info.pppc.base.system

Class PluginManager

java.lang.Object

info.pppc.base.system.PluginManager

All Implemented Interfaces:

IExtension, IOperator, IDiscoveryManager, IPluginManager, IRoutingManager, ISemanticManager, ITransceiverManager

public final class PluginManager
extends java.lang.Object
implements IPluginManager, ISemanticManager, ITransceiverManager, IDiscoveryManager, IRoutingManager, IExtension

This class is the core of the plug-in architecture. It loads plug-ins and provides supportive functionality. The plug-in manager also provides a default implementation of the plug-in strategy that does not perform any plug-in ordering.

Author:

Marcus Handte

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	PluginManager.Session The session implementation used by the plug-in manager.
class	PluginManager.SessionStrategy The default session strategy that is used in all cases where no specialized strategy is available.

Field Summary

Fields

Modifier and Type	Field and Description
static long	GROUP_RETRY The timeout between retries for opening group connectors.
static int	PACKET_LENGTH The packet length of this core.

Fields inherited from interface info.pppc.base.system.plugin.IDiscoveryManager

EVENT_PLUGIN_ADDED, EVENT_PLUGIN_REMOVED

Fields inherited from interface info.pppc.base.system.IExtension

EXTENSION_COMPRESSION, EXTENSION_DISCOVERY, EXTENSION_ENCRYPTION, EXTENSION_ROUTING, EXTENSION_SEMANTIC, EXTENSION_SERIALIZATION, EXTENSION_TRANSCEIVER

Method Summary

Methods

Modifier and Type	Method and Description
void	acceptSession(IStreamConnector c) Called by transceiver plug-ins whenever a new connector is opened by a remote device.
void	addPlugin(IPlugin plugin) Adds and starts the specified plug-in.
void	addPluginListener(int type, IListener listener) Adds a plug-in listener to the set of registered plug-ins listeners.
void	addPlugins(IPlugin[] newPlugins) Add a set of plug-ins to this manager.
ISession	createSession(SystemID target, short ability) Creates a session to communicate with the specified target.
void	dispatchSynchronous(Invocation invocation, ISession session) Called by a semantic plug-in to deliver an incoming invocation to the broker.
DeviceDescription	getDeviceDescription(SystemID system) Returns the device description of the local device.
SystemID[]	getDevices() Returns the devices that are present in the environment.
PluginDescription[]	getPluginDescriptions(SystemID system) Returns the plug-in descriptions of the specified device.
IPlugin[]	getPlugins() Returns the plug-ins that are currently installed and managed by this plug-in manager.
IPacketConnector	openGroup(short group) Opens a group connector with all transceivers to the specified group.
IPacketConnector	openGroup(short group, short ability) Opens a group connector with transceivers that have the specified ability.
IStreamConnector	openSession(ISession session) Called by a semantic plug-in whenever a connector is required to deliver an invocation or to perform some remote communication.
void	performOperation(IOperation operation) Performs the specified operation using the invocation broker that is bound to this plug-in manager.
void	performOperation(IOperation operation, IMonitor monitor) Performs the specified operation using the specified operation monitor.
ISession	prepareSession(ISession session, NFCollection requirements) Called by a semantic plug-in whenever the semantic plug-in tries to recreate a communication stack, possibly with different properties.
void	registerDevice(DeviceDescription device, long ttl) Registers the specified device description of the specified system.
void	registerPlugin(SystemID id, PluginDescription plugin, long ttl) Registers the specified plug-in description of the specified remote device.
void	removePlugin(IPlugin plugin) Removes the specified plug-in from the set of plug-ins that are installed and managed by this plug-in manager.
boolean	removePluginListener(int type, IListener listener) Removes a previously registered plug-in listener from the set of registered plug-in listeners.
void	setStrategy(ISessionStrategy newStrategy) Sets the strategy used by the plug-in manager.

Methods inherited from class java.lang.Object

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

Field Detail

PACKET_LENGTH

public static final int PACKET_LENGTH

The packet length of this core.

See Also:

Constant Field Values

GROUP_RETRY

public static final long GROUP_RETRY

The timeout between retries for opening group connectors.

See Also:

Constant Field Values

Method Detail

addPlugins

public void addPlugins(IPlugin[] newPlugins)

Add a set of plug-ins to this manager. This method updates internal data structures, sets call backs and starts plug-ins.

Parameters:

newPlugins - A set of local plug-ins.

addPlugin

public void addPlugin(IPlugin plugin)

Adds and starts the specified plug-in. This method updates internal data structures, sets the call back and starts the plug-in.

Parameters:

plugin - The plug-in to add.

removePlugin

public void removePlugin(IPlugin plugin)

Removes the specified plug-in from the set of plug-ins that are installed and managed by this plug-in manager.

Parameters:

plugin - The plug-in that should be removed.

getPlugins

public IPlugin[] getPlugins()

Returns the plug-ins that are currently installed and managed by this plug-in manager.

Returns:

The installed plug-ins that are currently managed by this plug-in manager.

setStrategy

public void setStrategy(ISessionStrategy newStrategy)

Sets the strategy used by the plug-in manager.

Parameters:

newStrategy - The strategy of the plug-in manager.

createSession

public ISession createSession(SystemID target,
                     short ability)

Creates a session to communicate with the specified target.

Specified by:

createSession in interface ISemanticManager

Parameters:

target - The target of the call.

ability - The ability of the calling plug-in.

Returns:

The session object.

prepareSession

public ISession prepareSession(ISession session,
                      NFCollection requirements)

Called by a semantic plug-in whenever the semantic plug-in tries to recreate a communication stack, possibly with different properties.

Specified by:

prepareSession in interface ISemanticManager

Parameters:

session - The session that was originally negotiated. This session is used as blueprint for the new session to create.

requirements - The nf-requirements. They might have changed since the last negotiation of the provided session.

Returns:

The prepared session for the specified parameters.

openSession

public IStreamConnector openSession(ISession session)
                             throws java.io.IOException

Called by a semantic plug-in whenever a connector is required to deliver an invocation or to perform some remote communication.

Specified by:

openSession in interface ISemanticManager

Parameters:

session - The session information used to create the connector.

Returns:

A stream connector that is composed from the session parameters.

Throws:

java.io.IOException - Thrown if the connector cannot be opened.

acceptSession

public void acceptSession(IStreamConnector c)

Called by transceiver plug-ins whenever a new connector is opened by a remote device. This implementation tries to read the session information from the input stream and creates a communication stack according to the specification provided by the remote plug-in manager. See the open session command for details.

Specified by:

acceptSession in interface ITransceiverManager

Parameters:

c - The connector that has been opened by a remote device.

dispatchSynchronous

public void dispatchSynchronous(Invocation invocation,
                       ISession session)

Called by a semantic plug-in to deliver an incoming invocation to the broker. This method simply forwards the incoming invocation.

Specified by:

dispatchSynchronous in interface ISemanticManager

Parameters:

invocation - The invocation that has been received.

session - The session used to receive the invocation.

getPluginDescriptions

public PluginDescription[] getPluginDescriptions(SystemID system)

Returns the plug-in descriptions of the specified device. This implementation simply forwards the request to the local device registry.

Specified by:

getPluginDescriptions in interface IPluginManager

Parameters:

system - The system id of the system.

Returns:

The plug-in descriptions of visible plug-ins of the system

getDeviceDescription

public DeviceDescription getDeviceDescription(SystemID system)

Returns the device description of the local device. This implementation simply forwards the request to the device registry.

Specified by:

getDeviceDescription in interface IPluginManager

Parameters:

system - The system to retrieve.

Returns:

The device description of the local system.

getDevices

public SystemID[] getDevices()

Returns the devices that are present in the environment.

Specified by:

getDevices in interface IPluginManager

Returns:

The available devices.

addPluginListener

public void addPluginListener(int type,
                     IListener listener)

Adds a plug-in listener to the set of registered plug-ins listeners.

Specified by:

addPluginListener in interface IDiscoveryManager

Parameters:

type - The types of events to register for.

listener - The listener to register.

removePluginListener

public boolean removePluginListener(int type,
                           IListener listener)

Removes a previously registered plug-in listener from the set of registered plug-in listeners.

Specified by:

removePluginListener in interface IDiscoveryManager

Parameters:

type - The types of events to unregister for.

listener - The listener to unregister.

Returns:

True if the listener has been removed, false otherwise.

registerDevice

public void registerDevice(DeviceDescription device,
                  long ttl)

Registers the specified device description of the specified system. The device description stays valid for the specified time to live. This implementation simply forwards the device description to the device registry of the broker.

Specified by:

registerDevice in interface IDiscoveryManager

Parameters:

device - The device description of the remote system.

ttl - The time to live for the device description in milliseconds.

registerPlugin

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

Registers the specified plug-in description of the specified remote device. The plug-in description stays valid for the specified time to live. This method of the plug-in manager simply forwards the request to the device registry.

Specified by:

registerPlugin in interface IDiscoveryManager

Parameters:

id - The id of the system that hosts the plug-in.

plugin - The plug-in description to register.

ttl - The time to live in milliseconds.

openGroup

public IPacketConnector openGroup(short group)

Opens a group connector with all transceivers to the specified group.

Specified by:

openGroup in interface IDiscoveryManager

Parameters:

group - The group to connect to.

Returns:

The packet connector for this group and plug-in.

openGroup

public IPacketConnector openGroup(short group,
                         short ability)

Opens a group connector with transceivers that have the specified ability.

Specified by:

openGroup in interface IDiscoveryManager

Parameters:

group - The group to connect to.

ability - The ability of the plug-in to use.

Returns:

The packet connector for this group and plug-in.

performOperation

public void performOperation(IOperation operation)

Performs the specified operation using the invocation broker that is bound to this plug-in manager.

Specified by:

performOperation in interface IOperator

Parameters:

operation - The operation to perform.

performOperation

public void performOperation(IOperation operation,
                    IMonitor monitor)

Performs the specified operation using the specified operation monitor. The operation is executed by the invocation broker that uses this plug-in manager.

Specified by:

performOperation in interface IOperator

Parameters:

monitor - The monitor used to observe the operation.

operation - The operation to perform.