Object-stacking is a model for structuring object-based systems. The main feature of object-stacking is that layers of objects with a uniform interface are constructed, and the functions of these objects are integrated. In object-stacking, objects are classified into two types: bottom objects and stackable objects. Each bottom object provides a primitive function. Each stackable object provides a high-level function, such as filtering, indirection, caching, masking, or grouping. These functions are integrated by connecting several stackable objects and a bottom object.
Object-stacking is developed to implement high-level functions in file systems in a distributed operating system. The World Wide Web can be considered as an object-based file system. Therefore, object-stacking can be used in the Web for getting high-level functions.