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strmod::strmod::StreamModule Class Reference

An abstract base for objects that can be modules in the StreamModule framework. More...

#include <StrMod/StreamModule.h>

Inheritance diagram for strmod::strmod::StreamModule:

[legend]List of all members.

Public Methods
	StreamModule ()
	Abstract class, doesn't do much.
virtual	~StreamModule ()
	Prudently virtual in an abstract base class.
virtual int	AreYouA (const lcore::ClassIdent &id) const
	Asks if a class is of a particular type, or publicly derived from that type.
virtual bool	canCreate (int side) const=0
	Can a plug be created on the given side?
Plug *	makePlug (int side)
	Attempts to create a plug on the given side.
virtual bool	ownsPlug (const Plug *plug) const=0
	Does the module own this plug?
virtual bool	deletePlug (Plug *plug)=0
	Please delete this plug.
PlugDisconnectStrategy *	getPDStrategy () const
	Get the current PlugDisconnectStrategy.
void	setPDStrategy (PlugDisconnectStrategy *pds)
	Set the current PlugDisconnectStrategy.
Static Public Attributes
const STR_ClassIdent	identifier
	A unique identifier for this class.
Protected Methods
virtual const lcore::ClassIdent *	i_GetIdent () const
	Returns the class identifier for the class the object actually is.
virtual void	plugDisconnected (Plug *plug)
	Called whenever a plug is disconnected.
virtual Plug *	i_MakePlug (int side)=0
	Makes a plug on the given side.
void	setReadableFlagFor (Plug *p, bool val)
	Used to set the readable flag of a plug since their set method is protected.
void	setWriteableFlagFor (Plug *p, bool val)
	Used to set the writeable flag of a plug since their set method is protected.
Friends
class	Plug

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Detailed Description

An abstract base for objects that can be modules in the StreamModule framework.

A StreamModule module can be thought of as a processing element in a stream of data. A StreamModule's 'sides' represent ports at which data can enter or leave the module.

If you were to think of the UNIX utility 'grep' as a StreamModule, it's 0 side would be stdin, and it's 1 side would be stdout. Depending on the implementation, it might also have a 2 side, where error messages are sent.

Of course, grep's 'sides' are not bi-directional, they are uni-directional. As a rule, a StreamModule's data port (a Plug) is bi-directional. One way to encapsulate a UNIX program designed to run in a pipeline would be to make a module that has a 0 side (stdin) a 1 side, with it either passing data unchanged in the reverse direction, or refusing to pass data in the reverse direction at all.

Another way would be to model it as a single sided StreamModule with it's input and output happening on the same plug. This would sort of violate the spirit of the StreamModule system though. There's currently only one module which operates this way, the EchoModule, which merely echoes all of its input to its output.

Definition at line 73 of file StreamModule.h.

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Member Function Documentation

int strmod::strmod::StreamModule::AreYouA (  const lcore::ClassIdent &    id )  const [inline, virtual]

Asks if a class is of a particular type, or publicly derived from that type. Overriden in every derived class (with a static identifier member) to compare against the identifier, then call the AreYouA methods of all the superclasses. Parameters: cid  Usually <class>::identifier for the class you want to ask if the object is an instance of. Reimplemented from strmod::lcore::Protocol. Reimplemented in strmod::strmod::EchoModule, strmod::strmod::InfiniteModule, strmod::strmod::ProcessorModule, strmod::strmod::RouterModule, strmod::strmod::SimpleMultiplexer, strmod::strmod::SimpleTelnetClient, strmod::strmod::SockListenModule, and strmod::strmod::StreamFDModule. Definition at line 391 of file StreamModule.h.

virtual bool strmod::strmod::StreamModule::deletePlug (  Plug *    plug )  [pure virtual]

Please delete this plug. Modules are supposed to own plugs, so you aren't supposed to delete them yourself. Returns false on failure. Failure could happen because module does not own the plug. Implemented in strmod::strmod::EchoModule, strmod::strmod::InfiniteModule, strmod::strmod::ProcessorModule, strmod::strmod::RouterModule, strmod::strmod::SimpleMultiplexer, strmod::strmod::SimpleTelnetClient, strmod::strmod::SockListenModule, strmod::strmod::StreamFDModule, and strmod::strmod::StreamSplitterModule.

StreamModule::PlugDisconnectStrategy * strmod::strmod::StreamModule::getPDStrategy (    )  const [inline]

Get the current PlugDisconnectStrategy. Deleting the object you get this way is a BAD thing unless you set a new strategy before you do it. Definition at line 408 of file StreamModule.h.

virtual const lcore::ClassIdent* strmod::strmod::StreamModule::i_GetIdent (    )  const [inline, protected, virtual]

Returns the class identifier for the class the object actually is. Should always be overridden in any class that has a static identifier member. Reimplemented from strmod::lcore::Protocol. Reimplemented in strmod::strmod::EchoModule, strmod::strmod::InfiniteModule, strmod::strmod::ProcessorModule, strmod::strmod::RouterModule, strmod::strmod::SimpleTelnetClient, strmod::strmod::SockListenModule, strmod::strmod::StreamFDModule, and strmod::strmod::StreamSplitterModule. Definition at line 158 of file StreamModule.h.

virtual Plug* strmod::strmod::StreamModule::i_MakePlug (  int    side )  [protected, pure virtual]

Makes a plug on the given side. Guaranteed to never be called if canCreate would return false. Must NEVER return 0 (NULL). Implemented in strmod::strmod::EchoModule, strmod::strmod::InfiniteModule, strmod::strmod::ProcessorModule, strmod::strmod::RouterModule, strmod::strmod::SimpleMultiplexer, strmod::strmod::SimpleTelnetClient, strmod::strmod::SockListenModule, strmod::strmod::StreamFDModule, and strmod::strmod::StreamSplitterModule.

StreamModule::Plug * strmod::strmod::StreamModule::makePlug (  int    side )  [inline]

Attempts to create a plug on the given side. When writing a derived class, your MakePlug function should ALWAYS call CanCreate first before calling i_MakePlug. Returns 0 (NULL) on failure. Only fails if CanCreate would return false. Reimplemented in strmod::strmod::EchoModule, strmod::strmod::InfiniteModule, and strmod::strmod::SockListenModule. Definition at line 396 of file StreamModule.h.

void strmod::strmod::StreamModule::plugDisconnected (  Plug *    plug )  [inline, protected, virtual]

Called whenever a plug is disconnected. This function isn't called when a plug is disconnected as a result of its destructor being called. This is used to provide a hook to do what you think you should do when a plug is disconnected. It calls the pdstrategy_ by default, if there is one. Reimplemented in strmod::strmod::EchoModule, strmod::strmod::SimpleMultiplexer, and strmod::strmod::StreamSplitterModule. Definition at line 418 of file StreamModule.h.

void strmod::strmod::StreamModule::setPDStrategy (  PlugDisconnectStrategy *    pds )  [inline]

Set the current PlugDisconnectStrategy. The StreamModule does not assume responsibility for deleting the object you pass in. Of course, if you delete it while the StreamModule has it set, that will probably cause bad things to happen. Setting the strategy to NULL essentially turns it off. Definition at line 413 of file StreamModule.h.

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

• StreamModule.h
• StreamModule.cxx

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