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Interface javax.infobus.InfoBusDataConsumer

public interface InfoBusDataConsumer

extends InfoBusEventListener

An InfoBusDataConsumer must track the InfoBus property of the InfoBusMember that obtained the bus for them, so that if the setInfoBus method is called with a new InfoBus, the producer will know to register with the new bus and deregister with the old. This is the only bound property that the InfoBus protocol requires InfoBusDataConsumers to track. The base interface, InfoBusEventListener, extends java.beans.PropertyChangeListener to accomplish this, which in turn requires InfoBusDataConsumers to implement a propertyChange() method.

Version:

$Revision: 1.8 $ $Date: 24 Feb 1998 17:04:32 $

dataItemAvailable(InfoBusItemAvailableEvent)

This method is called by the InfoBus class on behalf of a data producer that is announcing the availability of a new data item by name.

dataItemRevoked(InfoBusItemRevokedEvent)

This method is called by the InfoBus class on behalf of a data producer that is revoking the availability of a previously announced data item.

 public abstract void dataItemAvailable(InfoBusItemAvailableEvent event)

This method is called by the InfoBus class on behalf of a data producer that is announcing the availability of a new data item by name. A consumer that obtains a DataItem from a producer should be prepared to release it when the producer announces that the item is being revoked via InfoBusDataConsumer.dataItemRevoked().

The suggested implementation of dataItemAvailable:

• Check the data item name (obtained via event.getDataItemName()) to see if the item is wanted. If not, return.
• Get a reference to the DataItem by calling the findDataItem() method on the InfoBus instance this consumer has joined, passing event.getSource() as the argument for the producer and this for the consumer.
• If desired, set a DataItemChangeListener on the DataItem.

Parameters:

event - the InfoBus event for the availability of the data item

 public abstract void dataItemRevoked(InfoBusItemRevokedEvent event)

This method is called by the InfoBus class on behalf of a data producer that is revoking the availability of a previously announced data item. A consumer that is using this data item should release it upon receiving this notification.

The suggested implementation of dataItemRevoked:

• check the data item name (obtained via event.getDataItemName()) to see if this is an item held by this consumer. If not, return.
• remove any change listeners set on this DataItem.
• release all references to the DataItem held by this consumer.

Parameters:

event - the InfoBus event for the revocation of the data item

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