Component and Component and Deployment DiagramsDeployment Diagrams

Sources:

Agile Modeling

IBM’s Rational Library

Summary SlideSummary Slide

What is a Component Diagram Component Diagram Example in UML 1.4 Component Diagram Example in UML 2 Basic Notation Used in Component Diagrams Modeling a Component's Interfaces Interfaces and Ports Beyond the Basics What is a Deployment Diagram Deployment Diagram Example UML Deployment Diagram Example Concise UML 2 Deployment Diagram Network Diagrams

What is a Component DiagramWhat is a Component Diagram

The component diagram's main purpose is to show the structural relationships between the components of a system. [IBM Rational Libraries]

UML component diagrams are great for identifying the architectural landscape for your system as they enable you to model the high-level software components, and more importantly the interfaces to those components. [Agile Modeling]

Component Diagram ExampleComponent Diagram Example A component diagram provides a physical view of the system. Its purpose is to

show the dependencies that the software has on the other software components (e.g., software libraries) in the system. The diagram can be shown at a very high level, with just the large-grain components, or it can be shown at the component package level.

Modeling a component diagram is best described through an example. Figure below shows four components: Reporting Tool, Billboard Service, Servlet 2.2 API, and JDBC API. The arrowed lines from the Reporting Tool component to the Billboard Service, Servlet 2.2 API, and JDBC API components mean that the Reporting Tool is dependent on those three components.

Component Diagram Example in UML 1.4Component Diagram Example in UML 1.4

Component Diagram Example in UML 2Component Diagram Example in UML 2

Basic Notation Used in Component DiagramsBasic Notation Used in Component Diagrams Drawing a component in UML 2 is now very similar to drawing a class on a

class diagram. In fact, in UML 2 a component is merely a specialized version of the class concept. Which means that the notation rules that apply to the class classifier also apply to the component classifier.

In UML 2, a component is drawn as a rectangle with optional compartments stacked vertically. A high-level, abstracted view of a component in UML 2 can be modeled as just a rectangle with the component's name and the component stereotype text and/or icon. The component stereotype's text is «component»" and the component stereotype icon is a rectangle with two smaller rectangles protruding on its left side (the UML 1.4 notation element for a component).

When drawing a component on a diagram, it is important that you always include the component stereotype text (the word "component" inside double angle brackets, as shown in Figure below) and/or icon. The reason? In UML, a rectangle without any stereotype classifier is interpreted as a class element. The component stereotype and/or icon distinguishes this rectangle as a component element.

Modeling a Component's InterfacesModeling a Component's Interfaces UML 2 has also introduced another way to show a component's provided and

required interfaces. This second way builds off the single rectangle, with the component's name in it, and places what the UML 2 specification calls interface symbols" connected to the outside of the rectangle.

In this second approach the interface symbols with a complete circle at their end represent an interface that the component provides -- this lollipop" symbol is shorthand for a realization relationship of an interface classifier. Interface symbols with only a half circle at their end (a.k.a. sockets) represent an interface that the component requires (in both cases, the interface's name is placed near the interface symbol itself). For example, the Order component provides two interfaces: OrderEntry and AccountPayable, and the Order component requires the Person interface.

Interfaces and PortsInterfaces and Ports Components may both provide and require interfaces.  An interface is the

definition of a collection of one or more methods, and zero or more attributes, ideally one that defines a cohesive set of behaviors.  A provided interface is modeled using the lollipop notation and a required interface is modeled using the socket notation.  A port is a feature of a classifier that specifies a distinct interaction point between the classifier and its environment.  Ports are depicted as small squares on the sides of classifiers.

Ports can be named, such as the Security and Data ports on the Student component.

Ports can support unidirectional communication or bi-directional communication.  The Student component implements three ports, two unidirectional ports and one bi-directional ports.  The left-most port is an input port, the Security port is an output port, and the Data port is a bi-directional port.

Beyond the BasicsBeyond the Basics The component diagram is one of the easier-to-understand diagrams,

so there is not much to cover beyond the basics. There will be times when it makes sense to display a component's

internal structure. To show a component's inner structure, you merely draw the component larger than normal and place the inner parts inside the name compartment of the encompassing component. Figure below, show's the Store's component inner structure.

What is a Deployment DiagramWhat is a Deployment Diagram The deployment diagram shows how a system will be physically deployed in the

hardware environment. Its purpose is to show where the different components of the system will physically run and how they will communicate with each other. Since the diagram models the physical runtime, a system's production staff will make considerable use of this diagram.

The notation in a deployment diagram includes the notation elements used in a component diagram, with a couple of additions, including the concept of a node. A node represents either a physical machine or a virtual machine node (e.g., a mainframe node). To model a node, simply draw a three-dimensional cube with the name of the node at the top of the cube. Use the naming convention used in sequence diagrams.

Deployment Diagram ExampleDeployment Diagram ExampleThe deployment diagram below shows that the users access the Reporting Tool by using a browser running on their local machine and connecting via HTTP over their company's intranet to the Reporting Tool. This tool physically runs on the Application Server named w3reporting.myco.com. The diagram shows the Reporting Tool component drawn inside of IBM WebSphere, which in turn is drawn inside of the node w3.reporting.myco.com. The Reporting Tool connects to its reporting database using the Java language to IBM DB2's JDBC interface, which then communicates to the actual DB2 database running on the server named db1.myco.com using native DB2 communication. In addition to talking to the reporting database, the Report Tool component communicates via SOAP over HTTPS to the Billboard Service.

UML Deployment Diagram ExampleUML Deployment Diagram Example The three-dimensional boxes represent nodes, either software or hardware.  Physical

nodes should be labeled with the stereotype device, to indicate that it is a physical device such as a computer or switch. 

Connections between nodes are represented with simple lines, and are assigned

stereotypes such as RMI and message bus to indicate the type of connection.  

Concise UML 2 Deployment DiagramConcise UML 2 Deployment Diagram A better example is shown in the figure below. Software elements are now simply

listed by their physical filenames, information that developers are very likely to be interested in, and thus a more compact diagram is possible.  A drum is used as a visual stereotype for the University DB database, making it easier to distinguish on the diagram. Another difference is that the concise version shows less details, not as many tagged values are shown as this information can be captured in either

supporting documentation, configuration files, or source code. 

Network DiagramsNetwork Diagrams

Network diagrams are often drawn using software-based drawing tools (figure below was drawn using Microsoft Visio)

Summary SlideSummary Slide

What is a Component Diagram Component Diagram Example in UML 1.4 Component Diagram Example in UML 2 Basic Notation Used in Component Diagrams Modeling a Component's Interfaces Interfaces and Ports Beyond the Basics What is a Deployment Diagram Deployment Diagram Example UML Deployment Diagram Example Concise UML 2 Deployment Diagram Network Diagrams