Description

Base class for internal nodes that filter messages.

Filtering is applied when properties are baked, which should happen exactly once for each message, usually just before the message is posted for the first time.

Definition at line 723 of file Message.h.

#include <Sawyer/Message.h>

Inheritance diagram for Sawyer::Message::Filter:

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Collaboration diagram for Sawyer::Message::Filter:

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Public Member Functions
virtual void	bakeDestinations (const MesgProps &, BakedDestinations &)
	Bakes message properties according to the plumbing lattice.

virtual bool	shouldForward (const MesgProps &)=0
	Predicate determines when a message should be forwarded onward.

virtual void	forwarded (const MesgProps &)=0
	Called once by bakeDestinations if shouldForward() returned true.

Public Member Functions inherited from Sawyer::Message::Multiplexer
virtual void	post (const Mesg &, const MesgProps &)
	Causes a message to be emitted.

MultiplexerPtr	addDestination (const DestinationPtr &)
	Adds a child node to this node of the lattice.

MultiplexerPtr	removeDestination (const DestinationPtr &)
	Removes the specified child from this node of the lattice.

MultiplexerPtr	to (const DestinationPtr &)
	Add a child nodes to this node of the lattice and returns this node.

MultiplexerPtr	to (const DestinationPtr &, const DestinationPtr &)
	Add a child nodes to this node of the lattice and returns this node.

MultiplexerPtr	to (const DestinationPtr &, const DestinationPtr &, const DestinationPtr &)
	Add a child nodes to this node of the lattice and returns this node.

MultiplexerPtr	to (const DestinationPtr &, const DestinationPtr &, const DestinationPtr &, const DestinationPtr &)
	Add a child nodes to this node of the lattice and returns this node.

Public Member Functions inherited from Sawyer::Message::Destination
MesgProps	mergePropertiesNS (const MesgProps &props)
	Merge properties of this lattice node into the specified properties.

const MesgProps &	defaultPropertiesNS () const
	Default values for message properties.

MesgProps &	defaultPropertiesNS ()
	Default values for message properties.

const MesgProps &	overridePropertiesNS () const
	Overrides message properties.

MesgProps &	overridePropertiesNS ()
	Overrides message properties.

Public Member Functions inherited from Sawyer::SharedObject
	SharedObject ()
	Default constructor.

	SharedObject (const SharedObject &)
	Copy constructor.

virtual	~SharedObject ()
	Virtual destructor.

SharedObject &	operator= (const SharedObject &)
	Assignment.

Public Member Functions inherited from Sawyer::SharedFromThis< Destination >
SharedPointer< Destination >	sharedFromThis ()
	Create a shared pointer from `this`.

SharedPointer< const Destination >	sharedFromThis () const
	Create a shared pointer from `this`.

Protected Member Functions
	Filter ()
	Constructor for derived classes.

Protected Member Functions inherited from Sawyer::Message::Multiplexer
	Multiplexer ()
	Constructor for derived classes.

Additional Inherited Members
Static Public Member Functions inherited from Sawyer::Message::Multiplexer
static MultiplexerPtr	instance ()
	Allocating constructor.

Protected Attributes inherited from Sawyer::Message::Destination
Sawyer::SynchronizationTraits< Sawyer::SingleThreadedTag >::RecursiveMutex	mutex_
	Mutex protecting data members here and in subclasses.

MesgProps	dflts_
	Default properties merged into each incoming message.

MesgProps	overrides_
	Override properties applied to incoming message.

Constructor & Destructor Documentation

◆ Filter()

Sawyer::Message::Filter::Filter ( )

inlineprotected

Constructor for derived classes.

Non-subclass users should use instance instead.

Definition at line 726 of file Message.h.

Member Function Documentation

◆ bakeDestinations()

virtual void Sawyer::Message::Filter::bakeDestinations	(	const MesgProps &	,
		BakedDestinations &	baked
	)

virtual

Bakes message properties according to the plumbing lattice.

The given message properties are applied to the plumbing lattice rooted at this Destination, adjusted according to the default and override properties at this node of the lattice and all lower nodes. The property values at the bottom nodes of the lattice are appended to the baked argument.

Thread safety: All implementations must be thread-safe.

Reimplemented from Sawyer::Message::Multiplexer.

◆ shouldForward()

virtual bool Sawyer::Message::Filter::shouldForward ( const MesgProps & )

pure virtual

Predicate determines when a message should be forwarded onward.

This method is called once from bakeDestinations(), and if it returns true then the baking is forwarded on to the child nodes in the plumbing lattice. If this method returns false then none of the descendents will see the properties (unless they can be reached by some other path), and the unreached leaf nodes will not be returned by bakeDestinations().

Thread safety: all implementations must be thread-safe.

Implemented in Sawyer::Message::SequenceFilter, Sawyer::Message::TimeFilter, and Sawyer::Message::ImportanceFilter.