LF5 klausur

Unified Modelling Language

• its a box

• with a section for the name

• one for the attributes (with heading ‘attributes’)

• one for the methods (with heading ‘methods’)

+, - and # are used to indicate the visibility of a member in uml

• + is public

• - is private

• # is protected

• method name should be in italic

• if one method is abstract , the class is abstract

• name {abstract} alternative annotation

Object-oriented programming (OOP) models real-world elements using objects that interact by exchanging messages (calling methods).

A blueprint for creating objects. It defines the behavior (methods) and properties (attributes) of the objects.

Variables within a class that store the properties of an object.

Restricts access to instance variables from outside the class, encapsulating the object's data.

A special method that creates objects, allocates memory, and initializes the object's variables.

Same name as the class and no return type.

Java provides a default constructor if none is defined, which initializes instance variables with default values.

Constructors that accept arguments to initialize instance variables with specific values when the object is created.

Inside a constructor, this refers to the current object and is used to access or modify its attributes.

Creating new classes (derived/subclasses) from existing ones (base/superclasses). This establishes an "is-a" relationship.

1. Code reuse: Subclasses inherit attributes and methods from superclasses, avoiding code duplication.

2. Maintainability: Changes to shared code only need to be made in the superclass.

3. Extensibility: New functionality can be added by creating new subclasses.

Subclasses are more specific versions of their superclass.

The process of extracting common features from multiple classes into a superclass to reduce redundancy.

Used to establish an inheritance relationship between a subclass and a superclass.

A reference to the superclass, used to call superclass constructors or access superclass members.

Allows subclasses to directly access attributes of the superclass, while still restricting access from other external classes.

Abstract classes cannot be instantiated. They serve as templates for subclasses, defining common behavior and attributes that subclasses must implement.

Declared in abstract classes without implementation. Subclasses are required to provide the implementation.

abstract

An association represents a "has-a" relationship between objects of different classes.

Defines the number of objects involved in the relationship (e.g., one-to-one, one-to-many).

Indicates which class(es) "know" about the other class.

Associations are implemented using instance variables that hold references to other objects.

A strong form of association, a "whole-part" relationship where the part is dependent on the whole.

1. Attributes that belong to the class itself, not to specific instances.

2. There is only one copy of a static variable, shared by all objects of the class.

3. Used to store values that are common to all instances of a class.

4. Declared using the static keyword.

1. Methods that belong to the class and can be called without creating an instance of the class.

2. They can only access static variables.

3. Declared using the static keyword.

Encapsulating game logic in a separate class improves modularity, maintainability, and flexibility.

The state of a game object.