info.pppc.base.system

Class DeviceRegistry

java.lang.Object

info.pppc.base.system.DeviceRegistry

All Implemented Interfaces:

IOperation

public final class DeviceRegistry
extends java.lang.Object
implements IOperation

This class implements a local registry for locally available plug-ins and their descriptions. Remotely available plug-in descriptions are tracked as well. A new description which references an unknown system causes a notification of all listeners. Descriptions which have not been updated for a while are removed. All listeners are notified about this event. The methods of the device registry are synchronized additional synchronization for single methods is not required.

Author:

Marcus Handte

Field Summary

Fields

Modifier and Type	Field and Description
static int	EVENT_DEVICE_ADDED The event constant used to signal that a remote device has been added.
static int	EVENT_DEVICE_REMOVED The event constant used to signal that a remote device has been removed.

Method Summary

Methods

Modifier and Type	Method and Description
void	addDeviceListener(int type, IListener listener) Adds a device listener to this device registry.
boolean	containsDevice(SystemID id) Determines whether the specified device is currently contained in the set of devices.
DeviceDescription	getDeviceDescription(SystemID id) Returns the device description of the system with the specified id.
SystemID[]	getDevices() Returns an array of system id that has been discovered recently.
SystemID[]	getDevices(ObjectID oid) Returns an array of system ids that have been discovered recently and that contain the specified well known service.
SystemID[]	getDevices(ObjectID[] ids) Returns an array of system ids that consists of systems that contain the specified well known services.
PluginDescription[]	getPluginDescriptions(SystemID systemID) Returns a set of plug-in descriptions which have been registered for a given system.
PluginDescription[]	getPluginDescriptions(SystemID source, SystemID target) Returns the plug-in descriptions of the target system that are compatible with the source system.
SystemID[]	getRemoteDevices() Returns an array of remote system id that has been discovered recently.
SystemID[]	getRemoteDevices(ObjectID oid) Returns an array of remote system ids that have been discovered recently and that contain the specified well known service.
SystemID[]	getRemoteDevices(ObjectID[] ids) Returns an array of remote system ids that consists of systems that contain the specified well known services.
void	perform(IMonitor monitor) This operation continuously removes the devices and plug-ins from the registry whose ttl has been run out.
void	registerDevice(DeviceDescription device) Registers the specified device description.
void	registerDevice(DeviceDescription device, long ttl) Registers a device description that has been discovered from a remote device.
void	registerPlugin(SystemID id, PluginDescription plugin) Registers the specified plug-in description of the specified device.
void	registerPlugin(SystemID id, PluginDescription plugin, long ttl) Registers the specified plug-in description of the specified device.
void	removeDevice(SystemID id) Removes the device description of the specified system from the list of permanently registered device descriptions.
boolean	removeDeviceListener(int type, IListener listener) Removes a device listener from this registry.
void	removePlugin(SystemID id, PluginDescription plugin) Removes the specified plug-in from the set of permanently registered plug-ins.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EVENT_DEVICE_ADDED

public static final int EVENT_DEVICE_ADDED

The event constant used to signal that a remote device has been added. The user object of the event will be the device description of the remote device.

See Also:

Constant Field Values

EVENT_DEVICE_REMOVED

public static final int EVENT_DEVICE_REMOVED

The event constant used to signal that a remote device has been removed. The user object of the event will be the device description of the remote device.

See Also:

Constant Field Values

Method Detail

addDeviceListener

public void addDeviceListener(int type,
                     IListener listener)

Adds a device listener to this device registry. The device listener keeps track of changes to devices that are registered at this registry. The supported events are EVENT_DEVICE_ADDED and EVENT_DEVICE_REMOVED. These events are fired whenever a device is added or removed.

Parameters:

type - The types of events to register. Multiple types can be added by concatenation.

listener - The listener to register.

removeDeviceListener

public boolean removeDeviceListener(int type,
                           IListener listener)

Removes a device listener from this registry. If the device listener has been removed completely, this method will return true, otherwise false.

Parameters:

type - The types of events to unregister.

listener - The listener to unregister.

Returns:

True if the listener has been removed, false otherwise.

registerDevice

public void registerDevice(DeviceDescription device,
                  long ttl)

Registers a device description that has been discovered from a remote device. A call to this method will replace a potentially previously registered description with the new one provided by the call. The device description stays registered as long as the ttl has not run out.

Parameters:

device - The device description of the device that announced the descriptions.

ttl - The time to live.

registerDevice

public void registerDevice(DeviceDescription device)

Registers the specified device description. If the description has been registered before, the device description is overwritten. The device stays registered until the remove method is called.

Parameters:

device - The device description to register.

removeDevice

public void removeDevice(SystemID id)

Removes the device description of the specified system from the list of permanently registered device descriptions.

Parameters:

id - The id of the device to remove.

containsDevice

public boolean containsDevice(SystemID id)

Determines whether the specified device is currently contained in the set of devices.

Parameters:

id - The system id of the device to lookup.

Returns:

True if the device is contained in the registry, false otherwise.

getDevices

public SystemID[] getDevices()

Returns an array of system id that has been discovered recently.

Returns:

The devices that have been discovered.

getDevices

public SystemID[] getDevices(ObjectID oid)

Returns an array of system ids that have been discovered recently and that contain the specified well known service.

Parameters:

oid - The well known object id to lookup.

Returns:

An array of system ids of devices that have the specified well known service.

getDevices

public SystemID[] getDevices(ObjectID[] ids)

Returns an array of system ids that consists of systems that contain the specified well known services.

Parameters:

ids - An array of ids to lookup.

Returns:

The systems that contain the specified services.

getRemoteDevices

public SystemID[] getRemoteDevices()

Returns an array of remote system id that has been discovered recently.

Returns:

The remote devices that have been discovered.

getRemoteDevices

public SystemID[] getRemoteDevices(ObjectID oid)

Returns an array of remote system ids that have been discovered recently and that contain the specified well known service.

Parameters:

oid - The well known object id to lookup.

Returns:

An array of remote system ids of devices that have the specified well known service.

getRemoteDevices

public SystemID[] getRemoteDevices(ObjectID[] ids)

Returns an array of remote system ids that consists of systems that contain the specified well known services.

Parameters:

ids - An array of ids to lookup.

Returns:

The remote systems that contain the specified services.

getDeviceDescription

public DeviceDescription getDeviceDescription(SystemID id)

Returns the device description of the system with the specified id.

Parameters:

id - The system id of the device description to lookup.

Returns:

The device description of the system with the specified id or null if the device description is not known.

registerPlugin

public void registerPlugin(SystemID id,
                  PluginDescription plugin,
                  long ttl)

Registers the specified plug-in description of the specified device. If the plug-in description has been registered before, it will be overwritten. The plug-in description stays registered as long as the ttl has not run out.

Parameters:

id - The id of the device.

plugin - The plug-in description to register.

ttl - The time to live.

registerPlugin

public void registerPlugin(SystemID id,
                  PluginDescription plugin)

Registers the specified plug-in description of the specified device. The plug-in stays registered until the remove method is called.

Parameters:

id - The system id of the plug-in to register.

plugin - The plug-in description to register.

removePlugin

public void removePlugin(SystemID id,
                PluginDescription plugin)

Removes the specified plug-in from the set of permanently registered plug-ins.

Parameters:

id - The id of the system.

plugin - The plug-in description to remove.

getPluginDescriptions

public PluginDescription[] getPluginDescriptions(SystemID source,
                                        SystemID target)

Returns the plug-in descriptions of the target system that are compatible with the source system.

Parameters:

source - The system id of the source system.

target - The system id of the target system.

Returns:

The set of plug-in descriptions of the target system that are compatible with the remote system.

getPluginDescriptions

public PluginDescription[] getPluginDescriptions(SystemID systemID)

Returns a set of plug-in descriptions which have been registered for a given system. Note that this method will also work for the local system.

Parameters:

systemID - The system id of the system to lookup.

Returns:

The plug-in descriptions of the specified system.

perform

public void perform(IMonitor monitor)
             throws java.lang.Exception

This operation continuously removes the devices and plug-ins from the registry whose ttl has been run out.

Specified by:

perform in interface IOperation

Parameters:

monitor - The monitor used to cancel the operation.

Throws:

java.lang.Exception - Should never happen.