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Population Interaction Unit
Problem
The system needs to show a set of homogeneus objects to the user.
Principle
Data presentation, data manipulation.
Forces
- Are the elements cohesive enough to present them as a set?
- The number of results to show to the user.
Solution
Select the class, the type the object belongs to.
Decide about the following considerations:
- What information should be presented for each object? Display Set
- The user needs to filter the set? Filter
- How information will be ordered? Sort Criteria
- What actions the user can perform over the set, or over individual objects? Actions
- What extra information can be offered related to the domain in this context? Navigation
Rationale
In a consistent way respect to Instance IU Population IU is an extension to work with collections of homogeneus data. Therefore, Display Set, Actions, & Navigation are shared as helper pattens by both Instance & Population IUs.
The addition of the collection aspect introduces new problems to deal with, more concretely: sorting and filtering.
Examples
Almost every example of grid's in business applications are samples of this pattern.
Specification
A Population IU pattern can be defined describing five aspects.
- A Display Set describes what information will be shown to the user for each object.
- Filter provides searching mechanism to reduce the size of the object's set been shown.
- Sort Criterium settles sorting methods to present the information in an intelligible form fot the task to be done.
- Actions will provide access to functionality related to this context.
- Navigation offers extra information related. The user can explore it if needed.
Representation
An Population Interaction Unit is represented by a wire frame box showing its name with a small grid in the upper-right corner.
