Design Heuristics

Independent Filters

Heuristic

That filters must be independent entities: in particular, they should not share state with other filters. [1]

Heuristic

Filters should not know the identity of their upstream and downstream filters.

Heuristic

Specifications might restrict what appears on the input pipes or make guarantees about what appears on the output pipes, but they may not identify the components that are attached to the output pipes.

Single Responsible Filters

Heuristic

Filters should perform one task only. Composite tasks should be handled by a sequence of filters rather than a single one.

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References

1. Shaw, M., & Garlan, D. (1996). Software Architecture: Perspectives on an Emerging Discipline. Pearson.