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Component Diagram Component Diagram (CPD)

Component Diagram (CPD)

The top-level Package Diagram (PD) in each UML model includes four packages: one for each of the views in the model. Two of these packages, called components and processes may be decomposed through one or more further levels of PD to a set of Component Diagrams (CPDs).

In the Component View, CPDs show dependencies between compilation units, typically including source files, and the runtime components of the final system. In the Process View, the CPDs show the dependencies between processes (scheduleable units that may be selected for execution on the host machine’s processor) in terms of runtime components. Runtime components typically include:

  • Executables
  • Dynamically linked libraries (DLLs)
  • Overlays
  • Shell scripts or batch files

These diagrams are intended to show the allocation of classes to compilation units and processes, respectively, although UML does not define how this is to occur. Cradle will support this mapping by providing a frame called CLASSES in which the names of the classes contained within the component or task can be listed.

By being defined in component specifications, the components and tasks are cross referenceable.

CPDs are not hierarchical. Their connectivity is:

Diagram showing the connectivity of a Component Diagram

CPDs are only available for models in the Implementation Domain.

Numbering of CPDs

CPDs take their name and number from the package from which they are an expansion. They contain components and tasks, each of which is defined by a specification.


An example CPD is:

Screenshot of a Component Diagram

Here is a description of the symbols available:

Symbol Name Description Definition Expansion


Comment Makes a note anywhere in the diagram. Are always surrounded by * characters. None None

Component Specification

Component Specification A software component, which may or may not be executable. Component specification None

Task Specification

Task Specification An executable component, typically known as a process, a thread, or a task. Component specification None

Component Dependency

Component Dependency A dependency between components. None None


Picture Allows you to choose the location of a GIF or JPEG image to be displayed as a diagram symbol or to be embedded in an existing diagram symbol. None None