In a class diagram, what symbol is used for the protected access modifier?

A class is shown as a solid-outline rectangle containing the class name, and optionally with compartments separated by horizontal lines containing features or other members of the classifier.

Class SearchService - analysis level details

When class is shown with three compartments, the middle compartment holds a list of attributes and the bottom compartment holds a list of operations. Attributes and operations should be left justified in plain face, with the first letter of the names in lower case.

Class SearchService - implementation level details. The createEngine is static operation.

Middle compartment holds attributes and the bottom one holds operations.

Class SearchService - attributes and operations grouped by visibility.

Attributes or operations may be grouped by visibility. A visibility keyword or symbol in this case can be given once for multiple features with the same visibility.

Math is utility class - having static attributes and operations (underlined)

Utility is class that has only class scoped . As such, utility class usually has no instances.

Class SearchRequest is abstract class.

Abstract class was defined in UML 1.4.2 as class that can't be directly instantiated. No object may be a direct instance of an abstract class.

UML 2.4 mentions abstract class but provides no definition. We may assume that in UML 2.x abstract class does not have complete declaration and "typically" can not be instantiated.

The name of an abstract class is shown in italics.

Nested Classifiers

Class LinkedList is nesting the Element interface. The Element is in scope of the LinkedList namespace.

A class or interface could be used as a namespace for various classifiers including other classes, interfaces, use cases, etc. This nesting of classifier limits the visibility of the classifier defined in the class to the scope of the namespace of the containing class or interface.

In obsolete UML 1.4.2 a declaring class and a class in its namespace may be shown connected by a line, with an "anchor" icon on the end connected to a declaring class (namespace). An anchor icon is a cross inside a circle.

UML 2.x specifications provide no explicit notation for the nesting by classes. Note, that UML's 1.4 "anchor" notation is still used in one example in UML 2.4.x for as an "alternative membership notation".

Template class Array and bound class Customers. The Customers class is an Array of 24 objects of Customer class.

UML classes could be templated or .

The example to the left shows bound class Customers with substitution of the unconstrained parameter class T with class Customer and boundary parameter n with the integer value 24.

Interface

Interface SiteSearch.

An interface is a classifier that declares of a set of coherent public features and obligations. An interface specifies a contract.

In UML 1.4 interface was formally equivalent to an with no attributes and no methods and only .

An interface may be shown using a rectangle symbol with the keyword «interface» preceding the name.

Interface Pageable

The obligations that may be associated with an interface are in the form of various kinds of constraints (such as pre- and postconditions) or protocol specifications, which may impose ordering restrictions on interactions through the interface.

Interface SiteSearch is realized (implemented) by SearchService.

Interface participating in the interface realization dependency is shown as a circle or ball, labeled with the name of the interface and attached by a solid line to the classifier that realizes this interface.

Interface SiteSearch is used (required) by SearchController.

The usage dependency from a classifier to an interface is shown by representing the interface by a half-circle or socket, labeled with the name of the interface, attached by a solid line to the classifier that requires this interface.

Visibility allows to constrain the usage of a named element, either in namespaces or in access to the element. It is used with classes, , generalizations, element import, package import.

UML has the following types of visibility:

• public
• package
• protected
• private

Note, that if a named element is not owned by any namespace, then it does not have a visibility.

A public element is visible to all elements that can access the contents of the namespace that owns it. Public visibility is represented by '+' literal.

A package element is owned by a namespace that is not a package, and is visible to elements that are in the same package as its owning namespace. Only named elements that are not owned by packages can be marked as having package visibility. Any element marked as having package visibility is visible to all elements within the nearest enclosing package (given that other owning elements have proper visibility). Outside the nearest enclosing package, an element marked as having package visibility is not visible. Package visibility is represented by '~' literal.

A protected element is visible to elements that have a generalization relationship to the namespace that owns it. Protected visibility is represented by '#' literal.

A private element is only visible inside the namespace that owns it. Private visibility is represented by '-' literal.

Operation executeQuery is public, isPoolable - protected,
getQueryTimeout - with package visibility, and clearWarnings is private.

If some named element appears to have multiple visibilities, for example, by being imported multiple times, public visibility overrides private visibility. If an element is imported twice into the same namespace, once using a public import and another time using a private import, resulting visibility is public.

What symbol is used for protected access modifiers?

What does a +/

What are the symbols used in class diagram?

Which of the following symbols indicates protected visibility for an attribute or method in a class diagram?