In the data flow implementation, a channel is created by chaining ChannelElementBase objects. More...

#include <rtt/base/ChannelElementBase.hpp>

Inheritance diagram for RTT::base::ChannelElementBase:

Public Types
typedef boost::intrusive_ptr< ChannelElementBase >	shared_ptr

Public Member Functions
	ChannelElementBase ()
	A default constructed ChannelElementBase has no input nor output configured. More...

virtual	~ChannelElementBase ()

template<typename T >
ChannelElement< T > *	narrow ()
	Return a pointer to the typed variant of this ChannelElementBase. More...

shared_ptr	getInput ()
	Returns the current input channel element. More...

virtual shared_ptr	getInputEndPoint ()
	Returns the first input channel element of this connection. More...

shared_ptr	getOutput ()
	Returns the next channel element in the channel's propagation direction. More...

virtual shared_ptr	getOutputEndPoint ()
	Returns the last output channel element of this connection. More...

virtual bool	connectTo (ChannelElementBase::shared_ptr const &output, bool mandatory=true)
	Connects a new output to this element. More...

virtual bool	connectFrom (ChannelElementBase::shared_ptr const &input)
	Connects a new input to this element. More...

virtual bool	connected ()
	Returns true, if this channel element is connected on the input or output side. More...

virtual bool	signal ()
	Signals that there is new data available on this channel By default, the channel element forwards the call to its output. More...

virtual bool	signalFrom (ChannelElementBase *)
	Signals that there is new data available on this channel Forwards to signal() unless overwritten in a derived class. More...

virtual bool	channelReady (ChannelElementBase::shared_ptr const &caller, ConnPolicy const &policy, internal::ConnID *conn_id=0)
	This is called on the output half of a new connection by the connection factory in order to notify the output side of the new connection and check if it is ready to receive data. More...

virtual bool	inputReady (ChannelElementBase::shared_ptr const &caller)
	This is called by an input port when it is ready to receive data. More...

virtual void	clear ()
	Clears any data stored by the channel. More...

virtual void	disconnect (bool forward)
	Performs a disconnection of this channel's endpoints. More...

virtual bool	disconnect (ChannelElementBase::shared_ptr const &channel, bool forward)
	Performs a disconnection of a single input or output endpoint. More...

virtual PortInterface *	getPort () const
	Gets the port this channel element is connected to. More...

virtual const ConnPolicy *	getConnPolicy () const
	Get a pointer to the connection policy used to build this channel element, if available. More...

RTT_DEPRECATED void	setOutput (const ChannelElementBase::shared_ptr &output)

RTT_DEPRECATED void	setInput (const ChannelElementBase::shared_ptr &input)

virtual bool	isRemoteElement () const
	This function may be used to identify, if the current element uses a network transport, to send the data to the next Element in the logical chain. More...

virtual std::string	getRemoteURI () const
	This function returns the URI of the next channel element in the logical chain. More...

virtual std::string	getLocalURI () const
	This function return the URI of this element. More...

virtual std::string	getElementName () const
	Returns the class name of this element. More...

Static Public Member Functions
template<typename T >
static ChannelElement< T > *	narrow (ChannelElementBase *e)
	Return a pointer to the typed instance of a ChannelElementBase. More...

Protected Member Functions
void	ref ()
	Increases the reference count. More...

void	deref ()
	Decreases the reference count, and deletes the object if it is zero. More...

virtual bool	addOutput (shared_ptr const &output, bool mandatory=true)
	Sets the new output channel element of this element or adds a channel to the outputs list. More...

virtual void	removeOutput (shared_ptr const &output)
	Remove an output from the outputs list. More...

virtual bool	addInput (shared_ptr const &input)
	Sets the new input channel element of this element or adds a channel to the inputs list. More...

virtual void	removeInput (shared_ptr const &input)
	Remove an input from the inputs list. More...

Protected Attributes
shared_ptr	input

shared_ptr	output

RTT::os::SharedMutex	input_lock

RTT::os::SharedMutex	output_lock

Friends
class	MultipleInputsChannelElementBase

class	MultipleOutputsChannelElementBase

void RTT_API	intrusive_ptr_add_ref (ChannelElementBase *e)

void RTT_API	intrusive_ptr_release (ChannelElementBase *e)

Detailed Description

In the data flow implementation, a channel is created by chaining ChannelElementBase objects.

ChannelElementBase objects are refcounted. In the chain, an element maintains the refcount for its successor, and holds a simple pointer to its predecessor.

Definition at line 65 of file ChannelElementBase.hpp.

Member Typedef Documentation

typedef boost::intrusive_ptr<ChannelElementBase> RTT::base::ChannelElementBase::shared_ptr

Definition at line 68 of file ChannelElementBase.hpp.

Constructor & Destructor Documentation

ChannelElementBase::ChannelElementBase ( )

A default constructed ChannelElementBase has no input nor output configured.

The only way to set an input or output is to use connectTo() or connectFrom().

Definition at line 47 of file ChannelInterface.cpp.

References ORO_ATOMIC_SETUP().

ChannelElementBase::~ChannelElementBase ( )

virtual

Definition at line 52 of file ChannelInterface.cpp.

References ORO_ATOMIC_CLEANUP().

Member Function Documentation

bool ChannelElementBase::addInput ( shared_ptr const & input )

protectedvirtual

Sets the new input channel element of this element or adds a channel to the inputs list.

Parameters

input the previous element in chain.

Returns: true if the input was set or false if this element does not support multiple inputs and the input is already set.

Reimplemented in RTT::base::MultipleInputsChannelElementBase.

Definition at line 106 of file ChannelInterface.cpp.

References input, and input_lock.

Referenced by connectFrom().

bool ChannelElementBase::addOutput	(	shared_ptr const &	output,
		bool	mandatory = `true`
	)

protectedvirtual

Sets the new output channel element of this element or adds a channel to the outputs list.

Parameters

output	the next element in chain.
mandatory	whether the added output is mandatory for a write to succeed

Returns: true if the output was set or false if this element does not support multiple outputs and the output is already set.

Reimplemented in RTT::base::MultipleOutputsChannelElementBase.

Definition at line 79 of file ChannelInterface.cpp.

References output, and output_lock.

Referenced by connectTo().

bool ChannelElementBase::channelReady	(	ChannelElementBase::shared_ptr const &	caller,
		ConnPolicy const &	policy,
		internal::ConnID *	conn_id = `0`
	)

virtual

This is called on the output half of a new connection by the connection factory in order to notify the output side of the new connection and check if it is ready to receive data.

Each channel element has the responsibility to pass this notification on to the next, in the direction of the input. The ConnOutputEndPoint then calls back the inputReady() method in reverse direction to notify the output that the connection was successfully established.

Returns: false if a fatal connection failure was encountered and the channel needs to be destroyed.

Reimplemented in RTT::corba::RemoteChannelElement< T >, RTT::base::MultipleOutputsChannelElementBase, and RTT::internal::ConnOutputEndpoint< T >.

Definition at line 169 of file ChannelInterface.cpp.

References getInput(), getOutput(), input, inputReady(), and output.

Referenced by RTT::corba::RemoteChannelElement< T >::channelReady().

void ChannelElementBase::clear ( )

virtual

Clears any data stored by the channel.

It means that ChannelElement::read() will return false afterwards (provided that no new data has been written on the meantime of course)

By default, the channel element forwards the calls to its input

Reimplemented in RTT::base::MultipleInputsChannelElementBase, RTT::internal::SharedConnection< T >, RTT::internal::ChannelBufferElement< T >, and RTT::internal::ChannelDataElement< T >.

Definition at line 188 of file ChannelInterface.cpp.

References getInput(), and input.

Referenced by RTT::internal::ChannelDataElement< T >::clear(), RTT::internal::ChannelBufferElement< T >::clear(), and RTT::internal::SharedConnection< T >::clear().

bool ChannelElementBase::connected ( )

virtual

Returns true, if this channel element is connected on the input or output side.

Reimplemented in RTT::base::MultipleInputsMultipleOutputsChannelElementBase, RTT::base::MultipleOutputsChannelElementBase, and RTT::base::MultipleInputsChannelElementBase.

Definition at line 123 of file ChannelInterface.cpp.

References input, input_lock, output, and output_lock.

bool ChannelElementBase::connectFrom ( ChannelElementBase::shared_ptr const & input )

virtual

Connects a new input to this element.

Parameters

input the previous element in chain.

Definition at line 96 of file ChannelInterface.cpp.

References addInput(), and removeInput().

bool ChannelElementBase::connectTo	(	ChannelElementBase::shared_ptr const &	output,
		bool	mandatory = `true`
	)

virtual

Connects a new output to this element.

Parameters

output	the next element in chain.
mandatory	whether the added output is mandatory for a write operation to succeed

Definition at line 69 of file ChannelInterface.cpp.

References addOutput(), and removeOutput().

Referenced by RTT::internal::ConnFactory::buildChannelInput(), RTT::internal::ConnFactory::buildChannelOutput(), RTT::internal::ConnFactory::buildSharedConnection(), and RTT::internal::ConnFactory::createAndCheckSharedConnection().

void ChannelElementBase::deref ( )

protected

Decreases the reference count, and deletes the object if it is zero.

Definition at line 467 of file ChannelInterface.cpp.

References oro_atomic_dec_and_test().

Referenced by RTT::corba::RemoteChannelElement< T >::_remove_ref().

void ChannelElementBase::disconnect ( bool forward )

virtual

Performs a disconnection of this channel's endpoints.

If forward is true, then the disconnection is initiated by the input endpoint. Otherwise, it has been initiated by the output endpoint.

Definition at line 130 of file ChannelInterface.cpp.

References getInput(), getOutput(), input, output, removeInput(), and removeOutput().

Referenced by RTT::corba::RemoteChannelElement< T >::disconnect(), RTT::base::MultipleInputsChannelElementBase::disconnect(), RTT::base::MultipleOutputsChannelElementBase::disconnect(), RTT::internal::ConnectionManager::eraseConnection(), and RTT::corba::RemoteChannelElement< T >::remoteDisconnect().

virtual bool RTT::base::ChannelElementBase::disconnect	(	ChannelElementBase::shared_ptr const &	channel,
		bool	forward
	)

virtual

Performs a disconnection of a single input or output endpoint.

If forward is true, then the disconnection is initiated by the input endpoint and channel must be a connected input. Otherwise, it has been initiated by the output endpoint and channel must be a connected output. The disconnect call is only forwarded to the opposite side of the channel element after the last input/output element on either side has been removed.

The ChannelElementBase implementation ignores the given channel and disconnects unconditinally.

Reimplemented in RTT::base::MultipleInputsMultipleOutputsChannelElementBase, RTT::base::MultipleOutputsChannelElementBase, RTT::base::MultipleInputsChannelElementBase, RTT::corba::RemoteChannelElement< T >, RTT::internal::ConnOutputEndpoint< T >, and RTT::internal::ConnInputEndpoint< T >.

const ConnPolicy * ChannelElementBase::getConnPolicy ( ) const

virtual

Get a pointer to the connection policy used to build this channel element, if available.

This method will be overwritten for data and buffer elements.

Returns: null if there is no ConnPolicy associated with this element, a pointer to an instance of ConnPolicy otherwise.

Reimplemented in RTT::internal::ChannelBufferElement< T >, RTT::internal::ChannelDataElement< T >, and RTT::internal::SharedConnectionBase.

Definition at line 207 of file ChannelInterface.cpp.

Referenced by RTT::internal::ConnFactory::buildChannelInput(), and RTT::internal::ConnFactory::buildChannelOutput().

std::string ChannelElementBase::getElementName ( ) const

virtual

Returns the class name of this element.

This is primary useful for special case handling in the connection tracking.

Returns: The name of the class of the ChannelElement

Reimplemented in RTT::corba::RemoteChannelElement< T >, RTT::mqueue::MQChannelElement< T >, RTT::internal::ConnOutputEndpoint< T >, RTT::internal::ChannelBufferElement< T >, RTT::internal::ConnInputEndpoint< T >, and RTT::internal::ChannelDataElement< T >.

Definition at line 227 of file ChannelInterface.cpp.

ChannelElementBase::shared_ptr ChannelElementBase::getInput ( )

Returns the current input channel element.

This will only return a valid channel element if another element has received this object as an argument to connectTo().

Returns

Definition at line 57 of file ChannelInterface.cpp.

References input, and input_lock.

Referenced by channelReady(), clear(), disconnect(), RTT::base::ChannelElement< T >::getInput(), getInputEndPoint(), RTT::mqueue::MQChannelElement< T >::getLocalURI(), and RTT::corba::RemoteChannelElement< T >::getLocalURI().

ChannelElementBase::shared_ptr ChannelElementBase::getInputEndPoint ( )

virtual

Returns the first input channel element of this connection.

Will return the channel element the furthest away from the input port, or this if none.

Returns: getInput() ? getInput()->getInputEndPoint() : this

Reimplemented in RTT::internal::ConnInputEndpoint< T >.

Definition at line 157 of file ChannelInterface.cpp.

References getInput(), and input.

std::string ChannelElementBase::getLocalURI ( ) const

virtual

This function return the URI of this element.

The URI must be unique.

Returns: URI of this element.

Reimplemented in RTT::corba::RemoteChannelElement< T >, and RTT::mqueue::MQChannelElement< T >.

Definition at line 223 of file ChannelInterface.cpp.

Referenced by RTT::mqueue::MQChannelElement< T >::getLocalURI(), and RTT::corba::RemoteChannelElement< T >::getLocalURI().

ChannelElementBase::shared_ptr ChannelElementBase::getOutput ( )

Returns the next channel element in the channel's propagation direction.

Definition at line 63 of file ChannelInterface.cpp.

References output, and output_lock.

Referenced by channelReady(), disconnect(), RTT::base::ChannelElement< T >::getOutput(), getOutputEndPoint(), RTT::mqueue::MQChannelElement< T >::getRemoteURI(), RTT::corba::RemoteChannelElement< T >::getRemoteURI(), and signal().

ChannelElementBase::shared_ptr ChannelElementBase::getOutputEndPoint ( )

virtual

Returns the last output channel element of this connection.

Will return the channel element the furthest away from the output port, or this if none.

Returns: getOutput() ? getOutput()->getOutputEndPoint() : this

Reimplemented in RTT::internal::ConnOutputEndpoint< T >.

Definition at line 163 of file ChannelInterface.cpp.

References getOutput(), and output.

Referenced by RTT::corba::CDataFlowInterface_i::deregisterChannel().

PortInterface * ChannelElementBase::getPort ( ) const

virtual

Gets the port this channel element is connected to.

Returns: null if no port is connected to this element, the port (or a proxy representing the port) otherwise.

Reimplemented in RTT::internal::ConnOutputEndpoint< T >, and RTT::internal::ConnInputEndpoint< T >.

Definition at line 203 of file ChannelInterface.cpp.

std::string ChannelElementBase::getRemoteURI ( ) const

virtual

This function returns the URI of the next channel element in the logical chain.

The URI must be unique. E.g: In the local case output->getLocalURI() In the remote case the URI of the remote channel element.

Returns: URI of the next element.

Reimplemented in RTT::corba::RemoteChannelElement< T >, and RTT::mqueue::MQChannelElement< T >.

Definition at line 215 of file ChannelInterface.cpp.

References output.

Referenced by RTT::mqueue::MQChannelElement< T >::getRemoteURI(), and RTT::corba::RemoteChannelElement< T >::getRemoteURI().

virtual bool RTT::base::ChannelElementBase::inputReady ( ChannelElementBase::shared_ptr const & caller )

virtual

This is called by an input port when it is ready to receive data.

Each channel element has the responsibility to pass this notification on to the next, in the direction of the output.

Returns: false if a fatal connection failure was encountered and the channel needs to be destroyed.

Reimplemented in RTT::corba::RemoteChannelElement< T >, RTT::base::MultipleInputsChannelElementBase, RTT::mqueue::MQChannelElement< T >, and RTT::internal::ConnInputEndpoint< T >.

Referenced by channelReady().

bool ChannelElementBase::isRemoteElement ( ) const

virtual

This function may be used to identify, if the current element uses a network transport, to send the data to the next Element in the logical chain.

Returns: true if a network transport is used.

Reimplemented in RTT::corba::RemoteChannelElement< T >, and RTT::mqueue::MQChannelElement< T >.

Definition at line 211 of file ChannelInterface.cpp.

template<typename T >

static ChannelElement<T>* RTT::base::ChannelElementBase::narrow ( ChannelElementBase * e )

inlinestatic

Return a pointer to the typed instance of a ChannelElementBase.

Definition at line 101 of file ChannelElementBase.hpp.

Referenced by RTT::base::MultipleInputsChannelElement< T >::read().

template<typename T >

ChannelElement<T>* RTT::base::ChannelElementBase::narrow ( )

inline

Return a pointer to the typed variant of this ChannelElementBase.

Definition at line 109 of file ChannelElementBase.hpp.

void ChannelElementBase::ref ( )

protected

Increases the reference count.

Definition at line 462 of file ChannelInterface.cpp.

References oro_atomic_inc().

Referenced by RTT::corba::RemoteChannelElement< T >::_add_ref(), and RTT::corba::RemoteChannelElement< T >::RemoteChannelElement().

void ChannelElementBase::removeInput ( shared_ptr const & input )

protectedvirtual

Remove an input from the inputs list.

Parameters

input the element to be removed, or null to remove unconditionally

Reimplemented in RTT::base::MultipleInputsChannelElementBase, and RTT::base::MultipleInputsChannelElement< T >.

Definition at line 115 of file ChannelInterface.cpp.

References input_lock.

Referenced by connectFrom(), disconnect(), and RTT::base::MultipleInputsChannelElementBase::disconnect().

void ChannelElementBase::removeOutput ( shared_ptr const & output )

protectedvirtual

Remove an output from the outputs list.

Parameters

output the element to be removed, or null to remove unconditionally

Reimplemented in RTT::base::MultipleOutputsChannelElementBase.

Definition at line 88 of file ChannelInterface.cpp.

References output_lock.

Referenced by connectTo(), and disconnect().

RTT_DEPRECATED void RTT::base::ChannelElementBase::setInput ( const ChannelElementBase::shared_ptr & input )

inline

Definition at line 244 of file ChannelElementBase.hpp.

RTT_DEPRECATED void RTT::base::ChannelElementBase::setOutput ( const ChannelElementBase::shared_ptr & output )

inline

Definition at line 238 of file ChannelElementBase.hpp.

bool ChannelElementBase::signal ( )

virtual

Signals that there is new data available on this channel By default, the channel element forwards the call to its output.

Returns: false if an error occured that requires the channel to be invalidated. In no ways it indicates that the sample has been received by the other side of the channel.

Reimplemented in RTT::base::MultipleOutputsChannelElementBase, RTT::internal::ConnOutputEndpoint< T >, RTT::mqueue::MQChannelElement< T >, and RTT::corba::RemoteChannelElement< T >.

Definition at line 195 of file ChannelInterface.cpp.

References getOutput(), and output.

Referenced by RTT::corba::RemoteChannelElement< T >::remoteSignal(), RTT::corba::RemoteChannelElement< T >::signal(), RTT::base::MultipleOutputsChannelElementBase::signal(), RTT::base::MultipleInputsChannelElementBase::signalFrom(), and RTT::internal::ChannelDataElement< T >::write().

virtual bool RTT::base::ChannelElementBase::signalFrom ( ChannelElementBase * )

inlinevirtual

Signals that there is new data available on this channel Forwards to signal() unless overwritten in a derived class.

Reimplemented in RTT::base::MultipleInputsChannelElementBase.

Definition at line 173 of file ChannelElementBase.hpp.