Since the publication of the Design Patterns book, a large number of object-oriented design patterns have been identified and codified. As part of the pattern form, objectoriented design patterns must indicate their relationships with other patterns, but these relationships are typically described very briefly, and different collections of patterns describe different relationships in different ways. In this paper we describe and classify the common relationships between object oriented design patterns. Practitioners can use these relationships to help them identity those patterns which may be applicable to a particular problem, and pattern writers can use these relationships to help them integrate new patterns into the body of the patterns literature. 1.

Since the publication of the Design Patterns book, a large number of design patterns have been identified and codified. Unfortunately, these patterns are mostly organised in an ad hoc fashion, making it hard for programmers to know which pattern to apply to any particular problem. We have organised a large number of existing object oriented design patterns into a pattern language, by analysing the patterns and the relationships between them. Organising patterns into languages has the potential to make large collections of patterns easier to understand and to use. 1: Introduction A object oriented design pattern is a "description of communicating objects and classes that are customised to solve a general design problem in a particular context" [12, p.3]. Designers can incorporate patterns into their programs to address general problems in the structure of their programs' designs. Before they can apply a pattern to solve their design problem, programmers must select an appropriate desig...

Since the publication of the Design Patterns book, a large number of design patterns have been identified and codified. Unfortunately, these patterns are mostly organised in an ad hoc fashion, making it hard for programmers to know which pattern to apply to any particular problem. We have organised a large number of existing object oriented design patterns into a pattern language, by analysing the patterns and the relationships between them. Organising patterns into languages has the potential to make large collections of patterns easier to understand and to use. 1

To design a program, first find your objects. Unfortunately, the right objects are not easy to find, and as a result most programs are not as well designed as they could be. This paper presents four patterns which describe how objects can be found within the designs of existing programs. By using these patterns, programs and designs can be made more simple, more general, and more easy to change. Introduction Finding objects is probably the most important part of object oriented design. The patterns in this paper describe one way to find objects --- by examining the design of the program. These patterns address two questions: how can you find objects within a program? and, once you have found some objects, what should you do with them? These patterns do not aim to describe novel research results; rather, they attempt to capture and present well known design techniques, illustrate when particular techniques are applicable, and outline their relative strengths and weaknesses. These patte...