Objects, Components, and Frameworks with UML The Catalysis ...

© ICON Computing
Collaborations as Architectural Units
❒ A collaboration is an architectural package that contains:
• a set of related interacting types
• characterized by set of interfaces with behavior specifications
package patterns.SpellCheck;
interface SpellChecker {
void attach ( target: SpellCheckable);
void spellCheck ();
}
interface SpellCheckable {
Word nextWord ();
void replaceWord (replacement: Word);
}
© ICON Computing http://www.iconcomp.com
Collaboration
A collaboration is an architectural unit or package that contains a set of related interacting types, characterized by
the appropriate types (interfaces with behavior specifications).
This slide shows some Java code for the spell-checking collaboration (well, pseudo-Java).
The package,called patterns.SpellCheck simply to emphasize that this is a design pattern for implementing spell
checking in any application (and to set the stage for an upcoming discussion), contains two interfaces:
SpellChecker: any object playing this role must be able to attach to a target that provides the SpellCheckable
interface, and then to spellCheck that target.
SpellCheckable: any object playing this role must be able to provide sequential access to the words it contains,
and to replace the word at the current position in that sequence.
Note that this package is purely a design description. It contains no implementation code at all. If we wanted, we
could provide a default implementation class for each of these interfaces. We would most likely put this default
implementation into a separate package. A particular implementation could decide whether or not to use that default
implementation; if it did not, it could still implement this design pattern.
48
48