HibernateTxFragment (Dashboard Builder Commons 6.0.0.Beta3 API)

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org.jboss.dashboard.database.hibernate
Class HibernateTxFragment

java.lang.Object
  org.jboss.dashboard.database.hibernate.HibernateTxFragment

public abstract class HibernateTxFragment
extends Object
extends Object

A transaction fragment is a block of code executed inside the scope of a global transaction.

Pattern:

 // Define the transaction fragment
 final String finalVar = "";
 new HibernateTxFragment() {
 new HibernateTxFragment(false, true) { // Activate callback methods afterXXX/beforeXXX.
 new HibernateTxFragment(true, false) { // Open a brand new transaction.
 protected void txFragment(Session session) throws Exception {
   // Transactional block
   // ...
   finalVar = ""; // Forbidden sentence
 }}.execute();

IMPORTANT NOTE: All variables accessed inside the transaction fragment block must be defined as final because a inner class can't change the reference to a variable defined into its scope.

Another issue to be considered is what happens when a fragment needs to return a value from txFragment method. Use an array or collection to store the return value(s):

 final Object[] result = new Object[] {null};
 new HibernateTxFragment() {
 protected void txFragment(Session session) throws Exception {
    // ...
    result[0] = ...;
 }}.execute();
 return result[0];

The variable result can be an array or a collection or any other structure where we can store the results to be returned by the fragment block.

Field Summary
`protected boolean`	`callbacksEnabled` If true then this fragment will receive callback invocations both before and after the transaction completion.
`protected boolean`	`flushAfterFinish` Flag to control the Hibernate flush.
`protected boolean`	`newTransactionRequested` Flag to control the reuse of the current transaction.
`protected HibernateTxFragment`	`parentFragment` The parent fragment.

Constructor Summary
`HibernateTxFragment()` Create a new fragment linked to existing transaction if any
`HibernateTxFragment(boolean newTransactionRequested)` Create a new fragment
`HibernateTxFragment(boolean newTransactionRequested, boolean callbacksEnabled)` Create a new fragment
`HibernateTxFragment(boolean newTransactionRequested, boolean callbacksEnabled, boolean flushAfterFinish)` Create a new fragment

Method Summary
`protected void`	`afterCommit()` Callback method invoked after a transaction rollback.
`protected void`	`afterRollback()` Callback method invoked after a transaction commit.
`protected void`	`beforeCommit()` Callback method invoked before the transaction is commited.
`protected void`	`beforeRollback()` Callback method invoked before the transaction is rolled back.
`void`	`execute()` Execute this fragment.
`protected void`	`executeChild(HibernateTransaction tx)`
`protected void`	`executeInitiator(HibernateTransaction tx)`
`protected void`	`markAsRollbackOnly()` Mark the transaction as rollback only
`protected void`	`markAsRollbackOnly(Throwable t)` Mark the transaction as rollback only
`protected void`	`registerForCallbackNotifications()` Enable callback method notifications: `beforeCommit, afterCommit` will be invoked if the transaction is commited and `beforeRollback, afterRollback` otherwise.
`protected void`	`txFragment(org.hibernate.Session session)` Custom fragment implementation.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

newTransactionRequested

protected boolean newTransactionRequested

Flag to control the reuse of the current transaction. If true then a brand new transaction is opened and added to the list of transactions linked with the current thread.

flushAfterFinish

protected boolean flushAfterFinish

Flag to control the Hibernate flush. If true a Session.flush() call will be performed just before the finish of the tx fragment.

callbacksEnabled

protected boolean callbacksEnabled

If true then this fragment will receive callback invocations both before and after the transaction completion.

parentFragment

protected HibernateTxFragment parentFragment

The parent fragment. It only applies for child fragments.

Constructor Detail