oracle.jbo.server
Interface EntityListener

All Superinterfaces:

java.util.EventListener

All Known Implementing Classes:

CmrAccessorViewImpl, DCDataVO, DSViewObjectImpl, FinderViewImpl, PlaceholderVOImpl, ViewObjectImpl, ViewObjectOnRowSets

public interface EntityListener
extends java.util.EventListener

Implemented by classes that receive events generated by operations on Entity Object rows.

When an Entity Object's row data changes, listeners to row events are notified through a call to sourceChanged(). Listener's may be subscribed by calling addEntityListener().

Overview of Entity Object event flow.

When a new row is created through a call to createRow() on a View Object, rows are created for the Entity Object. After the rows are initialized, a STATE_CHANGE event is sent to listeners with a new post state of STATUS_NEW. As the user sets attributes on this row, ATTRIBUTE_CHANGE events are sent. After the new row is successfully posted to database, a STATE_CHANGE event is sent to listeners with a new post state of STATUS_UNMODIFIED. That is, after posting, the new row becomes an unmodified old row.

For an existing row, no Entity Object event is sent when the row is brought into the cache. However, when the user causes the row to be locked, an ATTRIBUTE_CHANGE event is sent with the attribute values present in the cache before locking. Locking may refresh rows, replacing their data with new data from the database. After the row is locked, the first call to setAttribute() will generate a STATE_CHANGE event with the new post state STATUS_MODIFIED. Subsequent calls to lock() and setAttribute() will generate ATTRIBUTE_CHANGE events. Note that if setAttribute() is called without first calling lock(), lock() will be called implicitly, and will generate an event of its own. These events may be distinguished by the fact that the Entity Object's post state when lock() generates its event is STATUS_UNMODIFIED, but is STATUS_MODIFIED for the event generated by setAttribute(). As in the case of a new row, after the modified row is successfully posted to database, a STATE_CHANGE event is generated with a new post state of STATUS_UNMODIFIED.

When a row is removed the row it is first locked, if it is not locked already, generating an ATTRIBUTE_CHANGE event as described above. Second, a BEFORE_REMOVE event is sent. Third, the row is marked as removed and a STATE_CHANGE event is sent with a new post status of STATUS_DELETED. Finally, another STATE_CHANGE event is sent with a new post status of STATUS_DEAD.

Since:

JDeveloper 3.0

See Also:

EntityListener, EntityEvent, EntityImpl, Entity

Method Summary

void	sourceChanged(EntityEvent event) Event handler called by an event publisher to report that an Entity Object's row data has changed.

Method Detail

sourceChanged

void sourceChanged(EntityEvent event)

Event handler called by an event publisher to report that an Entity Object's row data has changed.

Parameters:

event - the event describing the change.