ime::Object Class Reference

An abstract base class for entities in IME. More...

#include <Object.h>

Inheritance diagram for ime::Object:

Public Types
using	Ptr = std::shared_ptr< Object >
	Shared object pointer. More...

Public Member Functions
	Object ()
	Default constructor. More...
	Object (const Object &)
	Copy constructor. More...
Object &	operator= (const Object &)
	Copy assignment operator. More...
	Object (Object &&) noexcept=default
	Move constructor. More...
Object &	operator= (Object &&) noexcept=default
	Move assignment operator. More...
void	setTag (const std::string &tag)
	Assign the object an alias. More...
const std::string &	getTag () const
	Get the alias of the object. More...
unsigned int	getObjectId () const
	Get the id of the object. More...
virtual std::string	getClassName () const =0
	Get the name of the concrete class. More...
virtual std::string	getClassType () const
	Get the name of the direct parent of an object instance. More...
int	onPropertyChange (const std::string &property, const Callback< Property > &callback)
	Add an event listener to a specific property change event. More...
void	onPropertyChange (const Callback< Property > &callback)
	Add an event listener to a property change event. More...
int	onEvent (const std::string &event, const Callback<> &callback)
	Add an event listener to an event. More...
bool	unsubscribe (const std::string &event, int id)
	Remove an event listener from an event. More...
int	onDestruction (const Callback<> &callback)
	Add a destruction listener. More...
bool	removeDestructionListener (int id)
	Remove a destruction listener form the object. More...
bool	operator== (const Object &rhs) const
	Check if two objects are the same object or not. More...
bool	operator!= (const Object &rhs) const
	Check if two objects are not the same object. More...
virtual	~Object ()
	Destructor. More...

Protected Member Functions
void	emitChange (const Property &property)
	Dispatch a property change event. More...
void	emit (const std::string &event)
	Dispatch an action event. More...

Detailed Description

An abstract base class for entities in IME.

Note that some entities are standalone and do not inherit from this class

Definition at line 43 of file Object.h.

Member Typedef Documentation

Ptr

using ime::Object::Ptr = std::shared_ptr<Object>

Shared object pointer.

Definition at line 45 of file Object.h.

Constructor & Destructor Documentation

Object() [1/3]

ime::Object::Object

(

)

Default constructor.

Object() [2/3]

ime::Object::Object

(

const Object &

)

Copy constructor.

Object() [3/3]

ime::Object::Object ( Object &&  )

defaultnoexcept

Move constructor.

~Object()

virtual ime::Object::~Object ( )

virtual

Destructor.

Member Function Documentation

emit()

void ime::Object::emit ( const std::string &  event )

protected

Dispatch an action event.

Parameters

event

The name of the event to be dispatched

This function will invoke all event listeners of the specified event. The function should be used for events that represent an action, rather than those that represent a property change (Use emitChange for that)

See also

emitChange

emitChange()

void ime::Object::emitChange ( const Property &  property )

protected

Dispatch a property change event.

Parameters

property

The property that changed

This function will invoke all the event listeners of the specified property

See also

emit

getClassName()

virtual std::string ime::Object::getClassName ( ) const

pure virtual

Get the name of the concrete class.

Returns

The name of the objects concrete class

This function is implemented by all internal classes that inherit from this class.

See also

getClassType

Implemented in ime::Tile, ime::SpriteSheet, ime::Sprite, ime::RectangleShape, ime::ConvexShape, ime::CircleShape, ime::Camera, ime::Scene, ime::RenderLayerContainer, ime::RenderLayer, ime::TargetGridMover, ime::RandomGridMover, ime::KeyboardGridMover, ime::DistanceJoint, ime::PolygonCollider, ime::EdgeCollider, ime::CircleCollider, ime::BoxCollider, ime::Body, ime::AABB, and ime::GameObject.

getClassType()

virtual std::string ime::Object::getClassType ( ) const

virtual

Get the name of the direct parent of an object instance.

Returns

The name of the direct parent of an object instance

In contrast to getClassName which returns the name of the concrete class, this function returns the name of the concrete class's base class. This function is implemented by all derived classes of Object which also serve as base classes for other Objects. For classes whose direct parent is this class, this function will return the name of this class

auto rectangle = ime::RectangleShape(); // RectangleShape is derived from Shape
std::cout << rectangle->getClassName(); // Prints "RectangleShape"
std::cout << rectangle->getClassType(); // Prints "Shape"

See also

getClassName

Reimplemented in ime::SpriteImage, ime::Shape, ime::Drawable, ime::GridMover, ime::Joint, ime::Collider, and ime::GameObject.

getObjectId()

unsigned int ime::Object::getObjectId

(

)

const

Get the id of the object.

Returns

The id of the object

Each object has a unique id

getTag()

const std::string& ime::Object::getTag

(

)

const

Get the alias of the object.

Returns

The alias of the object

See also

setTag and getObjectId

onDestruction()

int ime::Object::onDestruction

(

const Callback<> &

callback

)

Add a destruction listener.

Parameters

callback

Function to be executed when the object is destroyed

Returns

The id of the destruction listener

Note that an object may have more than one destruction listeners, however, you have to keep the returned id if you may want to remove the callback at a later time

Warning

The callback is called when the object is destroyed. Do not try to access the object in the callback. Doing so is undefined behavior

See also

removeDestructionListener

onEvent()

int ime::Object::onEvent	(	const std::string &	event,
		const Callback<> &	callback
	)

Add an event listener to an event.

Parameters

event	The name of the event to add an an event listener to
callback	The function to be executed when the event takes place

Returns

The unique identification number of the event listener

Unlike onPropertyChange, this function registers event listeners to events that occur when something happens to the object, or when the object does something (action events). Usually the name of the event/action is the name of the function:

// Add event listeners to the object
object.onEvent("attachRigidBody", [] {
    std::cout << "Rigid body attached to object << std::endl;
});
 
object.onEvent("removeRigidBody", [] {
    std::cout << "Rigid body removed from object << std::endl;
});
 
// Invokes event listener(s)
object.attachRigidBody(body);
object.removeRigidBody();

See also

onPropertyChange and unsubscribe

onPropertyChange() [1/2]

void ime::Object::onPropertyChange

(

const Callback< Property > &

callback

)

Add an event listener to a property change event.

Parameters

callback

The function to be executed when the property changes

Returns

The unique id of the event listener

Note that only one callback function may be registered with this function. This means that adding a new event listener overwrites the previous event listener. To remove the callback, pass a nullptr as an argument. The function may be useful if you want to write the logic for property changes in one function.

See also

onPropertyChange(std::string, Callback)

onPropertyChange() [2/2]

int ime::Object::onPropertyChange	(	const std::string &	property,
		const Callback< Property > &	callback
	)

Add an event listener to a specific property change event.

Parameters

property	The name of the property to listen for
callback	The function to be executed when the property changes

Returns

The unique id of the event listener

A property change event is triggered by any function that begins with set, where the the text after set is the name of the property. For example, for the setTag function, the property that the function modifies is Tag.

Note that when adding a property change event listener, the name of the property must be in lowercase:

// Prints the tag of the player object to the console everytime it changes
player.onPropertyChange("tag", [](const Property& property) {
     cout << "New tag: " <<  property.getValue<std::string>() << endl;
});
 
...
//Sets tag = "player1" and invokes event listener(s)
player.setTag("player1");

Unlike onPropertyChange(const Callback&) you can add multiple event listeners to the same property using this function. However you must store the unique id of the event listener if you wish to remove it at a later time

See also

unsubscribe and onPropertyChange(Callback)

operator!=()

bool ime::Object::operator!=

(

const Object &

rhs

)

const

Check if two objects are not the same object.

Parameters

rhs	Object to compare against this object

Returns

True if rhs is NOT the same object as this object, otherwise false

Two objects are different from each other if they have different object id's

See also

getObjectId and operator==

operator=() [1/2]

Object& ime::Object::operator=

(

const Object &

)

Copy assignment operator.

operator=() [2/2]

Object& ime::Object::operator= ( Object &&  )

defaultnoexcept

Move assignment operator.

operator==()

bool ime::Object::operator==

(

const Object &

rhs

)

const

Check if two objects are the same object or not.

Parameters

rhs	Object to compare against this object

Returns

True if rhs is the same object as this object, otherwise false

Two objects are the same object if they have the same object id. Recall that each object instance has a unique id

See also

getObjectId and operator!=

removeDestructionListener()

bool ime::Object::removeDestructionListener

(

int

id

)

Remove a destruction listener form the object.

Parameters

The	id of the destruction listener to be removed

Returns

True if the destruction listener was removed or false if the listener with the given id does not exist

setTag()

void ime::Object::setTag

(

const std::string &

tag

)

Assign the object an alias.

Parameters

name	The alias of the object

This function is useful if you want to refer to the object by tag instead of its id. Unlike an object id, multiple objects may have the same tag.

By default, the tag is an empty string

unsubscribe()

bool ime::Object::unsubscribe	(	const std::string &	event,
		int	id
	)

Remove an event listener from an event.

Parameters

event	The name of the event to remove event listener from
id	The unique id of the event listener to be removed

Returns

True if the event listener was removed or false if the event or the event listener is does not exist

// Display the name of the object to console every time it changes
auto nameChangeId = object.onPropertyChange("name", [](Property name) {
     std::cout << name.getValue<std::string>() << std::endl;
});
 
// Stop displaying the name of the object when it changes
object.unsubscribe("name", id);

---

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

• Object.h