Frameworks vs. Design Patterns

  At the first sight, it seems as if framework s were implemented design patterns. Even a careful analysis of the definitions of design pattern and framework does not help. A pattern is ``a recognisable way in which something is done, organised or happens'' [Procter95]. This definition certainly matches a framework. The definition of design pattern is too broad to be useful.

• The definition of pattern in the pattern community is based on the observation that there are reoccurring solution to reoccurring problems. Thus, the problem a pattern solves is just as much a part of the pattern as the arrangement of objects that makes up the solution. A pattern is, therefore, ``a solution to problem in a context'' [Johnson]. These patterns can not be easily expressed in object-oriented languages as we know them today.
• On the other side, a framework is more than a design pattern as it is also code. A framework is an abstract design expressed in abstract classes and, therefore, in code. A framework contains a model for the object interaction (collaborative model (see chapter )  ) and defines the kinds of classes. A framework will contain several design patterns as they are described in [GHJV95].
• So, both framework s and design pattern s are abstract designs to a given problem or problem family. But, design pattern s are much smaller and more abstract while framework s use design pattern s and are expressed in code.