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IDEA::MessageObserver Class Reference
[Agent handle classes]

This class is a base abstract class that allows the user to implement an observer on instances of MessageHandle. More...

#include <MessageObserver.hh>

Inheritance diagram for IDEA::MessageObserver:

List of all members.

Public Methods
virtual	~MessageObserver ()
	Destructor.
const std::string &	getName () const
	Returns the name of the invoking observer.
bool	hasPendingMessages ()
	Returns true if the invoking observer has pending messages in the queue.
int	getNrOfPendingMessages ()
	Returns the number of pending messages in the queue.
UpdatePolicy *	setUpdatePolicy (UpdatePolicy *policy, bool deleteInst=false)
	Sets the update-policy to policy and will delete the old one if it was constructed by the constructor of the invoking observer or if it was set with deleteInst true.
UpdatePolicy *	getUpdatePolicy () const
	Returns the current UpdatePolicy of the invoking observer.
AcceptorPolicy *	setAcceptorPolicy (AcceptorPolicy *policy, bool deleteInst=false)
	Sets the acceptor-policy to policy and will delete the old one if it was constructed by the constructor of the invoking observer or if it was set with deleteInst true.
AcceptorPolicy *	getAcceptorPolicy () const
	Returns the current AcceptorPolicy of the invoking observer.
virtual void	startUpdating ()
	Forces the invoking observer to start updating any of the messages in the queue using the UpdatePolicy of the invoking observer.
bool	isUpdating () const
	Returns true if the invoking observer is in the process of updating messages in the queue, otherwise returns false.
bool	isActive () const
	Returns true if the invoking observer is active otherwise false.
bool	updatesInSeperateThread () const
	Returns true if the invoking observer will update messages in a seperate thread. Otherwise returns false.
Protected Types
typedef ACE_Thread_Condition< ThreadMutex >	ConditionVariable
Protected Methods
	MessageObserver (const std::string &name="MessageObserver", bool threaded=false, long subscribeToMessages=Message::START|Message::STOP|Message::VALUE|Message::STATUS|Message::TELEMETRY|Message::OBJECT|Message::USERDEFINED)
	Constructor.
int	notify (MessageHandle message)
	Notifies the invoking observer that a message has been observed.
virtual int	activate ()
	Activates the invoking message-observer.
virtual void	deActivate ()
	De-activates the invoking message-observer.
virtual int	initialize ()
	Hook for additional setup, should return -1 in case of failed initialization.
void	updateInternal (const MessageHandle &message)
	Updates the message by checking type and extracting data and invoking the correct update method depending on the type.
virtual void	updateStartMessage (const Time &time, const StartMessageData *data)
	Invoked when a start-message is being updated.
virtual void	updateStopMessage (const Time &time, const StopMessageData *data)
	Invoked when a stop-message is being updated.
virtual void	updateValueMessage (const Time &time, const ValueMessageData *data)
	Invoked when a value-message is being updated.
virtual void	updateStatusMessage (const Time &time, const StatusMessageData *data)
	Invoked when a status-message is being updated.
virtual void	updateObjectMessage (const Time &time, const ObjectMessageData *data)
	Invoked when a object-message is being updated.
virtual void	updateTelemetryMessage (const Time &time, const TelemetryMessageData *data)
virtual void	updateUserDefinedMessage (const Time &time, const MessageData *data)
	Invoked when a user-defined-message is being updated.
virtual void	onQueueEmpty ()
	This method is invoked when the queue becomes empty. No signal is signalled at initialization (empty).
virtual void	onQueueNonEmpty ()
	This method is invoked when the queue becomes non-empty.
int	update ()
	Pops MessageHandle instance from the top of the queue and asks the UpdatePolicy if the message should be updated and if so will update based upon type of the message and release the handle when done.
int	svc (void)
	Main thred function used when invoking class has been constructed with threaded option true.
Protected Attributes
MessageHandleQueue	m_ObservedMessages
	A queue containing MessageHandle instance to be updated. The queue sorts the message conform the binary function latestTime (that is the top of the queue is the MessageHandle whose getTime is latest).
std::string	m_Name
	Name of the invoking observer.
UpdatePolicy *	m_UpdatePolicy
	Policy used for when to start updating and till what message in the queue.
bool	m_DeleteUpdatePolicy
	Indicating if the destructor of the invoking observer should delete the update-policy.
bool	m_Updating
	Indiates if the observer is updating messages.
bool	m_Active
	Indicates if the invoking observer is active.
bool	m_Threaded
	Boolean indicating if the messages will be udpated in a seperate thread.
ThreadMutex	m_Mutex
ConditionVariable *	m_StartCondition
	If the invoking class runs it's own thread to update the messages this variable is used to notify the thread to start updating.
AcceptorPolicy *	m_AcceptorPolicy
	Policy used for what message to accept to push in the queue.
bool	m_DeleteAcceptorPolicy
	Indicating if the destructor of the invoking observer should delete the acceptor-policy.
Friends
class	AgentRelay
class	ReactivePlanner

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Detailed Description

This class is a base abstract class that allows the user to implement an observer on instances of MessageHandle.

Author:

David Rijsman rijsman@email.arc.nasa.gov

The observer, MessageObserver, is invoked by a subject using API MessageObserver::notify( message ).

When the MessageObserver is notified it will invoke the UpdatePolicy associated with the invoked instance which will determine when the message(s) observed will be updated. When updated the message(s) will be filtered by type and the following (virtual) methods will be invoked:

• MessageObserver::updateStartMessage
• MessageObserver::updateStopMessage
• MessageObserver::updateValueMessage
• MessageObserver::updateStatusMessage
• MessageObserver::updateObjectMessage
• MessageObserver::updateTelemetryMessage
• MessageObserver::updateUserDefinedMessage

The MessageObserver has 'empty' implementation of these methods.

Warning:

After MessageObserver invoked any of the update messages mentioned above it will release the MessageHandle passed as parameter of these functions. This means you have to invoke MessageHandle::copy if you want the message to be around after invocation.

One can limit what messages will actually be stored on the queue when the MessageObserver is being notified in the constructor (see subscribeToMessages). This way the update will not be invoked for messages you have not subscribed to.

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Member Typedef Documentation

typedef ACE_Thread_Condition< ThreadMutex > IDEA::MessageObserver::ConditionVariable [protected]

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Constructor & Destructor Documentation

IDEA::MessageObserver::~MessageObserver (    )  [virtual]

Destructor.

IDEA::MessageObserver::MessageObserver (  const std::string &    name = "MessageObserver", bool    threaded = false, long    subscribeToMessages = Message::START|Message::STOP|Message::VALUE|Message::STATUS|Message::TELEMETRY|Message::OBJECT|Message::USERDEFINED )  [protected]

Constructor. Generates a MessageObserver with name name and will listen to messages subscribed to by using the flag subscribeToMessages. One can add or remove messages to the subscribtion by using the bitwise OR ( | ) operator on the following flags(enumeration): Message::START Message::STOP Message::VALUE Message::STATUS Message::TELEMETRY Message::OBJECT Message::USERDEFINED

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Member Function Documentation

int IDEA::MessageObserver::activate (    )  [protected, virtual]

Activates the invoking message-observer. release all the messages we did not update

void IDEA::MessageObserver::deActivate (    )  [protected, virtual]

De-activates the invoking message-observer.

AcceptorPolicy* IDEA::MessageObserver::getAcceptorPolicy (    )  const [inline]

Returns the current AcceptorPolicy of the invoking observer.

const std::string& IDEA::MessageObserver::getName (    )  const [inline]

Returns the name of the invoking observer.

int IDEA::MessageObserver::getNrOfPendingMessages (    )  [inline]

Returns the number of pending messages in the queue.

UpdatePolicy* IDEA::MessageObserver::getUpdatePolicy (    )  const [inline]

Returns the current UpdatePolicy of the invoking observer.

bool IDEA::MessageObserver::hasPendingMessages (    )

Returns true if the invoking observer has pending messages in the queue. Will take into account the logic of the UpdatePolicy, that is it will take the message at the top of the queue and check with the updatePolicy ( updateNextMessage( msg ) ) if it would be updated if we would invoke update. So there can be messages in the queue ( getNrOfPendingMessages() != 0 ) and this method returns false.

virtual int IDEA::MessageObserver::initialize (    )  [inline, protected, virtual]

Hook for additional setup, should return -1 in case of failed initialization. Reimplemented in IDEA::ReactivePlannerImpl, and IDEA::IPCRelay.

bool IDEA::MessageObserver::isActive (    )  const [inline]

Returns true if the invoking observer is active otherwise false.

bool IDEA::MessageObserver::isUpdating (    )

Returns true if the invoking observer is in the process of updating messages in the queue, otherwise returns false.

int IDEA::MessageObserver::notify (  MessageHandle    message )  [protected]

Notifies the invoking observer that a message has been observed.

virtual void IDEA::MessageObserver::onQueueEmpty (    )  [inline, protected, virtual]

This method is invoked when the queue becomes empty. No signal is signalled at initialization (empty).

virtual void IDEA::MessageObserver::onQueueNonEmpty (    )  [inline, protected, virtual]

This method is invoked when the queue becomes non-empty.

AcceptorPolicy * IDEA::MessageObserver::setAcceptorPolicy (  AcceptorPolicy *    policy, bool    deleteInst = false )

Sets the acceptor-policy to policy and will delete the old one if it was constructed by the constructor of the invoking observer or if it was set with deleteInst true. Returns the old acceptor-policy if it was not deleted otherwise 0. The acceptor-policy is used to decide to accept messages when the invoking class is notified. Be aware the new policy will override the message-types to accept passed in the constructor of the invoking class.

UpdatePolicy * IDEA::MessageObserver::setUpdatePolicy (  UpdatePolicy *    policy, bool    deleteInst = false )

Sets the update-policy to policy and will delete the old one if it was constructed by the constructor of the invoking observer or if it was set with deleteInst true. Returns the old update-policy if it was not deleted otherwise 0. The update-policy is used to trigger the updating of the messages.

void IDEA::MessageObserver::startUpdating (    )  [virtual]

Forces the invoking observer to start updating any of the messages in the queue using the UpdatePolicy of the invoking observer.

int IDEA::MessageObserver::svc (  void    )  [protected]

Main thred function used when invoking class has been constructed with threaded option true.

int IDEA::MessageObserver::update (    )  [protected]

Pops MessageHandle instance from the top of the queue and asks the UpdatePolicy if the message should be updated and if so will update based upon type of the message and release the handle when done. Returns -1 in case of an error.

void IDEA::MessageObserver::updateInternal (  const MessageHandle &    message )  [protected]

Updates the message by checking type and extracting data and invoking the correct update method depending on the type.

void IDEA::MessageObserver::updateObjectMessage (  const Time &    time, const ObjectMessageData *    data )  [protected, virtual]

Invoked when a object-message is being updated. To be implemented in the specialization. Reimplemented in IDEA::BoomerangRelay, IDEA::DefaultReactor, IDEA::SimulatorResponseScheduler, and IDEA::IPCRelay.

bool IDEA::MessageObserver::updatesInSeperateThread (    )  const [inline]

Returns true if the invoking observer will update messages in a seperate thread. Otherwise returns false.

void IDEA::MessageObserver::updateStartMessage (  const Time &    time, const StartMessageData *    data )  [protected, virtual]

Invoked when a start-message is being updated. To be implemented in the specialization. Reimplemented in IDEA::BoomerangRelay, IDEA::DefaultReactor, IDEA::ShutdownReactor, IDEA::SimulatorResponseScheduler, and IDEA::IPCRelay.

void IDEA::MessageObserver::updateStatusMessage (  const Time &    time, const StatusMessageData *    data )  [protected, virtual]

Invoked when a status-message is being updated. To be implemented in the specialization. Reimplemented in IDEA::BoomerangRelay, IDEA::DefaultReactor, IDEA::SimulatorResponseScheduler, and IDEA::IPCRelay.

void IDEA::MessageObserver::updateStopMessage (  const Time &    time, const StopMessageData *    data )  [protected, virtual]

Invoked when a stop-message is being updated. To be implemented in the specialization. Reimplemented in IDEA::BoomerangRelay, IDEA::DefaultReactor, IDEA::SimulatorResponseScheduler, and IDEA::IPCRelay.

void IDEA::MessageObserver::updateTelemetryMessage (  const Time &    time, const TelemetryMessageData *    data )  [protected, virtual]

Invoked when a telemetry-message is being updated. To be implemented in the specialization. Reimplemented in IDEA::BoomerangRelay, IDEA::DefaultReactor, and IDEA::IPCRelay.

void IDEA::MessageObserver::updateUserDefinedMessage (  const Time &    time, const MessageData *    data )  [protected, virtual]

Invoked when a user-defined-message is being updated. To be implemented in the specialization. Reimplemented in IDEA::BoomerangRelay, and IDEA::SimulatorResponseScheduler.

void IDEA::MessageObserver::updateValueMessage (  const Time &    time, const ValueMessageData *    data )  [protected, virtual]

Invoked when a value-message is being updated. To be implemented in the specialization. Reimplemented in IDEA::BoomerangRelay, IDEA::DefaultReactor, IDEA::SimulatorResponseScheduler, and IDEA::IPCRelay.

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Friends And Related Function Documentation

friend class AgentRelay [friend]

Reimplemented in IDEA::ComRelay, and IDEA::ShutdownReactor.

friend class ReactivePlanner [friend]

Reimplemented in IDEA::ReactivePlannerImpl.

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Member Data Documentation

AcceptorPolicy* IDEA::MessageObserver::m_AcceptorPolicy [protected]

Policy used for what message to accept to push in the queue.

bool IDEA::MessageObserver::m_Active [protected]

Indicates if the invoking observer is active.

bool IDEA::MessageObserver::m_DeleteAcceptorPolicy [protected]

Indicating if the destructor of the invoking observer should delete the acceptor-policy.

bool IDEA::MessageObserver::m_DeleteUpdatePolicy [protected]

Indicating if the destructor of the invoking observer should delete the update-policy.

ThreadMutex IDEA::MessageObserver::m_Mutex [protected]

std::string IDEA::MessageObserver::m_Name [protected]

Name of the invoking observer.

MessageHandleQueue IDEA::MessageObserver::m_ObservedMessages [protected]

A queue containing MessageHandle instance to be updated. The queue sorts the message conform the binary function latestTime (that is the top of the queue is the MessageHandle whose getTime is latest).

ConditionVariable* IDEA::MessageObserver::m_StartCondition [protected]

If the invoking class runs it's own thread to update the messages this variable is used to notify the thread to start updating.

bool IDEA::MessageObserver::m_Threaded [protected]

Boolean indicating if the messages will be udpated in a seperate thread.

UpdatePolicy* IDEA::MessageObserver::m_UpdatePolicy [protected]

Policy used for when to start updating and till what message in the queue.

bool IDEA::MessageObserver::m_Updating [protected]

Indiates if the observer is updating messages.

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