ConnectionInterface Class Reference

#include <rtt/ConnectionInterface.hpp>

Inheritance diagram for ConnectionInterface:

List of all members.

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Detailed Description

An Object which manages and maintains a communication connection between Ports.

Creating a Connection

When connections are created, they are initially not connected, and hence, no port 'knows' of this connection object. In order to establish the connection between ports, call connect() explicitly on the newly created connection object. As long as that does not happen, it only keeps track of readers and writers, but does not connect them.

Connection Management

A connection object has two states: connected() or !connected(). In both states, any number of readers and writers may subscribe to this connection. If the state is !connected(), all subscribers will only be connected when the connect() method is called. If the state is connected(), every newly added subscriber is directly connected to the connection.

It is possible that a PortInterface participates in multiple 'dormant' (ie !connected()) connections while only one connection is connected() at the same time. If one tries to connect() a connection in which one ore more subscribers are already participating in the connection, the connect() method fails.

Reference counting

ConnectionInterface objects are reference counted. That means that if no object holds a pointer to this object, it will be destroyed. This can only happen if all ports disconnect from this connection.

Thread Safety

Although this interface may be implemented thread-safe, the DataConnection and BufferConnection classes have not been made thread-safe. This means that multiple threads calling connect()/disconnect() on the same or related connections may crash the system. Since connection setup is seen as an application configuration step, executed by a single configurator, Locking was not added. If this policy does not match your application setup, write your own ConnectionInterface subclass, or submit a bug report.

See also:

PortInterface

Definition at line 100 of file ConnectionInterface.hpp.

Public Types
typedef boost::intrusive_ptr < ConnectionInterface >	shared_ptr
Public Member Functions
	ConnectionInterface ()
virtual	~ConnectionInterface ()
virtual DataSourceBase::shared_ptr	getDataSource () const =0
	Get a Data source representing the current value of this connection.
virtual BufferBase::shared_ptr	getBuffer () const =0
	Returns the buffer and its associated status of this connection, if this connection is buffered.
virtual bool	connect ()=0
	Connect all readers and writers.
virtual bool	connected () const =0
	Get Connection status.
virtual bool	disconnect ()=0
	Disconnect all readers and writers.
virtual bool	addReader (PortInterface *r)=0
	Add a Port as possible reader (consumer) of the connection.
virtual bool	removeReader (PortInterface *r)=0
	Remove a Port as possible reader (consumer) of the connection.
virtual bool	addWriter (PortInterface *w)=0
	Add a Port as possible writer (producer) of the connection.
virtual bool	removeWriter (PortInterface *w)=0
	Remove a Port as possible writer (producer) of the connection.
Protected Member Functions
friend	void::intrusive_ptr_add_ref (ConnectionInterface *p)
friend	void::intrusive_ptr_release (ConnectionInterface *p)
Protected Attributes
oro_atomic_t	refcount

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Member Function Documentation

virtual DataSourceBase::shared_ptr getDataSource

(

)

const [pure virtual]

Get a Data source representing the current value of this connection.

This function always returns a meaningful data source.

Implemented in BufferConnection, and DataConnection.

virtual BufferBase::shared_ptr getBuffer

(

)

const [pure virtual]

Returns the buffer and its associated status of this connection, if this connection is buffered.

Otherwise, this returns the null pointer.

Implemented in BufferConnection, and DataConnection.

virtual bool connect

(

)

[pure virtual]

Connect all readers and writers.

If a reader or writer is already connected to another connection, this method fails.

Returns:

false if at least one reader or writer was already participating in a connection or if connected()

Implemented in BufferConnection, and DataConnection.

virtual bool addReader

(

PortInterface *

r

)

[pure virtual]

Add a Port as possible reader (consumer) of the connection.

If this->connected(), also immediately connect r to this connection.

Parameters:

r

A port which wants to read data from this connection.

Returns:

true if r has the correct type and could be added

Implemented in BufferConnection, and DataConnection.

Referenced by ConnectionFactory::createBuffer(), and ConnectionFactory::createDataObject().

virtual bool removeReader

(

PortInterface *

r

)

[pure virtual]

Remove a Port as possible reader (consumer) of the connection.

If this->connected(), also immediately disconnect r from this connection.

Parameters:

r

A port which no longer wants to read data from this connection.

Returns:

true if r was present.

Implemented in BufferConnection, and DataConnection.

virtual bool addWriter

(

PortInterface *

w

)

[pure virtual]

Add a Port as possible writer (producer) of the connection.

If this->connected(), also immediately connect w to this connection.

Parameters:

w

A port which wants to write data into this connection.

Returns:

true if w has the correct type and could be added.

Implemented in BufferConnection, and DataConnection.

Referenced by ConnectionFactory::createBuffer(), and ConnectionFactory::createDataObject().

virtual bool removeWriter

(

PortInterface *

w

)

[pure virtual]

Remove a Port as possible writer (producer) of the connection.

If this->connected(), also immediately disconnect w from this connection.

Parameters:

w

A port which no longer wants to write data into this connection.

Returns:

true if w was present.

Implemented in BufferConnection, and DataConnection.

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The documentation for this class was generated from the following files:

• rtt/ConnectionInterface.hpp
• rtt/ConnectionInterface.cpp

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