Pattern : RELATIONSHIP TO OTHER PATTERNS

CONTEXT : You are writing the Related Patterns element of a pattern with Mandatory Elements Present.

PROBLEM : How do you make a pattern part of a larger group of patterns?

FORCES :

Few patterns are truly isolated; they usually lead to other patterns or they solve problems set up by other patterns.

Patterns are more useful if their relationships to other patterns are documented.

Determining and describing the related patterns can be hard work.

Too many references to patterns may distract the reader from the solution you are trying to describe.

It may be hard to find all the related patterns.

SOLUTION :

One of the key advantages of a pattern language over a standalone pattern is its ability to guide the reader to the solution of a complex problem by leading them from one pattern to another. Stand-alone patterns have to work harder to establish their relationships.

The pattern may have alternative patterns which solve the same problem in different ways.

The pattern description should point out similarities or differences from other patterns which might seem, on the surface, to be the same.

RATIONALE : Understanding the relationships between a pattern and other patterns makes a pattern more understandable and useful since alternative solutions can be assessed and follow-on patterns can be found and applied.