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Class javax.infobus.DataItemChangeEvent

java.lang.Object
   |
   +----java.util.EventObject
           |
           +----javax.infobus.DataItemChangeEvent

public class DataItemChangeEvent
extends EventObject

A data item which implements the DataItemChangeManager interface propagates one of these events to all DataItemChangeListeners that have registered on its addDataItemChangeListener method whenever the data item's data has been modified. The event includes two fields:

source -- the DataItemChangeManager that fired the event
changedItem -- the data item that has changed.

If the source and changedItem fields are not equal, then the event conveys information about a change in a data item which is in a collection of data items or is itself such a collection.

Version:: $Revision: 1.8 $ $Date: 20 Feb 1998 16:50:02 $
See Also:: getChangedItem

getChangedItem(): Returns the DataItem that changed.
getProperty(String): Returns a property or metadata information about the change event.
getSource(): Returns the DataItem which sent the DataItemChangeEvent.

getSource

 public Object getSource()

Returns the DataItem which sent the DataItemChangeEvent. If the source is a collection, the getChangedItem may point to a unit in the collection that has changed.

Returns:: the sender of the DataItemChangeEvent
Overrides:: getSource in class EventObject

getChangedItem

 public Object getChangedItem()

Returns the DataItem that changed. May be the same as the object reported by getSource, or may be a subitem if getSource reports a collection

Returns:: the DataItem that has changed

getProperty

 public Object getProperty(String propertyName)

Returns a property or metadata information about the change event. For example, properties can provide information about the nature of sub-items that changed when getChangedItem() returns null (more than one sub-item changed).

Support for properties is optional. null will be returned for unsupported properties.

When this method is invoked, the DataItemChangeEvent in turn calls the get method for either the Map or InfoBusMap provided by the event constructor.

Parameters:: propertyName - the name of the property to be retrieved. Property names must not contain the ‘*’ character.
Returns:: the requested property, or null if the specified propertyName is not supported.

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