Functional Item events related to Device Items

For receiving the events related to the Device Items, there should have any available Devices in the system, that have defined functionality (Device Items). You can learn more about how to create a Device with DeviceItem from the Creating a Device guide.

Subscribing to Events When Device Item Properties are Changed

The FunctionalItemEventConstnats.TOPIC_PROPERTY_CHANGED is thrown when:

• Device Item registration properties are changed - FunctionalItem.NAME and FunctionalItem.TAGS
• The functional properties, defined by FunctionalItem interface. These properties should be specified as eventable in the metadata. Each FunctionalItem interface that has eventable properties should publish an events on each eventable property value change.

The properties of this event are:

• FunctionalItemEventConstants.PROPERTY_NAME
• FunctionalItemEventConstants.PROPERTY_NEW_VALUE
• FunctionalItemEventConstants.PROPERTY_OLD_VALUE
• FunctionalItem.UID
• FunctionalItem.NAME
• FunctionalItem.TAGS
• FunctionalItem.OBJECT_CLASS
• EventConstants.TIMESTAMP
• all additional registration properties, defined in FunctionalItem.getAttributes()

Subscribing to Events When FunctionalItem.NAME Property Changed

The following example demonstrate how to subscribe for FunctionalItemEventConstants.TOPIC_PROPERTY_CHANGED, when Device Item with UID test:device:item:UID changes its property FunctionalItem.NAME. For example to receive this event, you have to call FunctionalItem.setName(String) on this Device Item.

public void registerListener() {

  Hashtable<String, String> properties = new Hashtable<String, String>();

  properties.put(EventConstants.EVENT_TOPIC, FunctionalItemEventConstants.TOPIC_PROPERTY_CHANGED);

  properties.put(EventConstants.EVENT_FILTER, "(&(" + FunctionalItem.UID + "=test:device:item:UID)(" + FunctionalItemEventConstants.PROPERTY_NAME + '=' + FunctionalItem.NAME + "))");

  serviceRegistration = bc.registerService(EventHandler.class, this, properties);

}

Subscribing to Events When FunctionalItem.TAGS Property Changed

The following example demonstrate how to subscribe for FunctionalItemEventConstants.TOPIC_PROPERTY_CHANGED, when Device Item with UID test:device:item:UID change its property FunctionalItem.TAGS. For example to receive this event, you have to call FunctionalItem.setTags(Set<String>) on this Device Item.

public void registerListener() {

  Hashtable<String, String> properties = new Hashtable<String, String>();

  properties.put(EventConstants.EVENT_TOPIC, FunctionalItemEventConstants.TOPIC_PROPERTY_CHANGED);

  properties.put(EventConstants.EVENT_FILTER, "(&(" + FunctionalItem.UID + "=test:device:item:UID)(" + FunctionalItemEventConstants.PROPERTY_NAME + '=' + FunctionalItem.TAGS + "))");

  serviceRegistration = bc.registerService(EventHandler.class, this, properties);

}

Subscribing to Events When eventable Property Changed

The following example demonstrate how to subscribe for FunctionalItemEventConstants.TOPIC_PROPERTY_CHANGED, when Device Items with object class StepperMotor change the property StepperMotor.PROPERTY_DIRECTION. For example to receive this event, you have to call StepperMotor.setDirection(String) on this Device Item.

public void registerListener() {

  Hashtable<String, String> properties = new Hashtable<String, String>();

  properties.put(EventConstants.EVENT_TOPIC, FunctionalItemEventConstants.TOPIC_PROPERTY_CHANGED);

  properties.put(EventConstants.EVENT_FILTER, "(&(" + FunctionalItem.OBJECT_CLASS + '=' + StepperMotor.class.getName() + ")("

                                                    + FunctionalItemEventConstants.PROPERTY_NAME + '=' + StepperMotor.PROPERTY_DIRECTION + "))");

  serviceRegistration = bc.registerService(EventHandler.class, this, properties);

}

FunctionalItemEventConstants.TOPIC_OPERATION_EXECUTED

FunctionalItem event with topic FunctionalItemEventConstants.TOPIC_OPERATION_EXECUTED is not created for all operations in Device Access, exept for the operations in Device Admin:

• DeviceAdmin.OPERATION_CREATE, DeviceAdmin.OPERATION_CREATE_DEVICE, DeviceAdmin.OPERATION_REMOVE and
• DeviceAdmin.OPERATION_REMOVE_DEVICE.