Component

A component is a rectangle with the component icon at its top right and its name inside. The simplest needs only a name.

component Scheduler

Names and aliases

A name with spaces needs quotes. Use as to give it a short alias for references.

component "Memory Allocator" as alloc
component "Page Table" as pages
alloc --> pages

Stereotypes

A stereotype goes in << and >>.

component "Orders DB" as db <<database>>
component "Billing API" as api <<external>>
api --> db

Nesting

Components can contain components. The outer one becomes a composite.

component "Network Stack" as net {
  component Socket
  component TCP
  component IP
  Socket --> TCP
  TCP --> IP
}

Nesting can go several levels deep.

component Kernel {
  component "I/O" as io {
    component VFS
    component Block
    VFS --> Block
  }
  component Memory
  io --> Memory
}

One-line blocks

A short body can share the line with its braces.

component Sensor { provides ISample }
component Logger { requires ISample }

Syntax

component <name> [as <alias>] [<<stereotype>>] [{ ... }]

UML 2.5.1, 11.6.4 (p. 210). A component is a classifier rectangle; showing the icon lets the «component» keyword be hidden, which drumlin does. In a composite the name is centred, with any keyword above it (9.2.4, p. 101).

Used in

Monolithic kernel, Storage engine, Compiler pipeline.

Keyboard shortcuts

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