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TypeHandle Class Reference

TypeHandle is the identifier used to differentiate C++ class types. More...

#include <typeHandle.h>

List of all members.

Public Member Functions

 TypeHandle ()
 The default constructor must do nothing, because we can't guarantee ordering of static initializers.

 TypeHandle (const TypeHandle &copy)
bool operator== (const TypeHandle &other) const
bool operator!= (const TypeHandle &other) const
bool operator< (const TypeHandle &other) const
bool operator<= (const TypeHandle &other) const
bool operator> (const TypeHandle &other) const
bool operator>= (const TypeHandle &other) const
int compare_to (const TypeHandle &other) const
 Sorts TypeHandles arbitrarily (according to <, >, etc.).

string get_name (TypedObject *object=(TypedObject *) NULL) const
 Returns the name of the type.

bool is_derived_from (TypeHandle parent, TypedObject *object=(TypedObject *) NULL) const
 Returns true if this type is derived from the indicated type, false otherwise.

int get_num_parent_classes (TypedObject *object=(TypedObject *) NULL) const
 Returns the number of parent classes that this type is known to have.

TypeHandle get_parent_class (int index) const
 Returns the nth parent class of this type.

int get_num_child_classes (TypedObject *object=(TypedObject *) NULL) const
 Returns the number of child classes that this type is known to have.

TypeHandle get_child_class (int index) const
 Returns the nth child class of this type.

TypeHandle get_parent_towards (TypeHandle ancestor, TypedObject *object=(TypedObject *) NULL) const
 Returns the parent class that is in a direct line of inheritance to the indicated ancestor class.

int get_index () const
 Returns the integer index associated with this TypeHandle.

void output (ostream &out) const

Static Public Member Functions

TypeHandle none ()
 Returns a special zero-valued TypeHandle that is used to indicate no type.


Private Attributes

int _index

Static Private Attributes

TypeHandle _none

Friends

class TypeRegistry

Detailed Description

TypeHandle is the identifier used to differentiate C++ class types.

Any C++ classes that inherit from some base class, and must be differentiated at run time, should store a static TypeHandle object that can be queried through a static member function named get_class_type(). Most of the time, it is also desirable to inherit from TypedObject, which provides some virtual functions to return the TypeHandle for a particular instance.

At its essence, a TypeHandle is simply a unique identifier that is assigned by the TypeRegistry. The TypeRegistry stores a tree of TypeHandles, so that ancestry of a particular type may be queried, and the type name may be retrieved for run-time display.

Definition at line 111 of file typeHandle.h.

Constructor & Destructor Documentation

TypeHandle::TypeHandle (   )  [inline]
 

The default constructor must do nothing, because we can't guarantee ordering of static initializers.

If the constructor tried to initialize its value, it might happen after the value had already been set previously by another static initializer!

Definition at line 45 of file typeHandle.I.

TypeHandle::TypeHandle (  const TypeHandle &  copy  )  [inline]
 

Definition at line 56 of file typeHandle.I.

References _index, and INLINE.

Member Function Documentation

int TypeHandle::compare_to (  const TypeHandle &  other  )  const [inline]
 

Sorts TypeHandles arbitrarily (according to <, >, etc.).

Returns a number less than 0 if this type sorts before the other one, greater than zero if it sorts after, 0 if they are equivalent.

Definition at line 146 of file typeHandle.I.

References INLINE, TypeRegistry::is_derived_from(), and TypeRegistry::ptr().

TypeHandle TypeHandle::get_child_class (  int  index  )  const [inline]
 

Returns the nth child class of this type.

The index should be in the range 0 <= index < get_num_child_classes().

Definition at line 294 of file typeHandle.I.

int TypeHandle::get_index (   )  const [inline]
 

Returns the integer index associated with this TypeHandle.

Each different TypeHandle will have a different index. However, you probably shouldn't be using this method; you should just treat the TypeHandles as opaque classes. This is provided for the convenience of non-C++ scripting languages to build a hashtable of TypeHandles.

Definition at line 358 of file typeHandle.I.

Referenced by RenderState::Attribute::operator=(), RenderEffects::Effect::operator=(), TypedObject::operator=(), and TypeRegistry::write().

string TypeHandle::get_name (  TypedObject *  object = (TypedObject *)NULL  )  const [inline]
 

Returns the name of the type.

The "object" pointer is an optional pointer to the TypedObject class that owns this TypeHandle. It is only used in case the TypeHandle is inadvertantly undefined.

Definition at line 169 of file typeHandle.I.

References TypeRegistry::get_num_parent_classes(), INLINE, and TypeRegistry::ptr().

Referenced by TypedObject::get_type_index(), PartGroup::pick_channel_index(), and AnimGroup::write_datagram().

int TypeHandle::get_num_child_classes (  TypedObject *  object = (TypedObject *)NULL  )  const [inline]
 

Returns the number of child classes that this type is known to have.

This may then be used to index into get_child_class().

The "object" pointer is an optional pointer to the TypedObject class that owns this TypeHandle. It is only used in case the TypeHandle is inadvertantly undefined.

Definition at line 277 of file typeHandle.I.

int TypeHandle::get_num_parent_classes (  TypedObject *  object = (TypedObject *)NULL  )  const [inline]
 

Returns the number of parent classes that this type is known to have.

This may then be used to index into get_parent_class(). The result will be 0 if this class does not inherit from any other classes, 1 if normal, single inheritance is in effect, or greater than one if multiple inheritance is in effect.

The "object" pointer is an optional pointer to the TypedObject class that owns this TypeHandle. It is only used in case the TypeHandle is inadvertantly undefined.

Definition at line 233 of file typeHandle.I.

References TypeRegistry::get_parent_towards(), INLINE, and TypeRegistry::ptr().

TypeHandle TypeHandle::get_parent_class (  int  index  )  const [inline]
 

Returns the nth parent class of this type.

The index should be in the range 0 <= index < get_num_parent_classes().

Definition at line 250 of file typeHandle.I.

References _index, and INLINE.

TypeHandle TypeHandle::get_parent_towards (  TypeHandle  ancestor,
TypedObject *  object = (TypedObject *)NULL
)  const [inline]
 

Returns the parent class that is in a direct line of inheritance to the indicated ancestor class.

This is useful in the presence of multiple inheritance to try to determine what properties an unknown type may have.

The return value is TypeHandle::none() if the type does not inherit from the ancestor. If ancestor is the same as this type, the return value is this type.

The "object" pointer is an optional pointer to the TypedObject class that owns this TypeHandle. It is only used in case the TypeHandle is inadvertantly undefined.

Definition at line 333 of file typeHandle.I.

bool TypeHandle::is_derived_from (  TypeHandle  parent,
TypedObject *  object = (TypedObject *)NULL
)  const [inline]
 

Returns true if this type is derived from the indicated type, false otherwise.

The "object" pointer is an optional pointer to the TypedObject class that owns this TypeHandle. It is only used in case the TypeHandle is inadvertantly undefined.

Definition at line 198 of file typeHandle.I.

References TypeRegistry::get_num_child_classes(), INLINE, and TypeRegistry::ptr().

Referenced by FactoryBase::get_preferred(), and GraphicsPipeSelection::print_pipe_types().

TypeHandle TypeHandle::none (   )  [inline, static]
 

Returns a special zero-valued TypeHandle that is used to indicate no type.

Definition at line 386 of file typeHandle.I.

Referenced by AnimGroup::find_child(), FactoryBase::find_registered_type(), TypeRegistry::get_num_parent_classes(), FactoryBase::make_instance(), and operator>=().

bool TypeHandle::operator!= (  const TypeHandle &  other  )  const [inline]
 

Definition at line 79 of file typeHandle.I.

References _index, and INLINE.

bool TypeHandle::operator< (  const TypeHandle &  other  )  const [inline]
 

Definition at line 91 of file typeHandle.I.

References _index, and INLINE.

bool TypeHandle::operator<= (  const TypeHandle &  other  )  const [inline]
 

Definition at line 103 of file typeHandle.I.

References _index.

bool TypeHandle::operator== (  const TypeHandle &  other  )  const [inline]
 

Definition at line 67 of file typeHandle.I.

References _index, and INLINE.

bool TypeHandle::operator> (  const TypeHandle &  other  )  const [inline]
 

Definition at line 115 of file typeHandle.I.

References _index, and INLINE.

bool TypeHandle::operator>= (  const TypeHandle &  other  )  const [inline]
 

Definition at line 127 of file typeHandle.I.

References TypeRegistry::get_name(), INLINE, none(), and TypeRegistry::ptr().

void TypeHandle::output (  ostream &  out  )  const [inline]
 

Definition at line 371 of file typeHandle.I.

Friends And Related Function Documentation

friend class TypeRegistry [friend]
 

Definition at line 145 of file typeHandle.h.

Member Data Documentation

int TypeHandle::_index [private]
 

Definition at line 142 of file typeHandle.h.

Referenced by get_parent_class(), operator!=(), operator<(), operator<=(), operator==(), operator>(), TypeRegistry::ptr(), and TypeHandle().

TypeHandle TypeHandle::_none [static, private]
 

Definition at line 25 of file typeHandle.cxx.

The documentation for this class was generated from the following files:
Generated on Fri May 2 00:56:01 2003 for Panda by doxygen1.3