umlcomponentscomponent-diagram

UML Component symbol: Do the two blocks on the left represent something specific?

I have just received a diagram from a colleague, which I must now extend. It has numerous components, all of which are drawn using the following symbol.

enter image description here

I understand this is a "component" in UML component diagrams.

The diagram I've received has lines going out of the two blocks on the left to various other components, presumably to indicate a relationship with those other components.

Do the two blocks on the left have specific meanings? Is (for example) the top one input and the bottom one output? Or do they not have any specific meaning?

Solution

  • (1) According to Kirill Fakhroutdinov's explanation of the term Component in uml-diagrams.org: UML Component Diagrams this is an UML 1.4 notation which still can be used for backward compatibility reasons.

    Looking into the documents associated with UML Version 1.4 published by OMG back in 2001 you can find an example which clearly shows

    Source: http://www.omg.org/spec/UML/1.4/PDF/index.htm

    enter image description here

    Figure 3-94 Component Diagram

    that the two blocks originally did not have any specific meaning.

    (2) Similar notation with the meaning of input and output pin is used in UML activity diagrams, as shown in the picture below

    Source: Conrad Bock, UML 2 Activity and Action Models, Part 4: Object Nodes

    enter image description here

    Figure 14: Avoiding Deadlock

    (3) For your work of extending the legacy diagram you may find useful an uml-diagrams.org: UML component diagram example for online shopping