org.apache.jdo.ejb
Interface EJBHelper


public interface EJBHelper

Provide a Forte for Java implementation with information about the distributed transaction environment. This is an interface that a helper class implements that is specific to a managed environment.

This interface is specific to Forte for Java, version 3.0, and is subject to change without notice. In particular, as additional experience is gained with specific application servers, this interface may have methods added and removed, even with patch releases. Therefore, this interface should be considered very volatile, and any class that implements it might have to be reimplemented whenever an upgrade to either the application server or Forte for Java occurs.

The class that implements this interface must register itself by a static method at class initialization time. For example,
 import org.apache.jdo.*;
 class blackHerringEJBImplHelper implements EJBHelper {
    static EJBHelper.register(new blackHerringEJBImplHelper());
    ...
 }
 

Author:
Marina Vatkina

Method Summary
 void delistBeforeCompletion(java.lang.Object im)
          Called at the end of the Transaction.beforeCompletion() to de-register the component with the app server if necessary.
 java.lang.Object enlistBeforeCompletion(java.lang.Object component)
          Called at the beginning of the Transaction.beforeCompletion() to register the component with the app server if necessary.
 javax.transaction.Transaction getTransaction()
          Identify the Transaction context for the calling thread, and return a Transaction instance that can be used to register synchronizations, and used as the key for HashMaps.
 javax.transaction.UserTransaction getUserTransaction()
          Returns the UserTransaction associated with the calling thread.
 javax.jdo.PersistenceManagerFactory replacePersistenceManagerFactory(javax.jdo.PersistenceManagerFactory pmf)
          Replace newly created instance of internal PersistenceManagerFactory with the hashed one if it exists.
 int translateStatus(int st)
          Translate local representation of the Transaction Status to javax.transaction.Status value if necessary.
 

Method Detail

getUserTransaction

javax.transaction.UserTransaction getUserTransaction()
Returns the UserTransaction associated with the calling thread. If there is no transaction currently in progress, this method returns null.

Returns:
the UserTransaction instance for the calling thread

getTransaction

javax.transaction.Transaction getTransaction()
Identify the Transaction context for the calling thread, and return a Transaction instance that can be used to register synchronizations, and used as the key for HashMaps. The returned Transaction must implement equals() and hashCode() based on the global transaction id.

All Transaction instances returned by this method called in the same Transaction context must compare equal and return the same hashCode. The Transaction instance returned will be held as the key to an internal HashMap until the Transaction completes. If there is no transaction associated with the current thread, this method returns null.

Returns:
the Transaction instance for the calling thread

translateStatus

int translateStatus(int st)
Translate local representation of the Transaction Status to javax.transaction.Status value if necessary. Otherwise this method should return the value passed to it as an argument.

This method is used during afterCompletion callbacks to translate the parameter value passed by the application server to the afterCompletion method. The return value must be one of: javax.transaction.Status.STATUS_COMMITTED or javax.transaction.Status.STATUS_ROLLED_BACK.

Parameters:
st - local Status value
Returns:
the javax.transaction.Status value of the status

replacePersistenceManagerFactory

javax.jdo.PersistenceManagerFactory replacePersistenceManagerFactory(javax.jdo.PersistenceManagerFactory pmf)
Replace newly created instance of internal PersistenceManagerFactory with the hashed one if it exists. The replacement is necessary only if the JNDI lookup always returns a new instance. Otherwise this method returns the object passed to it as an argument. PersistenceManagerFactory is uniquely identified by ConnectionFactory.hashCode() if ConnectionFactory is not null; otherwise by ConnectionFactoryName.hashCode() if ConnectionFactoryName is not null; otherwise by the combination of URL.hashCode() + userName.hashCode() + password.hashCode() + driverName.hashCode();

Parameters:
pmf - PersistenceManagerFactory instance to be replaced
Returns:
the PersistenceManagerFactory known to the runtime

enlistBeforeCompletion

java.lang.Object enlistBeforeCompletion(java.lang.Object component)
Called at the beginning of the Transaction.beforeCompletion() to register the component with the app server if necessary. The component argument is an array of Objects. The first element is javax.jdo.Transaction object responsible for transaction completion. The second element is javax.jdo.PersistenceManager object that has been associated with the Transaction context for the calling thread. The third element is javax.transaction.Transaction object that has been associated with the given instance of PersistenceManager. The return value is passed unchanged to the postInvoke method.

Parameters:
component - an array of Objects
Returns:
implementation-specific Object

delistBeforeCompletion

void delistBeforeCompletion(java.lang.Object im)
Called at the end of the Transaction.beforeCompletion() to de-register the component with the app server if necessary. The parameter is the return value from preInvoke, and can be any Object.

Parameters:
im - implementation-specific Object


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