Papyrus::DrawableWatcher Class Reference

DrawableWatcher is similar to DrawableMultiContainer except that it does not own the drawables it is watching. More...

#include <drawablewatcher.h>

Inheritance diagram for Papyrus::DrawableWatcher:

Public Types
typedef PapyrusPointer < DrawableWatcher >	pointer
typedef std::set < Drawable::weak_pointer, wp_lt_compare >	Watched
Public Member Functions
	DrawableWatcher ()
virtual	~DrawableWatcher ()
virtual bool	watch (Drawable::pointer item)
	Watches a particular drawable for changes.
virtual bool	remove_watch (Drawable::pointer item)
	Stops watching a particular drawable for changes.
virtual void	remove_all_watches ()
	Stops watching all drawables previously watched.
const Watched &	watched () const
	Returns the set of drawables being watched.
bool	is_watched (Drawable::pointer item)
	True if the specified drawable is being watched.
virtual void	link (DrawableSet::pointer s)
	Links this watcher to the drawable set causing the watcher to watch/remove watches as items are added to / removed from the set.
virtual void	unlink (DrawableSet::pointer s)
	Unlinks the watcher and the DrawableSet.
sigc::signal< void, Drawable::pointer > &	signal_watch_added ()
	Signal emitted when a drawable is watched.
sigc::signal< void, Drawable::pointer > &	signal_watch_removed ()
	Signal emitted when a drawable is no longer watched.
sigc::signal< void, Drawable::pointer > &	signal_watched_changed ()
	Signal emitted when a watched drawable emits the changed signal.
Protected Types
typedef std::map < Drawable::weak_pointer, sigc::connection, wp_lt_compare >	Connections
	Map from a drawable to a signal connection.
Protected Member Functions
virtual void	on_watched_changed (Drawable::pointer watched)
	Virtual method called when a watched child is changed.
Protected Attributes
Watched	m_watched
	The set of drawables being watched.
Connections	m_watched_changed_connections
Connections	m_watched_destroyed_connections
std::map< DrawableSet::pointer, sigc::connection >	m_linked_added_conn_map
std::map< DrawableSet::pointer, sigc::connection >	m_linked_removed_conn_map
sigc::signal< void, Drawable::pointer >	m_signal_watch_added
sigc::signal< void, Drawable::pointer >	m_signal_watch_removed
sigc::signal< void, Drawable::pointer >	m_signal_watched_changed
Private Member Functions
void	on_watched_changed_proxy (Drawable::weak_pointer watched)
	When a child is watched, this is the method connected to the child's changed signal which in turn calls on_watched_changed().
void	on_watched_destroyed (Drawable::weak_pointer watched)
	This method is connected to a child's destroyed signal causing automatic removal of the child.
void	on_linked_set_drawable_added (Drawable::pointer added)
void	on_linked_set_drawable_removed (Drawable::pointer removed)

Detailed Description

DrawableWatcher is similar to DrawableMultiContainer except that it does not own the drawables it is watching.

DrawableWatcher, unlike DrawableMultiContainer, uses weak smart pointers and thus does not take ownership of the items it is watching. Therefore, unless the item is owned by a group or some container other than the DrawableWatcher the drawable will be destroyed.

DrawableWatcher observes the destroyed signal of the drawables it is watching and removes them immediately upon destruction.

Since the container stores weak pointers, as a side note on weak vs. strong smart pointers; you can create a strong (owner) pointer from a weak (non-owning) pointer through the lock() method.

Author:: Rick L Vinyard Jr <rvinyard@cs.nmsu.edu>

Member Typedef Documentation

typedef std::map<Drawable::weak_pointer, sigc::connection, wp_lt_compare> Papyrus::DrawableWatcher::Connections [protected]

Map from a drawable to a signal connection.

typedef PapyrusPointer<DrawableWatcher> Papyrus::DrawableWatcher::pointer

typedef std::set<Drawable::weak_pointer, wp_lt_compare> Papyrus::DrawableWatcher::Watched

Constructor & Destructor Documentation

Papyrus::DrawableWatcher::DrawableWatcher ( )

Papyrus::DrawableWatcher::~DrawableWatcher ( ) [virtual]

Member Function Documentation

bool Papyrus::DrawableWatcher::is_watched ( Drawable::pointer item )

True if the specified drawable is being watched.

References m_watched.

void Papyrus::DrawableWatcher::link ( DrawableSet::pointer s ) [virtual]

Links this watcher to the drawable set causing the watcher to watch/remove watches as items are added to / removed from the set.

References m_linked_added_conn_map, m_linked_removed_conn_map, on_linked_set_drawable_added(), on_linked_set_drawable_removed(), and watch().

void Papyrus::DrawableWatcher::on_linked_set_drawable_added ( Drawable::pointer added ) [private]

References watch().

Referenced by link().

void Papyrus::DrawableWatcher::on_linked_set_drawable_removed ( Drawable::pointer removed ) [private]

References remove_watch().

Referenced by link().

void Papyrus::DrawableWatcher::on_watched_changed ( Drawable::pointer watched ) [protected, virtual]

Virtual method called when a watched child is changed.

When a watch is added, the watched item's changed signal is actually connected to the private proxy method, which in turn calls the virtual method. This allows children to implement their own behavior by reimplementing this method without worrying about modifying the add() or remove() methods.

Referenced by on_watched_changed_proxy().

void Papyrus::DrawableWatcher::on_watched_changed_proxy ( Drawable::weak_pointer watched ) [private]

When a child is watched, this is the method connected to the child's changed signal which in turn calls on_watched_changed().

References m_signal_watched_changed, and on_watched_changed().

Referenced by watch().

void Papyrus::DrawableWatcher::on_watched_destroyed ( Drawable::weak_pointer watched ) [private]

This method is connected to a child's destroyed signal causing automatic removal of the child.

References remove_watch().

Referenced by watch().

void Papyrus::DrawableWatcher::remove_all_watches ( ) [virtual]

Stops watching all drawables previously watched.

References m_signal_watch_removed, m_watched, m_watched_changed_connections, and m_watched_destroyed_connections.