Supporters providing extensible classes without recoding for object-oriented applications

A computer program product for adding support for contained classes to a container class, the computer program product including a computer readable medium and a computer mechanism stored thereon, the computer mechanism comprising:

• a first set of supporter classes, each of which provides first supporter methods for a first contained class;
• a second set of supporter classes, each of the second set providing second supporter methods for a second contained class;
• and
• an affinity class that configures a computer in whose memory a container class instance is allocated to:
• allocate in the memory an instance of the affinity class that manages instances of the second set of supporters for use by the container class instance to interact with instances of the second contained class using the second supporter methods;
• and
• add a new supporter instance for a particular contained class from the first set to the instances of the second set when a first method of the affinity class instance is invoked on an instance of the particular contained class whose supporter is in the first set and not the second set.