RWFactory(3C++)

Name
     RWFactory - Rogue Wave library class

Synopsis
              typedef unsigned short  RWClassID;



              typedef RWCollectable*  (*RWuserCreator)();
          #include <rw/factory.h>
          RWFactory* theFactory;




Description
     Class RWFactory can create an instance of an RWCollectable object, given
     a class ID.  It does this by maintaining a table of class IDs and
     associated "creator functions."  A creator function has prototype:

              RWCollectable*  aCreatorFunction();





     This function should create an instance of a particular class.  For a
     given RWClassID tag, the appropriate function is selected, invoked and
     the resultant pointer returned.  Because any object created this way is
     created off the heap, you are responsible for deleting it when done.
     There is a one-of-a-kind global RWFactory which can be accessed using
     getRWFactory.  It is guaranteed to have creator functions in it for all
     of the classes referenced by your program.  See also the section in the
     User's Guide about RWFactory.

Persistence
     None

Example
              #include <rw/factory.h>
          #include <rw/rwbag.h>
          #include <rw/colldate.h>
          #include <rw/rstream.h>
          main(){
           // Create new RWBag off the heap, using Class ID __RWBAG.
           RWBag* b = (RWBag*)getRWFactory ()->create(__RWBAG);
           b->insert( new RWCollectableDate ); // Insert today's date
           // ...
           b->clearAndDestroy();     // Cleanup: first delete members,
           delete b;                 // then the bag itself
          }

Public Constructors
              RWFactory();


     Construct an RWFactory.

Public  Operator
              RWBoolean
          operator<=(const RWFactory& h);


     Returns TRUE  if self is a subset of h, that is, every element of self
     has a counterpart in h which isEqual.  This operator is included to fix
     an inconsistency in the C++ language.  It is not explicitly present
     unless you are compiling with an implementation of the Standard C++
     Library.   It would normally be inherited from RWSet Note:  If you
     inherit from RWFactory in the presence of the Standard C++ Library, we
     recommend that you override this operator and explicitly forward the
     call.  Overload resolution in C++ will choose the Standard Library
     provided global operators over inherited class members.  These global
     definitions are not appropriate for set-like partial orderings.

Public Member Functions
              void
          addFunction(RWuserCreator uc, RWClassID id);


     Adds to the RWFactory the global function pointed to by uc, which creates
     an instance of an object with RWClassID id.

              void
          addFunction(RWuserCreator uc, RWClassID id, RWStringID sid);


     Adds to the RWFactory the global function pointed to by uc, which creates
     an instance of an object with RWClassID id and RWStringID sid.

              RWCollectable*
          create(RWClassID id) const;


     Allocates a new instance of the class with RWClassID id off the heap and
     returns a pointer to it.  Returns nil if id does not exist.  Because this
     instance is allocated off the heap, you are responsible for deleting it
     when done.

              RWCollectable*
          create(RWString sid) const;


     Allocates a new instance of the class with RWStringID sid off the heap
     and returns a pointer to it.  Returns nil if sid does not exist.  Because
     this instance is allocated off the heap, you are responsible for deleting
     it when done.

              RWuserCreator
          getFunction(RWClassID id) const;


     Returns from the RWFactory a pointer to the global function associated
     with RWClassID id.  Returns nil if id does not exist.

              RWuserCreator
          getFunction(RWStringID sid) const;


     Returns from the RWFactory a pointer to the global function associated
     with RWStringID sid.  Returns nil if sid does not exist.

              void
          removeFunction(RWClassID id);


     Removes from the RWFactory the global function associated with RWClassID
     id.  If id does not exist in the factory, no action is taken.

              void
          removeFunction(RWStringID sid);


     Removes from the RWFactory the global function associated with RWStringID
     sid.  If sid does not exist in the factory, no action is taken.

              RWStringID
          stringID(RWClassID id) const;


     Looks up the RWStringID associated with id and returns it.  If there is
     no such association, returns  RWStringID("NoID").

              RWClassID
          classID(RWStringID) const;


     Looks up the RWClassID associated with sid and returns it.  If there is
     no such association, returns __RWUNKNOWN.