View Object States and Events

The Business Components for Java framework follows the standard Java/EJB event delegation model for propagating events among middle-tier objects. Publishers (also called senders) fire events, subscribers (also called listeners) respond to them.

Java event types are classes that extend java.util.EventObject. The framework sends an event from a publisher to a subscriber by invoking a method of the RowSetListener interface on the subscriber and passing in an instance of the event type generated. The subscriber registers listeners by using addEventTypeListener() on the publisher.

The publisher defines the set of events it emits by providing addEventTypeListener methods which register specific listeners for those events.

A subscriber implements a specific EventListener interface, RowSetListener, that extends java.util.EventListener. An EventListener interface defines one or more methods to invoke in response to each specific event type handled by the interface.

The following Business Components for Java classes for built-in events can be found in the oracle.jbo package. They can be published by various Business Components and are used to manage three-tier communications.

Event Class

Description

JboEvent

Extends java.util.EventObject. All Business Component events subclass this class.

NavigationEvent

Fired when the iterator position in a View Object changes. It provides the following methods:

getPreviousRow

getPreviousRowIndex

getNextRow

getNextRowIndex

toString

RangeEvent

Base class for range oriented event. RangeRefreshEvent, and ScrollEvent subclass this class.

RangeRefreshEvent

Fired when the range is refreshed, not when a row is updated--use UpdateEvent for that. In addition to RangeEvent methods, it has the following methods:

getAllRowsInRange

getRangeStart

getRowCountInRange

toString

ScrollEvent

Fired when the range is scrolled. In addition to RangeEvent methods, it has the following methods:

getRangeStartBefore

getScrollAmount

getFirstNewRowRangeIndex

getNewRowCountInRange

RowEvent

RowEvent is the base class for other row-oriented events. It has the following methods:

getRow

getRowIndex

InsertDeleteEvent

Used for insert or delete event. In addition to RowEvent methods, it has the following methods:

getRowCountInRangeBefore

getRowCountInRange

Note: getRowIndex returns the absolute row index, not range-relative.

InsertEvent

Provides a toString method.

DeleteEvent

Provides a toString method.

UpdateEvent

Adds the following methods:

getChangedAttrIndices

getChangedAttrNames

Event Class	Description
`JboEvent`	Extends `java.util.EventObject.` All Business Component events subclass this class.
`NavigationEvent`	Fired when the iterator position in a View Object changes. It provides the following methods: `getPreviousRow` `getPreviousRowIndex` `getNextRow` `getNextRowIndex` `toString`
`RangeEvent`	Base class for range oriented event. `RangeRefreshEvent`, and `ScrollEvent` subclass this class.
`RangeRefreshEvent`	Fired when the range is refreshed, not when a row is updated--use `UpdateEvent` for that. In addition to `RangeEvent` methods, it has the following methods: `getAllRowsInRange` `getRangeStart` `getRowCountInRange` `toString`
`ScrollEvent`	Fired when the range is scrolled. In addition to `RangeEvent` methods, it has the following methods: `getRangeStartBefore` `getScrollAmount` `getFirstNewRowRangeIndex` `getNewRowCountInRange`
`RowEvent`	`RowEvent` is the base class for other row-oriented events. It has the following methods: `getRow` `getRowIndex`
`InsertDeleteEvent`	Used for insert or delete event. In addition to `RowEvent` methods, it has the following methods: `getRowCountInRangeBefore` `getRowCountInRange` Note: `getRowIndex` returns the absolute row index, not range-relative.
`InsertEvent`	Provides a `toString` method.
`DeleteEvent`	Provides a `toString` method.
`UpdateEvent`	Adds the following methods: `getChangedAttrIndices` `getChangedAttrNames`