OgreProperty.h File Reference

OGRE's property system allows you to associate values of arbitrary type with names, and have those values exposed via a self-describing interface. More...

#include "OgrePropertyPrerequisites.h"
#include "OgreAny.h"
#include "OgreIteratorWrappers.h"
#include "OgreString.h"
#include "OgreException.h"
#include "OgreQuaternion.h"
#include "OgreMatrix4.h"
#include <tr1/functional>

Classes
class	Ogre::Property< T >
	Property instance with passthrough calls to a given object. More...
class	Ogre::PropertyBase
	Base interface for an instance of a property. More...
class	Ogre::PropertyDef
	Definition of a property of an object. More...
class	Ogre::PropertySet
	Defines a complete set of properties for a single object instance. More...
struct	Ogre::PropertyValue
	A simple structure designed just as a holder of property values between the instances of objects they might target. More...

Namespaces
	Ogre
	This source file is part of OGRE (Object-oriented Graphics Rendering Engine) For the latest info, see http://www.ogre3d.org/

Typedefs
typedef GeneralAllocatedObject	Ogre::PropertyAlloc
typedef map< String, PropertyDef >::type	Ogre::PropertyDefMap
	Map from property name to shared definition. More...
typedef map< String, PropertyValue >::type	Ogre::PropertyValueMap
	Defines a transferable map of properties using wrapped value types (Ogre::Any) More...

Enumerations
enum	Ogre::PropertyType {   Ogre::PROP_SHORT = 0, Ogre::PROP_UNSIGNED_SHORT = 1, Ogre::PROP_INT = 2, Ogre::PROP_UNSIGNED_INT = 3,   Ogre::PROP_LONG = 4, Ogre::PROP_UNSIGNED_LONG = 5, Ogre::PROP_REAL = 6, Ogre::PROP_STRING = 7,   Ogre::PROP_VECTOR2 = 8, Ogre::PROP_VECTOR3 = 9, Ogre::PROP_VECTOR4 = 10, Ogre::PROP_COLOUR = 11,   Ogre::PROP_BOOL = 12, Ogre::PROP_QUATERNION = 13, Ogre::PROP_MATRIX3 = 14, Ogre::PROP_MATRIX4 = 15,   Ogre::PROP_UNKNOWN = 999 }
	The type of a property. More...

Detailed Description

OGRE's property system allows you to associate values of arbitrary type with names, and have those values exposed via a self-describing interface.

Unlike Ogre::StringInterface, the values are passed as their native types without needing conversion to or from strings; they are simply wrapped in an Ogre::Any and casts are performed to access them.

Property values are actually not stored in this system; instead the property definitions reference getter & setter methods which provide the 'backing' for the property. This means you can directly expose features of your classes as properties without any duplication.

There are two aspects to exposing a property on your class. One is exposing the definition of the property (PropertyDef), which should be shared between all instances and probably stored in a static PropertyDefMap somewhere. The second is the instance 'wiring' which ensures that a call to set a property calls a method on this particular instance of the class; this is formed by a number of Property instances, contained in a PropertySet. Each Property has an explicit binding to getter and setter instance methods.

So, here's an example of setting up properties on an instance:

// Make sure the property definition is created 
// propertyDefs is a variable of type PropertyDefMap, shared between instances
PropertyDefMap::iterator defi = propertyDefs.find("name");
if (defi == propertyDefs.end())
{
    defi = propertyDefs.insert(PropertyDefMap::value_type("name", 
        PropertyDef("name", 
            "The name of the object.", PROP_STRING))).first;
}
// This has established the property definition, and its description.
// Now, we need to 'wire' a property instance for this object instance
// We assume the class is called 'Foo' and the instance is pointed to by a variable called 'inst'
// 'props' is a PropertySet, specific to the instance
props.addProperty(
    OGRE_NEW Property<String>(&(defi->second),
        boost::bind(&Foo::getName, inst), 
        boost::bind(&Foo::setName, inst, _1)));