context.arch
Class BaseObject

java.lang.Object
  context.arch.BaseObject

All Implemented Interfaces:

CommunicationsHandler, MessageHandler

Direct Known Subclasses:

Interpreter, Widget

public class BaseObject

extends java.lang.Object

implements MessageHandler, CommunicationsHandler

This class is the base object for the context-aware infrastructure. It is able to poll and subscribe to other components and can be polled and subscribed to by other components. It also can generate and handle RPC-style requests. It consists of 2 main objects, the CommunicationsObject and ParserObject. It also maintains a list of subscribers and a list of handlers.

Author:

Anind

See Also:

CommunicationsObject, ParserObject, Handler

Field Summary

static java.lang.String	BASEOBJECT_TYPE The tag for the type of this object
CommunicationsObject	communications Object to handle communications between components
static boolean	DEBUG Debug flag.
static int	DISABLE_PORT Disables the communications
DiscovererDescription	discoverer The description of the discoverer that the base object has found
static int	EXIT_OK Indicates that the exit condition is normal
GenericFrame	gFrame
Handlers	handlers Object to keep track of context widget handlers
static java.lang.String	ID Tag for id of this component
ParserObject	parser Object to handle the encoding and decoding of communications
static java.lang.String	PING Tag for a ping
static java.lang.String	PING_REPLY Tag for a ping reply
static java.lang.String	QUERY_DESCRIPTION Tag for getting the description
static java.lang.String	QUERY_DESCRIPTION_REPLY Tag for reply to a query_description
AsyncServiceHandlers	serviceHandlers Object to keep track of asynchronous service handlers

Constructor Summary

BaseObject()
Basic constructor that creates a CommunicationsObject, ParserObject and Handlers object.

BaseObject(int localServerPort)
Constructor that just creates a CommunicationsObject with the given port and ParserObject.

BaseObject(int localServerPort, java.lang.String protocolHandlerClass)
Constructor that just creates a CommunicationsObject with the given port and protocol handler class, and ParserObject.

BaseObject(java.lang.String protocolHandlerClass)
Constructor that just creates a CommunicationsObject with the given protocol handler class, and a ParserObject.

BaseObject(java.lang.String communicationClientClass, java.lang.String communicationServerClass, int localServerPort, java.lang.String encoderClass, java.lang.String decoderClass)
Basic constructor that creates a CommunicationsObject with the given port and protocol, and creates a ParserObject with the given encoder and decoder.

BaseObject(java.lang.String communicationClientClass, java.lang.String communicationServerClass, int localServerPort, java.lang.String encoderClass, java.lang.String decoderClass, int threadPoolNumber)
Basic constructor that creates a CommunicationsObject with the given port and protocol, and creates a ParserObject with the given encoder and decoder.

Method Summary

void	activateDisplay() Activate the display
DataObject	askInterpreter(java.lang.String remoteHost, int remotePort, java.lang.String remoteId, Attributes data) This method asks an interpreter to interpret some data.
void	deactivateDisplay() Deactivate the display
static void	debugprintln(boolean DEBUG_flag, java.lang.Object s) Print a message if the DEBUG mode is active
DataObject	decodeData(java.io.Reader communicationData) Stub method that decodes the given string using ParserObject
java.util.Vector	discovererQuery(AbstractQueryItem query) This method allows to send a query to the discoverer.
protected DataObject	discovererQuery(DataObject data) This method allows to send a query to the discoverer containing the description of the context component the object would like to know.
Error	discovererRegistration() This method is used to send the component description to the discoverer.
Error	discovererRegistration(Lease registrationLease) This method is used to send the component description to the discoverer.
protected DataObject	discovererSendSubscription(Handler handler, DiscovererSubscriber discoSub) to improve
void	discovererSubscribe(Handler handler, DiscovererSubscriber discoSub) This method is used to subscribe to the discoverer.
DataObject	discovererSubscriptionNotification(DataObject data)
Error	discovererUnregistration() This method allows to unregister from the discoverer
Error	discovererUpdate() This method allows to send a message to the discoverer to update its own description stored in the discoverer.
java.lang.String	encodeData(DataObject communicationData) Stub method that encodes the given string using ParserObject
DataObject	executeAsynchronousWidgetService(AsyncServiceHandler handler, java.lang.String serviceHost, int servicePort, java.lang.String serviceId, java.lang.String service, java.lang.String function, Attributes input, java.lang.String requestTag) This method requests that a widget execute an asynchronous service
DataObject	executeSynchronousWidgetService(java.lang.String remoteHost, int remotePort, java.lang.String remoteId, java.lang.String service, java.lang.String function, Attributes input) This method requests that a widget execute a synchronous service
Error	findDiscoverer() This method allows to find a discoverer.
Error	findDiscoverer(boolean registration) This method allows to find a discoverer.
Error	findDiscoverer(boolean registration, Lease registrationLease, boolean automaticRenewal) This method allows to find a discoverer.
ComponentDescription	getComponentDescription()
DataObject	getDescription() Returns the common description of the component.
java.lang.String	getHostAddress() This method gets the address of the machine this component is running on.
java.lang.String	getHostName() This method gets the name of the machine this component is running on.
java.lang.String	getId() This method returns the id of the class that subclass this object, for use in sending messages.
static java.lang.String	getId(java.lang.String className, int port) Returns a uniq id constructed as classname_hostname_port_givenUserLocation, or if there is an error, returns the user location given by the user.
Lease	getLease() This method allows to specify a lease used to register the discoverer.
java.lang.String	getListOfHandlers() Returns the list of handlers this object made.
java.lang.String	getLocationAddress() Returns the location address
int	getPort()
java.lang.String	getType() Returns the type of the object This method should be overridden
DataObject	getUserDescription() Returns the added description of the component That method should be overriden.
java.lang.String	getVersion() This method returns the version number of this object.
DataObject	getVersion(java.lang.String remoteHost, int remotePort, java.lang.String remoteId) This method gets the version of the given component (remoteHostname, widget, interpreter).
DataObject	getWidgetAttributes(java.lang.String widgetHost, int widgetPort, java.lang.String widgetId) This method gets the attributes of the given widget
DataObject	getWidgetCallbacks(java.lang.String widgetHost, int widgetPort, java.lang.String widgetId) This method gets the callbacks of the given widget
DataObject	getWidgetConstantAttributes(java.lang.String widgetHost, int widgetPort, java.lang.String widgetId) This method gets the attributes of the given widget
DataObject	getWidgetServices(java.lang.String widgetHost, int widgetPort, java.lang.String widgetId) This method gets the services of the given widget
void	handleIndependentReply(IndependentCommunication independentCommunication) This method is called after the independentUserRequest has been called.
void	independentUserRequest(IndependentCommunication request) This method is used to send a message through a threaded communication.
protected DataObject	leaseEndNotified(DataObject data) This method sends a lease end confirmation if necessary.
void	pingComponent(IndependentCommunication independentCommunication)
DataObject	pingComponent(java.lang.String remoteHost, int remotePort, java.lang.String remoteId, boolean independentCom) This method pings a component (widget,remoteHostname, or interpreter) to make sure that it is functioning ok.
DataObject	pollWidget(java.lang.String widgetHost, int widgetPort, java.lang.String widgetId, Attributes attributes) This method allows a component to poll a remote widget for its attribute values.
void	println(java.lang.String s) Print a string, on the displayed frame if it is activated or on the default output stream.
DataObject	putDataInWidget(java.lang.String widgetHost, int widgetPort, java.lang.String widgetId, java.lang.String callback, Attributes attributes) This method allows a component to put context data in a remote widget.
DataObject	queryVersion(DataObject query) This method returns the version number of this component.
void	quit() This method should be called when the object is going to exit under normal conditions.
DataObject	retrieveDataFrom(java.lang.String remoteHost, int remotePort, java.lang.String remoteId, Retrieval retrieval) This method allows a component to retrieve data from other components.
DataObject	retrieveDataFrom(java.lang.String remoteHost, int remotePort, java.lang.String remoteId, java.lang.String myId, Retrieval retrieval) This method allows a component to retrieve data from other components.
DataObject	returnPing(DataObject ping) This method returns an error message as an answer to a ping.
DataObject	runComponentMethod(java.lang.String remoteHost, int remotePort, java.lang.String remoteId, java.lang.String methodName, Attributes parameters, Attributes attributes) This method asks an component to run some non-standard method.
DataObject	runMethod(java.lang.String methodType, DataObject data) This method handles both the system-defined, callbacks and user-defined RPCs.
DataObject	runUserMethod(DataObject data) This is an empty method that should be overridden by the object that extends this class.
DataObject	serviceResult(DataObject result) This method handles the results of an asynchronous service request.
void	setAllDebug(boolean baseObjectDebug, boolean communicationDebug, boolean componentDebug) Set the CTK classes in the DEBUG status
DataObject	setDiscoverer(DataObject data) This method handles the lookup response from the discoverer.
void	setDisplay() Create the display and activate it
void	setDisplay(GenericFrame frame)
void	setDisplayName(java.lang.String objName) Set the title displayed on the frame
void	setDisplayTitle(java.lang.String title) Set the title of the frame
void	setId(java.lang.String id) This method sets the id of classes that subclass this object, for use in sending messages.
void	setLease(Lease lease) Set the lease used to register the discoverer
void	setLocationAddress(java.lang.String location) Sets the location address (structured as for example GT/CRB/Floor1/Hall2/room4
void	setVersion(java.lang.String version) This method sets the version number of this object.
Error	subscribeTo(Handler handler, java.lang.String remoteId, java.lang.String remoteHost, int remotePort, ClientSideSubscriber subscriber) This method allows a component to subscribe to changes in other components.
Error	unsubscribeFrom(java.lang.String subscriptionId) This method allows a component to unsubscribe from another component.
DataObject	updateAndPollWidget(java.lang.String widgetHost, int widgetPort, java.lang.String widgetId, Attributes attributes) This method allows a component to force a remote widget to update its data and return it.
DataObject	userCallback(DataObject data) This method is called when a callback message is received.
DataObject	userRequest(DataObject data, java.lang.String requestType) Deprecated.
DataObject	userRequest(DataObject data, java.lang.String requestType, java.lang.String remoteHostname) Deprecated.
DataObject	userRequest(DataObject data, java.lang.String requestType, java.lang.String remoteHostname, int remotePort) Method that submits a user request for polling/subscription.
DataObject	userRequest(RequestObject request) Sends a message to a remote component

Methods inherited from class java.lang.Object

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

Field Detail

DEBUG

public static boolean DEBUG

Debug flag. Set to true to see debug messages.

EXIT_OK

public static final int EXIT_OK

Indicates that the exit condition is normal

See Also:

Constant Field Values

DISABLE_PORT

public static final int DISABLE_PORT

Disables the communications

See Also:

Constant Field Values

ID

public static final java.lang.String ID

Tag for id of this component

See Also:

Constant Field Values

PING

public static final java.lang.String PING

Tag for a ping

See Also:

Constant Field Values

PING_REPLY

public static final java.lang.String PING_REPLY

Tag for a ping reply

See Also:

Constant Field Values

QUERY_DESCRIPTION

public static final java.lang.String QUERY_DESCRIPTION

Tag for getting the description

See Also:

Constant Field Values

QUERY_DESCRIPTION_REPLY

public static final java.lang.String QUERY_DESCRIPTION_REPLY

Tag for reply to a query_description

See Also:

Constant Field Values

BASEOBJECT_TYPE

public static final java.lang.String BASEOBJECT_TYPE

The tag for the type of this object

See Also:

Constant Field Values

communications

public CommunicationsObject communications

Object to handle communications between components

See Also:

CommunicationsObject

parser

public ParserObject parser

Object to handle the encoding and decoding of communications

See Also:

ParserObject

handlers

public Handlers handlers

Object to keep track of context widget handlers

See Also:

Handlers, Handler

serviceHandlers

public AsyncServiceHandlers serviceHandlers

Object to keep track of asynchronous service handlers

See Also:

AsyncServiceHandlers, AsyncServiceHandler

gFrame

public GenericFrame gFrame

discoverer

public DiscovererDescription discoverer

The description of the discoverer that the base object has found

See Also:

Discoverer

Constructor Detail

BaseObject

public BaseObject(java.lang.String communicationClientClass,
                  java.lang.String communicationServerClass,
                  int localServerPort,
                  java.lang.String encoderClass,
                  java.lang.String decoderClass,
                  int threadPoolNumber)

Basic constructor that creates a CommunicationsObject with the given port and protocol, and creates a ParserObject with the given encoder and decoder. It also creates a Handlers object to keep track of context widget handlers.

Parameters:

communicationClientClass - Class to use for client communications

communicationServerClass - Class to use for server communications

localServerPort - Port to use for server communications

encoderClass - Class to use for communications encoding

decoderClass - Class to use for communications decoding

threadPoolNumber - The number of client threads in the clients pool

See Also:

CommunicationsObject, CommunicationsObject.start(), ParserObject, Handlers

BaseObject

public BaseObject(java.lang.String communicationClientClass,
                  java.lang.String communicationServerClass,
                  int localServerPort,
                  java.lang.String encoderClass,
                  java.lang.String decoderClass)

Basic constructor that creates a CommunicationsObject with the given port and protocol, and creates a ParserObject with the given encoder and decoder. It also creates a Handlers object to keep track of context widget handlers.

Parameters:

communicationClientClass - Class to use for client communications

communicationServerClass - Class to use for server communications

localServerPort - Port to use for server communications

encoderClass - Class to use for communications encoding

decoderClass - Class to use for communications decoding

See Also:

CommunicationsObject, CommunicationsObject.start(), ParserObject, Handlers

BaseObject

public BaseObject()

Basic constructor that creates a CommunicationsObject, ParserObject and Handlers object.

See Also:

CommunicationsObject, CommunicationsObject.start(), ParserObject, Handlers

BaseObject

public BaseObject(int localServerPort)

Constructor that just creates a CommunicationsObject with the given port and ParserObject. It also creates a Handlers object to keep track of context widget handlers.

Parameters:

localServerPort - Port number to communicate on

See Also:

CommunicationsObject, CommunicationsObject.start(), ParserObject, Handlers

BaseObject

public BaseObject(java.lang.String protocolHandlerClass)

Constructor that just creates a CommunicationsObject with the given protocol handler class, and a ParserObject. It also creates a Handlers object to keep track of context widget handlers.

Parameters:

protocolHandlerClass - Protocol handler class to communicate with

See Also:

CommunicationsObject, CommunicationsObject.start(), ParserObject, Handlers

BaseObject

public BaseObject(int localServerPort,
                  java.lang.String protocolHandlerClass)

Constructor that just creates a CommunicationsObject with the given port and protocol handler class, and ParserObject. It also creates a Handlers object to keep track of context widget handlers.

Parameters:

localServerPort - Port number to communicate on

protocolHandlerClass - Protocol handler class name to communicate with

See Also:

CommunicationsObject, CommunicationsObject.start(), ParserObject, Handlers

Method Detail

decodeData

public DataObject decodeData(java.io.Reader communicationData)
                      throws DecodeException,
                             InvalidDecoderException

Stub method that decodes the given string using ParserObject

Specified by:

decodeData in interface MessageHandler

Parameters:

communicationData - String to be decoded

Returns:

the decoded data

Throws:

DecodeException - thrown if the parser can't decode the given string

InvalidDecoderException - thrown if the parser can't create the necessary decoder

See Also:

ParserObject.decodeData(java.io.Reader)

encodeData

public java.lang.String encodeData(DataObject communicationData)
                            throws EncodeException,
                                   InvalidEncoderException

Stub method that encodes the given string using ParserObject

Specified by:

encodeData in interface MessageHandler

Parameters:

communicationData - String to be decoded

Returns:

the encoded data

Throws:

EncodeException - thrown if the parser can't encode the given string

InvalidEncoderException - thrown if the parser can't create the necessary encoder

See Also:

ParserObject.encodeData(context.arch.comm.DataObject)

userRequest

public DataObject userRequest(DataObject data,
                              java.lang.String requestType)
                       throws EncodeException,
                              InvalidProtocolException,
                              ProtocolException,
                              DecodeException,
                              InvalidDecoderException,
                              InvalidEncoderException,
                              java.io.IOException

Deprecated.

Method that submits a user request for polling/subscription. The request is in the form of a DataObject. It is encoded, sent out and the reply is decoded, if necessary, and returned.

Specified by:

userRequest in interface CommunicationsHandler

Parameters:

data - DataObject that contains the request

requestType - RPC tag that indicates the type of request

Returns:

DataObject containing the reply to the request

Throws:

EncodeException - when the encoding can't be completed successfully

DecodeException - when the decoding can't be completed successfully

InvalidEncoderException - when the encoder can't be created

InvalidDecoderException - when the decoder can't be created

ProtocolException - when the request can't be sent successfully

InvalidProtocolException - when the request can't be sent successfully due to invalid protocol use

java.io.IOException

userRequest

public DataObject userRequest(RequestObject request)
                       throws EncodeException,
                              InvalidProtocolException,
                              ProtocolException,
                              DecodeException,
                              InvalidDecoderException,
                              InvalidEncoderException,
                              java.io.IOException

Sends a message to a remote component

Specified by:

userRequest in interface CommunicationsHandler

Parameters:

request - The RequestObject that contains all information about the remote component and the data to send

Returns:

DataObject The reply

Throws:

InvalidProtocolException - when the request can't be sent successfully due to invalid protocol use

DecodeException - when the decoding can't be completed successfully

EncodeException - when the encoding can't be completed successfully

ProtocolException - when the request can't be sent successfully

InvalidEncoderException - when the encoder can't be created

InvalidDecoderException - when the decoder can't be created

java.io.IOException

userRequest

public DataObject userRequest(DataObject data,
                              java.lang.String requestType,
                              java.lang.String remoteHostname)
                       throws EncodeException,
                              InvalidProtocolException,
                              ProtocolException,
                              DecodeException,
                              InvalidDecoderException,
                              InvalidEncoderException,
                              java.io.IOException

Deprecated.

Method that submits a user request for polling/subscription. The request is in the form of a DataObject. It is encoded, sent out and the reply is decoded, if necessary, and returned.

Specified by:

userRequest in interface CommunicationsHandler

Parameters:

data - DataObject that contains the request

requestType - RPC tag that indicates the type of request

remoteHostname - Hostname of the component the request is being sent to

Returns:

DataObject containing the reply to the request

Throws:

EncodeException - when the encoding can't be completed successfully

DecodeException - when the decoding can't be completed successfully

InvalidEncoderException - when the encoder can't be created

InvalidDecoderException - when the decoder can't be created

ProtocolException - when the request can't be sent successfully

InvalidProtocolException - when the request can't be sent successfully due to invalid protocol use

java.io.IOException

userRequest

public DataObject userRequest(DataObject data,
                              java.lang.String requestType,
                              java.lang.String remoteHostname,
                              int remotePort)
                       throws EncodeException,
                              ProtocolException,
                              InvalidProtocolException,
                              DecodeException,
                              InvalidDecoderException,
                              InvalidEncoderException,
                              java.io.IOException

Method that submits a user request for polling/subscription. The request is in the form of a DataObject. It is encoded, sent out and the reply is decoded, if necessary, and returned.

Specified by:

userRequest in interface CommunicationsHandler

Parameters:

data - DataObject that contains the request

requestType - RPC tag that indicates the type of request

remoteHostname - Hostname of the component the request is being sent to

remotePort - Port number of the component the request is being sent to

Returns:

DataObject containing the reply to the request

Throws:

EncodeException - when the encoding can't be completed successfully

DecodeException - when the decoding can't be completed successfully

InvalidEncoderException - when the encoder can't be created

InvalidDecoderException - when the decoder can't be created

ProtocolException - when the request can't be sent successfully

InvalidProtocolException - when the request can't be sent successfully due to invalid protocol use

java.io.IOException

independentUserRequest

public void independentUserRequest(IndependentCommunication request)
                            throws EncodeException,
                                   InvalidEncoderException

This method is used to send a message through a threaded communication. The request is sent by a thread in charge of the communication. The request is encapsulated in a IndependentCommunication that contains a RequestObject (data to send and the recipient of the data) and the reply message and the exceptions that occured during the communication. If the communication result is null, the baseObject won't be notified about how the communication ended. Actually, the thread in charge of the communication won't notify the baseObject, but update the request object. If the result is not null, result is the IndependentCommunications object that will contain the original request and the reply. At the end of the communication, the thread updates request with the reply message and the exception, and adds it into result. The base object is notified of the end of the threaded communication when the handleIndependentReply is called by the thread.

Specified by:

independentUserRequest in interface CommunicationsHandler

Parameters:

request - The IndependentCommunication object that contain the RequestObject, and will contain after the communication the reply dataObject and the vector of exception

Throws:

EncodeException

InvalidEncoderException

See Also:

handleIndependentReply(context.arch.comm.clients.IndependentCommunication), IndependentCommunication, context.arch.comm.clients.IndependentCommunications, context.arch.util.RequesObject

handleIndependentReply

public void handleIndependentReply(IndependentCommunication independentCommunication)

This method is called after the independentUserRequest has been called. The thread in charge of the communication sends the results to this method. This method should be overridden by classes that need to handle the responses.

Specified by:

handleIndependentReply in interface MessageHandler

See Also:

ClientsPool, Client, context.arch.util.RequestObject, DataObject

subscribeTo

public Error subscribeTo(Handler handler,
                         java.lang.String remoteId,
                         java.lang.String remoteHost,
                         int remotePort,
                         ClientSideSubscriber subscriber)

This method allows a component to subscribe to changes in other components. The subscription includes the handler that will handle the callbacks, the subscriber's hostname and port, the subscription id, the remote component's hostname, port, and id, the remote component's callback, and the name of the subscriber's method that will handle the callback.

Parameters:

handler - Object that handles context widget callbacks

remoteId - Id of the context widget being subscribed to

remoteHost - Hostname of the widget being subscribed to

remotePort - Port number of the widget being subscribed to

subscriber - Subscriber object holding the subscription info

Returns:

Error to indicate success of subscription

See Also:

Handlers, Handlers.addHandler(context.arch.handler.HandlerInfo), userRequest(context.arch.comm.DataObject, String, String, int)

unsubscribeFrom

public Error unsubscribeFrom(java.lang.String subscriptionId)

This method allows a component to unsubscribe from another component.

Returns:

Error to indicate success of unsubscription

See Also:

Handlers, Handlers.removeHandler(context.arch.handler.HandlerInfo), userRequest(context.arch.comm.DataObject, String, String, int)

pollWidget

public DataObject pollWidget(java.lang.String widgetHost,
                             int widgetPort,
                             java.lang.String widgetId,
                             Attributes attributes)

This method allows a component to poll a remote widget for its attribute values. A list of attributes is provided to dictate which attribute values are wanted.

Parameters:

widgetHost - Hostname of the context widget being polled

widgetPort - Port number of the context widget being polled

widgetId - Id of the context widget being polled

attributes - Attributes being requested

Returns:

DataObject containing results of poll

See Also:

userRequest(context.arch.comm.DataObject, String, String, int)

updateAndPollWidget

public DataObject updateAndPollWidget(java.lang.String widgetHost,
                                      int widgetPort,
                                      java.lang.String widgetId,
                                      Attributes attributes)

This method allows a component to force a remote widget to update its data and return it. A list of attributes is provided to dictate which attribute values are wanted.

Parameters:

widgetHost - Hostname of the context widget being polled

widgetPort - Port number of the context widget being polled

widgetId - Id of the context widget being polled

attributes - Attributes being requested

Returns:

DataObject containing results of poll

See Also:

userRequest(context.arch.comm.DataObject, String, String, int)

putDataInWidget

public DataObject putDataInWidget(java.lang.String widgetHost,
                                  int widgetPort,
                                  java.lang.String widgetId,
                                  java.lang.String callback,
                                  Attributes attributes)

This method allows a component to put context data in a remote widget. It is really intended for components that don't use the context toolkit, but is being included here for possible future use. The method takes a callback and an AttributeNameValues object. The callback is not necessary (can have a null value), and is only used by the remote widget to determine which of the widget's subscribers need to be updated.

Parameters:

widgetHost - Hostname of the context widget to use

widgetPort - Port number of the context widget to use

widgetId - Id of the context widget to use

callback - Callback of the context widget to associate the data with

attributes - AttributeNameValues to put in the widget

Returns:

DataObject containing results of put data

See Also:

userRequest(context.arch.comm.DataObject, String, String, int)

getVersion

public DataObject getVersion(java.lang.String remoteHost,
                             int remotePort,
                             java.lang.String remoteId)

This method gets the version of the given component (remoteHostname, widget, interpreter).

Parameters:

remoteHost - Hostname of the component being queried

remotePort - Port number of the component being queried

remoteId - Id of the component being queried

Returns:

DataObject containing version

See Also:

userRequest(context.arch.comm.DataObject, String, String, int)

getWidgetCallbacks

public DataObject getWidgetCallbacks(java.lang.String widgetHost,
                                     int widgetPort,
                                     java.lang.String widgetId)

This method gets the callbacks of the given widget

Parameters:

widgetHost - Hostname of the widget being queried

widgetPort - Port number of the widget being queried

widgetId - Id of the widget being queried

Returns:

DataObject containing callbacks

See Also:

userRequest(context.arch.comm.DataObject, String, String, int)

getWidgetServices

public DataObject getWidgetServices(java.lang.String widgetHost,
                                    int widgetPort,
                                    java.lang.String widgetId)

This method gets the services of the given widget

Parameters:

widgetHost - Hostname of the widget being queried

widgetPort - Port number of the widget being queried

widgetId - Id of the widget being queried

Returns:

DataObject containing services of the widget

See Also:

userRequest(context.arch.comm.DataObject, String, String, int)

getWidgetAttributes

public DataObject getWidgetAttributes(java.lang.String widgetHost,
                                      int widgetPort,
                                      java.lang.String widgetId)

This method gets the attributes of the given widget

Parameters:

widgetHost - Hostname of the widget being queried

widgetPort - Port number of the widget being queried

widgetId - Id of the widget being queried

Returns:

DataObject containing callbacks

See Also:

userRequest(context.arch.comm.DataObject, String, String, int)

getWidgetConstantAttributes

public DataObject getWidgetConstantAttributes(java.lang.String widgetHost,
                                              int widgetPort,
                                              java.lang.String widgetId)

This method gets the attributes of the given widget

Parameters:

widgetHost - Hostname of the widget being queried

widgetPort - Port number of the widget being queried

widgetId - Id of the widget being queried

Returns:

DataObject containing callbacks

See Also:

userRequest(context.arch.comm.DataObject, String, String, int)

retrieveDataFrom

public DataObject retrieveDataFrom(java.lang.String remoteHost,
                                   int remotePort,
                                   java.lang.String remoteId,
                                   Retrieval retrieval)

This method allows a component to retrieve data from other components.

Parameters:

remoteHost - Hostname of the component being asked for data

remotePort - Port number of the component being asked for data

remoteId - Id of the component being asked for data

retrieval - Description of data to retrieve with any conditions

Returns:

DataObject containing data requested

See Also:

userRequest(context.arch.comm.DataObject, String, String, int)

retrieveDataFrom

public DataObject retrieveDataFrom(java.lang.String remoteHost,
                                   int remotePort,
                                   java.lang.String remoteId,
                                   java.lang.String myId,
                                   Retrieval retrieval)

This method allows a component to retrieve data from other components.

Parameters:

remoteHost - Hostname of the component being asked for data

remotePort - Port number of the component being asked for data

remoteId - Id of the component being asked for data

myId - Id of the "user" trying to access the data

retrieval - Description of data to retrieve with any conditions

Returns:

DataObject containing data requested

See Also:

userRequest(context.arch.comm.DataObject, String, String, int)

askInterpreter

public DataObject askInterpreter(java.lang.String remoteHost,
                                 int remotePort,
                                 java.lang.String remoteId,
                                 Attributes data)

This method asks an interpreter to interpret some data. It passes the data to be interpreted and gets back the interpreted data.

Parameters:

remoteHost - Hostname of the component being asked for data

remotePort - Port number of the component being asked for data

remoteId - Id of the component being asked for data

data - AttributeNameValues object containing the data to be interpreted

Returns:

DataObject containing the interpreted data

runComponentMethod

public DataObject runComponentMethod(java.lang.String remoteHost,
                                     int remotePort,
                                     java.lang.String remoteId,
                                     java.lang.String methodName,
                                     Attributes parameters,
                                     Attributes attributes)

This method asks an component to run some non-standard method. It passes id of the component, attributes, and parameters and gets back the result of the method.

Parameters:

remoteHost - Hostname of the component

remotePort - Port number of the component

remoteId - Id of the component

methodName - Name of the method to run

parameters - AttributeNameValues object that is parameters with values

attributes - Attributes object that is parameters with values

Returns:

DataObject containing the interpreted data

executeAsynchronousWidgetService

public DataObject executeAsynchronousWidgetService(AsyncServiceHandler handler,
                                                   java.lang.String serviceHost,
                                                   int servicePort,
                                                   java.lang.String serviceId,
                                                   java.lang.String service,
                                                   java.lang.String function,
                                                   Attributes input,
                                                   java.lang.String requestTag)

This method requests that a widget execute an asynchronous service

Specified by:

executeAsynchronousWidgetService in interface CommunicationsHandler

Parameters:

handler - Handler to handle the results of the service

serviceHost - Hostname of the widget with the service

servicePort - Port number of the widget with the service

serviceId - Id of the widget with the service

service - Name of the widget service to run

function - Name of the particular service function to run

input - AttributeNameValues object to use to execute the service

requestTag - Unique tag provided by caller to identify result

Returns:

DataObject containing the results of the execution request

executeSynchronousWidgetService

public DataObject executeSynchronousWidgetService(java.lang.String remoteHost,
                                                  int remotePort,
                                                  java.lang.String remoteId,
                                                  java.lang.String service,
                                                  java.lang.String function,
                                                  Attributes input)

This method requests that a widget execute a synchronous service

Specified by:

executeSynchronousWidgetService in interface CommunicationsHandler

Parameters:

remoteHost - Hostname of the widget

remotePort - Port number of the widget

remoteId - Id of the widget

service - Name of the widget service to run

function - Name of the particular service function to run

input - AttributeNameValues object to use to execute the service

Returns:

DataObject containing the results of the execution request

pingComponent

public DataObject pingComponent(java.lang.String remoteHost,
                                int remotePort,
                                java.lang.String remoteId,
                                boolean independentCom)

This method pings a component (widget,remoteHostname, or interpreter) to make sure that it is functioning ok.

Parameters:

remoteHost - Hostname of the component being asked for data

remotePort - Port number of the component being asked for data

remoteId - Id of the component being asked for data

Returns:

DataObject containing the results of the ping

pingComponent

public void pingComponent(IndependentCommunication independentCommunication)

quit

public void quit()

This method should be called when the object is going to exit under normal conditions. It stops the CommunicationsObject from receiving any more requests and exits.

See Also:

CommunicationsObject.quit()

runUserMethod

public DataObject runUserMethod(DataObject data)
                         throws InvalidMethodException,
                                MethodException

This is an empty method that should be overridden by the object that extends this class. It will contain the user-defined RPCs.

Parameters:

data - DataObject containing data for user-defined RPC

Returns:

result of RPC

Throws:

InvalidMethodException - thrown if specified RPC couldn't be found

MethodException - thrown if specified RPC had an error

See Also:

runMethod(String, DataObject)

runMethod

public DataObject runMethod(java.lang.String methodType,
                            DataObject data)
                     throws InvalidMethodException,
                            MethodException

This method handles both the system-defined, callbacks and user-defined RPCs. If a user-defined RPC is called, this method calls runUserMethods. If a callback is specified, this method runs userCallback. Currently, the only system-defined methods are queryVersion, and userCallback.

Specified by:

runMethod in interface MessageHandler

Parameters:

methodType - Name of method to run

data - DataObject containing data for the method call

Throws:

InvalidMethodException - thrown if specified RPC couldn't be found

MethodException - thrown if specified RPC had an error

See Also:

userCallback(context.arch.comm.DataObject), runUserMethod(context.arch.comm.DataObject), queryVersion(context.arch.comm.DataObject), setDiscoverer(context.arch.comm.DataObject)

userCallback

public DataObject userCallback(DataObject data)

This method is called when a callback message is received. It determines which of its registered handlers should receive the callback message and passes it on accordingly. It creates a reply message to the callback request in the form of a DataObject. It handles all error checking.

Parameters:

data - DataObject containing the callback request

Returns:

DataObject containing the callback reply

See Also:

Handlers.getHandler(String), Handler.handle(String, context.arch.comm.DataObject)

getListOfHandlers

public java.lang.String getListOfHandlers()

Returns the list of handlers this object made. A handler is defined for a subscription to a widget, or the discoverer

queryVersion

public DataObject queryVersion(DataObject query)

This method returns the version number of this component.

Parameters:

query - DataObject containing the query

Returns:

DataObject containing the results of the query

returnPing

public DataObject returnPing(DataObject ping)

This method returns an error message as an answer to a ping.

Parameters:

ping - DataObject containing the ping request

Returns:

DataObject containing the results of the ping

serviceResult

public DataObject serviceResult(DataObject result)

This method handles the results of an asynchronous service request.

Parameters:

result - DataObject containing the results of the aysnchronous service request

Returns:

DataObject containing a reply to the results message

getVersion

public java.lang.String getVersion()

This method returns the version number of this object.

Returns:

version number

setVersion

public void setVersion(java.lang.String version)

This method sets the version number of this object.

Parameters:

version - of the object

setId

public void setId(java.lang.String id)

This method sets the id of classes that subclass this object, for use in sending messages.

Parameters:

id - ID of the class

getId

public java.lang.String getId()

This method returns the id of the class that subclass this object, for use in sending messages.

Returns:

id of the class

getId

public static java.lang.String getId(java.lang.String className,
                                     int port)

Returns a uniq id constructed as classname_hostname_port_givenUserLocation, or if there is an error, returns the user location given by the user.

Parameters:

className - The classname of the object

port - The port of the object

Returns:

String The uniq identification

getType

public java.lang.String getType()

Returns the type of the object This method should be overridden

Returns:

String

getHostAddress

public java.lang.String getHostAddress()

This method gets the address of the machine this component is running on.

Returns:

the address of the machine this component is running on

getHostName

public java.lang.String getHostName()

This method gets the name of the machine this component is running on.

Returns:

the name of the machine this component is running on

getPort

public int getPort()

setDiscoverer

public DataObject setDiscoverer(DataObject data)

This method handles the lookup response from the discoverer. It sets the discoverer description. And returns an error code

Returns:

DataObject En error code

See Also:

DiscovererDescription

discovererRegistration

public Error discovererRegistration()

This method is used to send the component description to the discoverer. It sends a DISCOVERER_REGISTRATION message to the discoverer with the object description. It

Returns:

Error The error code of the registration

See Also:

ComponentDescription

discovererRegistration

public Error discovererRegistration(Lease registrationLease)

This method is used to send the component description to the discoverer. It sends a DISCOVERER_REGISTRATION message to the discoverer with the object description

Returns:

Error The error code of the registration

See Also:

ComponentDescription

getComponentDescription

public ComponentDescription getComponentDescription()

getDescription

public DataObject getDescription()

Returns the common description of the component.

Returns:

DataObject It contains the component description

See Also:

ComponentDescription, getUserDescription()

setLocationAddress

public void setLocationAddress(java.lang.String location)

Sets the location address (structured as for example GT/CRB/Floor1/Hall2/room4

Parameters:

location - The location address

getLocationAddress

public java.lang.String getLocationAddress()

Returns the location address

Returns:

String The object's location address

getUserDescription

public DataObject getUserDescription()

Returns the added description of the component That method should be overriden. If not, we deduct that the current object is an application

Returns:

DataObject The description

See Also:

Discoverer

findDiscoverer

public Error findDiscoverer()

This method allows to find a discoverer. The component sends a multicast message containing its id, port, hostname. The response of the existing discoverer is handled by another method. It sends a LOOOKUP_DISCOVERER message. By default, the component registers the discoverer and the end of the lease is confirmed automatically.

Returns:

Error The error object

findDiscoverer

public Error findDiscoverer(boolean registration)

This method allows to find a discoverer. The component sends a multicast message containing its id, port, hostname. The response of the existing discoverer is handled by another method. It sends a LOOOKUP_DISCOVERER message. The component register the discoverer if registration is set true. It sends a default lease

Parameters:

registration - True if the component registers the discoverer

Returns:

Error The error object

See Also:

Lease

findDiscoverer

public Error findDiscoverer(boolean registration,
                            Lease registrationLease,
                            boolean automaticRenewal)

This method allows to find a discoverer. The component sends a multicast message containing its id, port, hostname. The response of the existing discoverer is handled by another method. It sends a LOOOKUP_DISCOVERER message. /lookup caller callerId type hostname port /caller /lookup

Returns:

Error An error code

See Also:

setDiscoverer(context.arch.comm.DataObject), Discoverer

discovererUpdate

public Error discovererUpdate()

This method allows to send a message to the discoverer to update its own description stored in the discoverer. It sends a DISCOVERER_UPDATE message.

Returns:

Error The error code received from the discoverer

See Also:

Discoverer

discovererSubscribe

public void discovererSubscribe(Handler handler,
                                DiscovererSubscriber discoSub)

This method is used to subscribe to the discoverer.

discovererSendSubscription

protected DataObject discovererSendSubscription(Handler handler,
                                                DiscovererSubscriber discoSub)

to improve

discovererQuery

public java.util.Vector discovererQuery(AbstractQueryItem query)

This method allows to send a query to the discoverer.

Parameters:

query - The Query object containing the request for the discoverer

Returns:

ComponentDescription When the discoverer has found a context object corresponding to the request, the ComponentDescription object contains information about it, else it is null

See Also:

discovererQuery(DataObject)

discovererQuery

protected DataObject discovererQuery(DataObject data)

This method allows to send a query to the discoverer containing the description of the context component the object would like to know. It sends a DISCOVERER_QUERY message

Returns:

DataObject The result from the discoverer containing the first component description fitting the request

See Also:

Discoverer

discovererUnregistration

public Error discovererUnregistration()

This method allows to unregister from the discoverer

Returns:

Error The error message

See Also:

Discoverer

discovererSubscriptionNotification

public DataObject discovererSubscriptionNotification(DataObject data)

leaseEndNotified

protected DataObject leaseEndNotified(DataObject data)

This method sends a lease end confirmation if necessary.

Parameters:

data - The data object specifying the lease end

Returns:

DataObject The reply to the notification

getLease

public Lease getLease()

This method allows to specify a lease used to register the discoverer. Each time the component has to register or to renew its registration, it uses this lease. This method has to be overridden by inheriting classes. If not, it returns the default lease ??? : is it useful after all???

Returns:

Lease The specified lease

setLease

public void setLease(Lease lease)

Set the lease used to register the discoverer

activateDisplay

public void activateDisplay()

Activate the display

deactivateDisplay

public void deactivateDisplay()

Deactivate the display

setDisplay

public void setDisplay()

Create the display and activate it

setDisplay

public void setDisplay(GenericFrame frame)

setDisplayName

public void setDisplayName(java.lang.String objName)

Set the title displayed on the frame

setDisplayTitle

public void setDisplayTitle(java.lang.String title)

Set the title of the frame

println

public void println(java.lang.String s)

Print a string, on the displayed frame if it is activated or on the default output stream. Flushes the output stream

debugprintln

public static void debugprintln(boolean DEBUG_flag,
                                java.lang.Object s)

Print a message if the DEBUG mode is active

Parameters:

s - Any object, even null

setAllDebug

public void setAllDebug(boolean baseObjectDebug,
                        boolean communicationDebug,
                        boolean componentDebug)

Set the CTK classes in the DEBUG status