Component Diagram syntax and features

Component Diagram

Let's have few examples.

Components

Components must be bracketed.

You can also use the component keyword to define a component. And you can define an alias, using the as keyword. This alias will be used later, when defining relations.

@startuml

[First component]
[Another component] as Comp2
component Comp3
component [Last\ncomponent] as Comp4

@enduml

Interfaces

Interface can be defined using the () symbol (because this looks like a circle).

You can also use the interface keyword to define an interface. And you can define an alias, using the as keyword. This alias will be used latter, when defining relations.

We will see latter that interface definition is optional.

@startuml

() "First Interface"
() "Another interface" as Interf2
interface Interf3
interface "Last\ninterface" as Interf4

[component]
footer //Adding "component" to force diagram to be a **component diagram**//
@enduml

Basic example

Links between elements are made using combinations of dotted line (..), straight line (--), and arrows (-->) symbols.

@startuml

DataAccess - [First Component]
[First Component] ..> HTTP : use

@enduml

Using notes

You can use the note left of , note right of , note top of , note bottom of keywords to define notes related to a single object.

@startuml
[Component] as C

note top of C: A top note

note bottom of C
  A bottom note can also
  be on several lines
end note

note left of C
  A left note can also
  be on several lines
end note

note right of C: A right note
@enduml

A note can be also defined alone with the note keywords, then linked to other objects using the .. symbol or whatever arrow symbol (-, --, ...).

@startuml
[Component] as C

note as N
  A floating note can also
  be on several lines
end note

C .. N
@enduml

Another note example:

@startuml

interface "Data Access" as DA

DA - [First Component]
[First Component] ..> HTTP : use

note left of HTTP : Web Service only

note right of [First Component]
  A note can also
  be on several lines
end note

@enduml

Grouping Components

You can use several keywords to group components and interfaces together:

package
node
folder
frame
cloud
database

@startuml

package "Some Group" {
  HTTP - [First Component]
  [Another Component]
}

node "Other Groups" {
  FTP - [Second Component]
  [First Component] --> FTP
}

cloud {
  [Example 1]
}


database "MySql" {
  folder "This is my folder" {
    [Folder 3]
  }
  frame "Foo" {
    [Frame 4]
  }
}


[Another Component] --> [Example 1]
[Example 1] --> [Folder 3]
[Folder 3] --> [Frame 4]

@enduml

Changing arrows direction

By default, links between classes have two dashes -- and are vertically oriented. It is possible to use horizontal link by putting a single dash (or dot) like this:

@startuml
[Component] --> Interface1
[Component] -> Interface2
@enduml

You can also change directions by reversing the link:

@startuml
Interface1 <-- [Component]
Interface2 <- [Component]
@enduml

It is also possible to change arrow direction by adding left, right, up or down keywords inside the arrow:

@startuml
[Component] -left-> left
[Component] -right-> right
[Component] -up-> up
[Component] -down-> down
@enduml

You can shorten the arrow by using only the first character of the direction (for example, -d- instead of -down-) or the two first characters (-do-).

Please note that you should not abuse this functionality : Graphviz gives usually good results without tweaking.

And with the left to right direction parameter:

@startuml
left to right direction
[Component] -left-> left
[Component] -right-> right
[Component] -up-> up
[Component] -down-> down
@enduml

Use UML2 notation

By default (from v1.2020.13-14), UML2 notation is used.

@startuml

interface "Data Access" as DA

DA - [First Component]
[First Component] ..> HTTP : use

@enduml

Use UML1 notation

The skinparam componentStyle uml1 command is used to switch to UML1 notation.

@startuml
skinparam componentStyle uml1

interface "Data Access" as DA

DA - [First Component]
[First Component] ..> HTTP : use

@enduml

Use rectangle notation (remove UML notation)

The skinparam componentStyle rectangle command is used to switch to rectangle notation (without any UML notation).

@startuml
skinparam componentStyle rectangle

interface "Data Access" as DA

DA - [First Component]
[First Component] ..> HTTP : use

@enduml

Long description

It is possible to put description on several lines using square brackets.

@startuml
component comp1 [
This component
has a long comment
on several lines
]
@enduml

Individual colors

You can specify a color after component definition.

@startuml
component  [Web Server] #Yellow
@enduml

Using Sprite in Stereotype

You can use sprites within stereotype components.

@startuml
sprite $businessProcess [16x16/16] {
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFF0FFFFF
FFFFFFFFFF00FFFF
FF00000000000FFF
FF000000000000FF
FF00000000000FFF
FFFFFFFFFF00FFFF
FFFFFFFFFF0FFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
}


rectangle " End to End\nbusiness process" <<$businessProcess>> {
 rectangle "inner process 1" <<$businessProcess>> as src
 rectangle "inner process 2" <<$businessProcess>> as tgt
 src -> tgt
}
@enduml

Skinparam

You can use the skinparam command to change colors and fonts for the drawing.

You can use this command :

In the diagram definition, like any other commands;
In an included file;
In a configuration file, provided in the command line or the Ant task.

You can define specific color and fonts for stereotyped components and interfaces.

@startuml

skinparam interface {
  backgroundColor RosyBrown
  borderColor orange
}

skinparam component {
  FontSize 13
  BackgroundColor<<Apache>> Pink
  BorderColor<<Apache>> #FF6655
  FontName Courier
  BorderColor black
  BackgroundColor gold
  ArrowFontName Impact
  ArrowColor #FF6655
  ArrowFontColor #777777
}

() "Data Access" as DA
Component "Web Server" as WS << Apache >>

DA - [First Component]
[First Component] ..> () HTTP : use
HTTP - WS

@enduml

@startuml
[AA] <<static lib>>
[BB] <<shared lib>>
[CC] <<static lib>>

node node1
node node2 <<shared node>>
database Production

skinparam component {
    backgroundColor<<static lib>> DarkKhaki
    backgroundColor<<shared lib>> Green
}

skinparam node {
borderColor Green
backgroundColor Yellow
backgroundColor<<shared node>> Magenta
}
skinparam databaseBackgroundColor Aqua

@enduml

Specific SkinParameter

componentStyle

By default (or with skinparam componentStyle uml2), you have an icon for component

@startuml
skinparam BackgroundColor transparent
skinparam componentStyle uml2
component A {
   component "A.1" {
}
   component A.44 {
      [A4.1]
}
   component "A.2"
   [A.3]
   component A.5 [
A.5] 
   component A.6 [
]
}
[a]->[b]
@enduml

If you want to suppress it, and to have only the rectangle, you can use skinparam componentStyle rectangle

@startuml
skinparam BackgroundColor transparent
skinparam componentStyle rectangle
component A {
   component "A.1" {
}
   component A.44 {
      [A4.1]
}
   component "A.2"
   [A.3]
   component A.5 [
A.5] 
   component A.6 [
]
}
[a]->[b]
@enduml

[Ref. 10798]

Hide or Remove unlinked component

By default, all components are displayed:

@startuml
component C1
component C2
component C3
C1 -- C2
@enduml

But you can:

hide @unlinked components:

@startuml
component C1
component C2
component C3
C1 -- C2

hide @unlinked
@enduml

or remove @unlinked components:

@startuml
component C1
component C2
component C3
C1 -- C2

remove @unlinked
@enduml

[Ref. QA-11052]

Hide, Remove or Restore tagged component or wildcard

You can put $tags (using $) on components, then remove, hide or restore components either individually or by tags.

By default, all components are displayed:

@startuml
component C1 $tag13
component C2
component C3 $tag13
C1 -- C2
@enduml

But you can:

hide $tag13 components:

@startuml
component C1 $tag13
component C2
component C3 $tag13
C1 -- C2

hide $tag13
@enduml

or remove $tag13 components:

@startuml
component C1 $tag13
component C2
component C3 $tag13
C1 -- C2

remove $tag13
@enduml

or remove $tag13 and restore $tag1 components:

@startuml
component C1 $tag13 $tag1
component C2
component C3 $tag13
C1 -- C2

remove $tag13
restore $tag1
@enduml

or remove * and restore $tag1 components:

@startuml
component C1 $tag13 $tag1
component C2
component C3 $tag13
C1 -- C2

remove *
restore $tag1
@enduml

[Ref. QA-7337 and QA-11052]

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