runnable.run() in transactions.

Type Parameters:

T - result type of runnable.run()

Parameters:

runnable - algorithm to execute

clearAfterCommit - true triggers entityManager.clear() after transaction commit

Returns:

return value of runnable.run()

Throws:

Exception - execution failed

executeInTransaction

public final <T> T executeInTransaction(Runnable<T> runnable)
                             throws Exception

see executeInTransaction(runnable, clearAfterCommit) .

Type Parameters:

T - result type of runnable.run()

Parameters:

runnable - algorithm to execute

Returns:

return value of runnable.run()

Throws:

Exception - execution failed

getEntityManager

public final javax.persistence.EntityManager getEntityManager()

persist

public <T> T persist(T obj,
            javax.persistence.EntityManager entityManager)

persist

public <T> T persist(T obj)

loadObject

public <T> T loadObject(javax.persistence.EntityManager entityManager,
               Class<T> clazz,
               Object id)