Rapid Review Chapter 1 - 5 Steps To A 5

Front 1

Class

Back 1

A programming unit that captures abstraction. We talk about the state or attributes (nouns that describe) of an object (the abstraction) and its behavior, the services or tasks it can perform (think of verbs), encapsulated in its methods.

Front 2

Class Heading

Back 2

The line of code that names the class and defines its relationship, if any, or another class or to interfaces.

Front 3

Instance

Back 3

An object of a specified class type. More than one object may be instantiated (created) at any given time.

Front 4

Instance Variable

Back 4

A variable that must be referenced through an instance of the class. These variables define the attributes of a particular instance and are private.

Front 5

Field

Back 5

Another name for instance variable.

Front 6

Constant

Back 6

A value that cannot be changed during program execution. The purpose of constants is to make programs more readable and to make it easier for the programmer to change a value that is used repeatedly through out the program for example, a tax rate, specified with the keyword final.

Front 7

Class Variable

Back 7

A variable that is shared by all instances of a class. The keyword static is used to define a class variable. It may be referenced using the class name, but, more importantly, if changed by one instance of the class, its value is changed for all instances.

Front 8

Method

Back 8

A task that an instance of a class can perform.

Front 9

Method Signature

Back 9

The method heading. This defines the method as public, private, or protected; specifies its return type; lists the method name; and specifies its parameters. The name is not important to the definition of signature but, if the method is well named, it well you what the method does.

Front 10

Method Overloading

Back 10

The idea that two methods may have the same name as long as they have different signatures. (A consequence of this is that the system can distinguish which method is to be used based upon the parameter sequence.)

Front 11

Visibility Modifier

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Defines how a construct can be accessed; for our purpose, usually applied to a variable or a method.

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Public

Back 12

Visible to all users of the class.

Front 13

Private

Back 13

Invisible to users of the class; visible only within the class itself.

Front 14

Protected

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(not covered on the AP exam, except in the context of the case study): Visible only to the class and subclass of the class.

Front 15

Constructor Method

Back 15

A method whose task is to instantiate (create or build) an object, accomplished by initialing the instance variable. You can pick out a constructor easily because its name must be the same name as the class name and there is no return type. There may be more that one constructor (this is called overloading), distinguished by a difference in number or types of arguments in the parameter list.

Front 16

Default

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A value that will be used instead of a programmer-specified parameter, often for a constructor. A constructor that uses no parameters at all, instead substituting predefined values, is often called a default constructor.

Front 17

Accessor Method

Back 17

A method that returns the value stored in an instance variable. This is the way a client program or another class gains access to information about the state of an object.

Front 18

Modifier or Mutator Method

Back 18

A method that changes the state of an object. These methods are usually, but not always, void, meaning they do not return a value.

Front 19

Helper Method

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Private method used within a class. A helper method may avoid repetition of code or may aid in breaking down a complicated method into simpler tasks.

Front 20

Parameter

Back 20

Required information passed to a method so that it may accomplish its task.

Front 21

Formal Parameters

Back 21

The parameters listed in a method signature. For example, in the method signature:
public int sumUp(int first, int last)
the formal parameters are first and last.

Hint 21

None

Front 22

Actual Parameters

Back 22

The values supplied by the client in the parameter list of a method call. In the method call:
int sum = nums.sumUp(start, end)
the actual parameters are stare and end.

Hint 22

None

Front 23

Explicit Parameters

Back 23

Information passed in the parameter list:
int sum = nums.sumUp(start, end)
the explicit parameters are start and end.

Hint 23

None

Front 24

Implicit Parameters

Back 24

The object upon which a method id called:
int sum = nums.sumUp(start, end)
the implicit parameter is nums.

Hint 24

None

Front 25

Local Variable

Back 25

Variable declared within a method.

Front 26

Client

Back 26

User of a class; may be the main method or the method of another class

Front 27

Main method

Back 27

The method in an application where execution begins.

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Implementation

Back 28

Code that defines a construct.

Front 29

This

Back 29

A reserved word for the implicit parameter; used within a class when a referenced to the implicit parameter is needed.