Package org.eclipse.emf.cdo.transaction

# Schnittstelle CDOTransactionHandler1

Alle Superschnittstellen:
  `CDOTransactionHandlerBase`

Alle bekannten Unterschnittstellen:
  `CDOTransactionHandler`, `CDOTransactionHandler1.WithUndo`

Alle bekannten Implementierungsklassen:
  `CDOAsyncTransactionHandler`, `CDOAutoAttacher`, `CDOAutoCommitter`, `CDOAutoLocker`, `CDOAutoLocker.ForSingleValuedChanges`, `CDODefaultTransactionHandler`, `CDODefaultTransactionHandler1`, `CDOPostEventTransactionHandler`, `CDOPostEventTransactionHandler.Default`

public interface CDOTransactionHandler1 extends CDOTransactionHandlerBase
A call-back interface that is called by a `transaction` before `objects` are attached, modified or detached.

Seit:
  4.0
Autor:
  Eike Stepper
Siehe auch:
  - `CDOPostEventTransactionHandler`

## Verschachtelte Klassen - Übersicht

Verschachtelte Klassen
Modifizierer und Typ
Schnittstelle
Beschreibung
`static interface`
`CDOTransactionHandler1.WithUndo`
A call-back interface that is called by a `transaction` before `objects` are attached, modified, undone or detached.

## Methodenübersicht

Modifizierer und Typ
Methode
Beschreibung
`void`
`attachingObject(CDOTransaction transaction, CDOObject object)`
Called by a `CDOTransaction` before an object is added.
`void`
`detachingObject(CDOTransaction transaction, CDOObject object)`
Called by a `CDOTransaction` before an object is detached.
`void`
`modifyingObject(CDOTransaction transaction, CDOObject object, CDOFeatureDelta featureDelta)`
Called by a `CDOTransaction` before an object is modified.

## Methodendetails

### attachingObject

void attachingObject(CDOTransaction transaction, CDOObject object)
Called by a `CDOTransaction` before an object is added. The implementor of this method is allowed to throw an unchecked exception that will propagate up to the operation that is about to add the object (thereby preventing the operation from successful completion).

Note: Implementors must not start threads which access the `view` and wait for their completion since deadlocks can result. The following example causes a deadlock:

     getDisplay().syncExec(new Runnable()
     {
       public void run()
       {
         try
         {
           cdoObject.getName();
         }
         catch (Exception ignore)
         {
         }
       }
     });

If you need to synchronously execute threads which access the `view` you should use `CDOAsyncTransactionHandler`.

### detachingObject

void detachingObject(CDOTransaction transaction, CDOObject object)
Called by a `CDOTransaction` before an object is detached. The implementor of this method is allowed to throw an unchecked exception that will propagate up to the operation that is about to remove the object (thereby preventing the operation from completing successfully).

Note: Implementors must not start threads which access the `view` and wait for their completion since deadlocks can result. The following example causes a deadlock:

     getDisplay().syncExec(new Runnable()
     {
       public void run()
       {
         try
         {
           cdoObject.getName();
         }
         catch (Exception ignore)
         {
         }
       }
     });

If you need to synchronously execute threads which access the `view` you should use `CDOAsyncTransactionHandler`.

### modifyingObject

void modifyingObject(CDOTransaction transaction, CDOObject object, CDOFeatureDelta featureDelta)
Called by a `CDOTransaction` before an object is modified. The implementor of this method is allowed to throw an unchecked exception that will propagate up to the operation that is about to modify the object (thereby preventing the operation from completing successfully).

Note: Implementors must not start threads which access the `view` and wait for their completion since deadlocks can result. The following example causes a deadlock:

     getDisplay().syncExec(new Runnable()
     {
       public void run()
       {
         try
         {
           cdoObject.getName();
         }
         catch (Exception ignore)
         {
         }
       }
     });

If you need to synchronously execute threads which access the `view` you should use `CDOAsyncTransactionHandler`.