# Class Diagram

![Class Diagram](https://135672590-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-L9shwSMiocGHpSKcbss%2F-MICRkvtgCev38ZdEOzz%2F-MICXxhUZPR6Q1UWMdUN%2FClass%20Diagram!UML%20Property_6.png?alt=media\&token=cc7829d2-8dac-45fa-a4c9-00745fd212f8)

## Create Class Diagram

To create a Class Diagram:

1. First select an element where a new Class Diagram to be contained as a child.
2. Select **Model | Add Diagram | Class Diagram** in the Menu Bar or select **Add Diagram | Class Diagram** in Context Menu.

> **See also**
>
> [UML Class Diagram](http://www.uml-diagrams.org/class-diagrams-overview.html) - For more information about UML Class Diagram.

## Model Element

Model Element is an abstract element of all UML model elements.

You can use **QuickEdit** for Model Element by double-click or press `Enter` on a selected model element.

* **Name Expression** : Edit name expression.

  *Syntax of Name Expression*

  ```
  expression ::= [ '<<' stereotype `>>` ] [ visibility ] name
  stereotype ::= (identifier)
  visibility ::= '+' | '#' | '-' | '~'
  name ::= (identifier)
  ```
* **Visibility** : Change visibility property.
* **Add Note** : Add a linked note.
* **Add Constraint** : Add a constraint.

## Classifier

Classifier is an abstract element of:

* [Class](#class)
* [Interface](#interface)
* [Signal](#signal)
* [DataType](#datatype)
* [PrimitiveType](#primitivetype)
* [Enumeration](#enumeration)
* [Component](https://docs.staruml.io/master/component-diagram#component)
* [Artifact](https://docs.staruml.io/master/component-diagram#artifact)

You can use **QuickEdit** for Classifier by double-click or press `Enter` on a selected classifier.

* **Name Expression** : Edit name expression.

  *Syntax of Name Expression*

  ```
  expression ::= [ '<<' stereotype `>>` ] [ visibility ] name
  stereotype ::= (identifier)
  visibility ::= '+' | '#' | '-' | '~'
  name ::= (identifier)
  ```
* **Visibility** : Change visibility property.
* **Add Note** : Add a linked note.
* **Add Constraint** : Add a constraint.
* **Add Attribute** (`Ctrl+Enter`) : Add an attribute.
* **Add Operation** (`Ctrl+Shift+Enter`) : Add an operation.
* **Add Reception** : Add a reception.

## Class

To create a Class:

1. Select **Class** in **Toolbox**.
2. Drag on the diagram as the size of Class.

To create a Class (model element only) by Menu:

1. Select an Element where a new Class to be contained.
2. Select **Model | Add | Class** in Menu Bar or **Add | Class** in Context Menu.

You can use **QuickEdit** for Class by double-click or press `Enter` on a selected Class.

* **Name Expression** : Edit name expression.

  *Syntax of Name Expression*

  ```
  expression ::= [ '<<' stereotype `>>` ] [ visibility ] name
  stereotype ::= (identifier)
  visibility ::= '+' | '#' | '-' | '~'
  name ::= (identifier)
  ```
* **Visibility** : Change visibility property.
* **Add Note** : Add a linked note.
* **Add Constraint** : Add a constraint.
* **Add Attribute** (`Ctrl+Enter`) : Add an attribute.
* **Add Operation** (`Ctrl+Shift+Enter`) : Add an operation.
* **Add Template Parameter** : Add a template parameter.
* **Add Reception** : Add a reception.
* **Add Sub-Class** : Add a sub-class.
* **Add Super-Class** : Add a super class.
* **Add Provided Interface** : Add a provided interface.
* **Add Required Interface** : Add a required interface.
* **Add Associated Class** : Add an associated class.
* **Add Aggregated Class** : Add an aggregated class.
* **Add Composited Class** : Add a composited class.
* **Add Port** : Add a port.
* **Add Part** : Add a part.

To suppress Attributes, see [Suppress Attributes](https://docs.staruml.io/master/user-guide/formatting-diagram#suppress-attributes).

To suppress Operations, see [Suppress Operations](https://docs.staruml.io/master/user-guide/formatting-diagram#suppress-operations).

To suppress Receptions, see [Suppress Receptions](https://docs.staruml.io/master/user-guide/formatting-diagram#suppress-receptions).

To show or hide Operation Signatures, see [Show Operation Signature](https://docs.staruml.io/master/user-guide/formatting-diagram#show-operation-signature).

## Attribute

To add an Attribute:

1. Select a Classifier.
2. Select **Model | Add | Attribute** in Menu Bar or **Add | Attribute** in Context Menu.

You can use **QuickEdit** for Attribute by double-click or press `Enter` on a selected Attribute.

* **Attribute Expression** : Edit Attribute expression.

  *Syntax of Attribute Expression*

  ```
  attribute ::= [ '<<' stereotype `>>` ] [ visibility ] name [':' type ] [ '[' multiplicity ']' ] [ '=' defaut-value ]
  stereotype ::= (identifier)
  visibility ::= '+' | '#' | '-' | '~'
  name ::= (identifier)
  type ::= (identifier)
  multiplicity ::= multiplicity-bound [ '..' multiplicity-bound ]
  multiplicity-bound ::= (number) | '*'
  default-value ::= (string)
  ```
* **Visibility** : Change visibility property.
* **Add** (`Ctrl+Enter`) : Add one more attribute in the below.
* **Delete** (`Ctrl+Delete`) : Delete the attribute
* **Move Up** (`Ctrl+Up`) : Move the attribute up.
* **Move Down** (`Ctrl+Down`) : Move the attribute down.

## Operation

To add an Operation:

1. Select a Classifier.
2. Select **Model | Add | Operation** in Menu Bar or **Add | Operation** in Context Menu.

You can use **QuickEdit** for Operation by double-click or press `Enter` on a selected Operation.

* **Operation Expression** : Edit Operation expression.

  *Syntax of Operation Expression*

  ```
  operation ::= [ '<<' stereotype `>>` ] [ visibility ] name [ '(' parameter-list ')' ] [ ':' return-type ]
  stereotype ::= (identifier)
  visibility ::= '+' | '#' | '-' | '~'
  name ::= (identifier)
  parameter-list ::= parameter [ ',' parameter ]*
  parameter ::= (identifier)
  return-type ::= (identifier)
  ```
* **Visibility** : Change visibility property.
* **Add** (`Ctrl+Enter`) : Add one more operation in the below.
* **Delete** (`Ctrl+Delete`) : Delete the operation
* **Move Up** (`Ctrl+Up`) : Move the operation up.
* **Move Down** (`Ctrl+Down`) : Move the operation down.

To add a Parameter, see [Parameter](#parameter).

To show or hide Operation Signatures, see [Show Operation Signature](https://docs.staruml.io/master/user-guide/formatting-diagram#show-operation-signature).

## Parameter

To add a Parameter:

1. Select an Operation.
2. Select **Model | Add | Parameter** in Menu Bar or **Add | Parameter** in Context Menu.

## Template Parameter

To add a Template Parameter:

1. Select an Element.
2. Select **Model | Add | Template Parameter** in Menu Bar or **Add | Template Parameter** in Context Menu.

You can use **QuickEdit** for Template Parameter by double-click or press `Enter` on a selected Template Parameter.

* **Template Parameter Expression** : Edit Template Parameter expression.

  *Syntax of Template Parameter Expression*

  ```
  template-parameter ::= [ '<<' stereotype `>>` ] [ visibility ] name [':' type ] [ '=' defaut-value ]
  stereotype ::= (identifier)
  visibility ::= '+' | '#' | '-' | '~'
  name ::= (identifier)
  type ::= (identifier)
  default-value ::= (string)
  ```
* **Visibility** : Change visibility property.
* **Add** (`Ctrl+Enter`) : Add one more template parameter in the below.
* **Delete** (`Ctrl+Delete`) : Delete the template parameter.
* **Move Up** (`Ctrl+Up`) : Move the template parameter up.
* **Move Down** (`Ctrl+Down`) : Move the template parameter down.

## Template Parameter Substitution

To add a Template Parameter Substituion:

1. Select a Template Binding element.
2. Select **Model | Add | Template Parameter Substitution** in Menu Bar or **Add | Template Parameter Substitution** in Context Menu.

Each **Template Parameter Substitution** should have `formal` property assigned to a **Template Parameter** of the template element and `actual` property assigned to the actual value for the template parameter.

## Interface

To create an Interface:

1. Select **Interface** in **Toolbox**.
2. Drag on the diagram as the size of Interface.

To create an Interface (model element only) by Menu:

1. Select an Element where a new Interface to be contained.
2. Select **Model | Add | Interface** in Menu Bar or **Add | Interface** in Context Menu.

You can use **QuickEdit** for Interface by double-click or press `Enter` on a selected Interface.

* **Name Expression** : Edit name expression.

  *Syntax of Name Expression*

  ```
  expression ::= [ '<<' stereotype `>>` ] [ visibility ] name
  stereotype ::= (identifier)
  visibility ::= '+' | '#' | '-' | '~'
  name ::= (identifier)
  ```
* **Visibility** : Change visibility property.
* **Add Note** : Add a linked note.
* **Add Constraint** : Add a constraint.
* **Add Attribute** (`Ctrl+Enter`) : Add an attribute.
* **Add Operation** (`Ctrl+Shift+Enter`) : Add an operation.
* **Add Reception** : Add a reception.
* **Add Sub-Interface** : Add a sub-interface.
* **Add Super-Interface** : Add a super interface.
* **Add Realizing Class** : Add an realizing class.

To show an Interface as Lollipop notation, Interface should be realized (See [Interface Realization](#interface-realization)) and then change Stereotype Display to Icon or Icon with Label (See [Stereotype Display](https://docs.staruml.io/master/user-guide/formatting-diagram#stereotype-display)).

To show an Interface as Socket notation, Interface should have dependants (See [Dependency](#dependency)) and then change Stereotype Display to Icon or Icon with Label (See [Stereotype Display](https://docs.staruml.io/master/user-guide/formatting-diagram#stereotype-display)).

To suppress Attributes, see [Suppress Attributes](https://docs.staruml.io/master/user-guide/formatting-diagram#suppress-attributes).

To suppress Operations, see [Suppress Operations](https://docs.staruml.io/master/user-guide/formatting-diagram#suppress-operations).

To suppress Receptions, see [Suppress Receptions](https://docs.staruml.io/master/user-guide/formatting-diagram#suppress-receptions).

To show or hide Operation Signatures, see [Show Operation Signature](https://docs.staruml.io/master/user-guide/formatting-diagram#show-operation-signature).

## Signal

To create a Signal:

1. Select **Signal** in **Toolbox**.
2. Drag on the diagram as the size of Signal.

To create a Signal (model element only) by Menu:

1. Select an Element where a new Signal to be contained.
2. Select **Model | Add | Signal** in Menu Bar or **Add | Signal** in Context Menu.

You can use **QuickEdit** for Classifier (See [Classifier](#classifier)).

## DataType

To create a DataType:

1. Select **DataType** in **Toolbox**.
2. Drag on the diagram as the size of DataType.

To create a DataType (model element only) by Menu:

1. Select an Element where a new DataType to be contained.
2. Select **Model | Add | DataType** in Menu Bar or **Add | DataType** in Context Menu.

You can use **QuickEdit** for Classifier (See [Classifier](#classifier)).

## PrimitiveType

To create a PrimitiveType:

1. Select **PrimitiveType** in **Toolbox**.
2. Drag on the diagram as the size of PrimitiveType.

To create a PrimitiveType (model element only) by Menu:

1. Select an Element where a new PrimitiveType to be contained.
2. Select **Model | Add | PrimitiveType** in Menu Bar or **Add | PrimitiveType** in Context Menu.

You can use **QuickEdit** for Classifier (See [Classifier](#classifier)).

## Enumeration

To create an Enumeration:

1. Select **Enumeration** in **Toolbox**.
2. Drag on the diagram as the size of Enumeration.

To create an Enumeration (model element only) by Menu:

1. Select an Element where a new Enumeration to be contained.
2. Select **Model | Add | Enumeration** in Menu Bar or **Add | Enumeration** in Context Menu.

You can use **QuickEdit** for Enumeration by double-click or press `Enter` on a selected Enumeration.

* **Name Expression** : Edit name expression.

  *Syntax of Name Expression*

  ```
  expression ::= [ '<<' stereotype `>>` ] [ visibility ] name
  stereotype ::= (identifier)
  visibility ::= '+' | '#' | '-' | '~'
  name ::= (identifier)
  ```
* **Visibility** : Change visibility property.
* **Add Note** : Add a linked note.
* **Add Constraint** : Add a constraint.
* **Add Literal** (`Ctrl+Enter`) : Add an enumeration literal.
* **Add Operation** (`Ctrl+Shift+Enter`) : Add an operation.

To suppress Literals, see see [Suppress Literals](https://docs.staruml.io/master/user-guide/formatting-diagram#suppress-literals).

## Enumeration Literal

To add an Enumeration Literal:

1. Select a Classifier.
2. Select **Model | Add | Enumeration Literal** in Menu Bar or **Add | Enumeration Literal** in Context Menu.

You can use **QuickEdit** for Enumeration Literal by double-click or press `Enter` on a selected Enumeration Literal.

* **Name Expression** : Edit name expression.

  *Syntax of Name Expression*

  ```
  expression ::= [ '<<' stereotype `>>` ] [ visibility ] name
  stereotype ::= (identifier)
  visibility ::= '+' | '#' | '-' | '~'
  name ::= (identifier)
  ```
* **Visibility** : Change visibility property.
* **Add** (`Ctrl+Enter`) : Add one more literal in the below.
* **Delete** (`Ctrl+Delete`) : Delete the literal
* **Move Up** (`Ctrl+Up`) : Move the literal up.
* **Move Down** (`Ctrl+Down`) : Move the literal down.

## Relationship

Relationship is an abstract element representing a relationship between UML elements.

Subclasses of Relationship are:

* [Generalization](#generalization)
* [Association](#association)
* [Aggregation](#aggregation)
* [Composition](#composition)
* [Dependency](#dependency)
* [Interface Realization](#interface-realization)
* [Component Realization](https://docs.staruml.io/master/component-diagram#component-realization)
* [Include](https://docs.staruml.io/master/use-case-diagram#include)
* [Exclude](https://docs.staruml.io/master/use-case-diagram#exclude)

You can use **QuickEdit** by double-click or press `Enter` on a selected relationship.

* **Name Expression** : Edit name expression.

  *Syntax of Name Expression*

  ```
  expression ::= [ '<<' stereotype `>>` ] [ visibility ] name
  stereotype ::= (identifier)
  visibility ::= '+' | '#' | '-' | '~'
  name ::= (identifier)
  ```
* **Visibility** : Change visibility property.
* **Add Note** : Add a linked note.
* **Add Constraint** : Add a constraint.

## Generalization

To create a Generalization:

1. Select **Generalization** in **Toolbox**.
2. Drag from an element (to be special) and drop on another element (to be general).

You can use **QuickEdit** for Relationship (See [Relationship](#relationship)).

## Association

To create an Association (or Directed Association):

1. Select **Association** (or **Directed Association**) in **Toolbox**.
2. Drag from an element and drop on another element.

You can use **QuickEdit** for Relationship (See [Relationship](#relationship)).

You can also use **QuickEdit** for Association End by double-click at the end side of an Association.

* **Name Expression** : Edit name expression.

  *Syntax of Name Expression*

  ```
  expression ::= [ '<<' stereotype `>>` ] [ visibility ] name
  stereotype ::= (identifier)
  visibility ::= '+' | '#' | '-' | '~'
  name ::= (identifier)
  ```
* **Visibility** : Change visibility property.
* **Navigability** : Change navigability property.
* **Aggregation Kind** : Change aggregationKind property.
* **Multiplicity** : Change multiplicity property.
* **Add Qualifier** : Add a qualifier (attribute) to the AssociationEnd.

## Aggregation

To create an Aggregation:

1. Select **Aggregation** in **Toolbox**.
2. Drag from an element (to be a part) and drop on another element (to be whole).

You can use **QuickEdit** for Relationship (See [Relationship](#relationship)).

You can also use **QuickEdit** for AssociationEnd by double-click at the end side of an Association (See [Association](#association)).

> **Note**
>
> Aggregation is an association whose `aggregation` propery is `shared`.

## Composition

To create a Composition:

1. Select **Composition** in **Toolbox**.
2. Drag from an element (to be a part) and drop on another element (to be whole).

You can use **QuickEdit** for Relationship (See [Relationship](#relationship)).

You can also use **QuickEdit** for AssociationEnd by double-click at the end side of an Association (See [Association](#association)).

> **Note**
>
> Composition is an association whose `aggregation` propery is `composite`.

## Dependency

To create an Dependency:

1. Select **Dependency** in **Toolbox**.
2. Drag from an element (client) and drop on another element (supplier).

You can use **QuickEdit** for Relationship (See [Relationship](#relationship)).

## Interface Realization

To create an Interface Realization:

1. Select **Interface Realization** in **Toolbox**.
2. Drag from an element (realizing) and drop on an interface (to be realized).

You can use **QuickEdit** for Relationship (See [Relationship](#relationship)).

## Association Class

To create an Association Class by linking two Classifiers:

1. Select **Association Class** in **Toolbox**.
2. Drag from an element and drop on another element.
3. An Association and a Class connected to the association will be created.

To create an Association Class by linking Association and Class:

1. Select **Association Class** in **Toolbox**.
2. Drag from an Association (or Class) and drop on a Class (or Association).
3. The Class will be connected to the Association.

## Template Binding

To create a Template Binding:

1. Select **Template Binding** in **Toolbox**.
2. Drag from a bound element and drop on a template element.
3. If required, create [Template Parameter Substitution](#template-parameter-substitution).

You can use **QuickEdit** for Template Binding by double-click or press `Enter`.

* **Visibility** : Change visibility property.
* **Add Note** : Add a linked note.
* **Add Constraint** : Add a constraint.
* **Add Template Parameter** : Add a template parameter substitution.

## Frame

To create a Frame view of a particular model element:

1. Select **Frame** in **Toolbox**.
2. Drag on the diagram as the size of Frame.
3. Select a model element which the Frame represents in **Element Picker Dialog**

## Tag

To add a Tag of an element:

1. Select an element to add a Tag.
2. Select **Model | Add | Tag** in Menu Bar or **Add | Tag** in Context Menu.

You can select one of tag kinds: **string**, **reference**, **boolean**, or **number**. The `value` property corresponds to **string** kind. The `reference` property corresponds to **reference** kind. The `checked` property corresponds to **boolean** kind. The `number` property corresponds to **number** kind.

The Tags can be shown in views by checking **Format** > **Show Property** menu item. If you don't want to be shown, check `hidden` property.

You can manage Tags conveniently in [Tag Editor](https://docs.staruml.io/master/user-guide/user-interface#tag-editor) with relationships of Stereotype's Attributes.

## Constraint

To add a Constraint of an element:

1. Select an element to add a Constraint.
2. Select **Model | Add | Constraint** in Menu Bar or **Add | Constraint** in Context Menu.

You can create a Constraint view on a diagram by drag and drop from Model Explorer.