Computer Science Terms

Computer Science Terms:

Composite structure: the size of a typical software system implies that it must be broken down into manageable pieces of this

Composition: the process of building a system using simpler parts or components

Abstraction: the process of ignoring details irrelevant to the problem at hand and emphasizing essential ones. To abstract is to disregard certain differentiating details

Data: the info the program deals with

Functionality: what the program does with the data, the responsibility of the object to do

Object: the most abstract description of a basic component of an object oriented system

Values: a fundamental piece of info that can be manipulated by the program

Types: a set of related values along with the operations that can be preformed with them

Object: fundamental abstractions from which systems are built

Classes: a set of objects having the same features and properties

State of an object: the set of data maintained by an object at any given time

Reference values: a value that denotes an object

Data descriptions: properties of the object (name, date, etc)

Associated value: a property an object has at any given time

Variable: a portion of memory reserved to hold a single value

Instance variables: a variable that is a permanent part of an object: memory space for the variable is allocated when the object is created

Immutable: an object that's state cannot be changed

Mutable: and object that's state can be changed

*An object is characterized by the features it offers*

1. Query: a request for data

2. Command: a request to change state

Float & Double: sets of real rational numbers (i.e. 170000 or 1.4e12)

Char: set of values representing Unicode characters

Boolean: true or false values

Int value: contains a single integer

String: and immutable object that contains a sequence of characters

Identifier: a sequence of characters that can be used as a name in a Java program

Literal: a sequence of characters that denotes a particular value in a Java program

Comments: explanatory remarks that are included in a program for the benefit of a human reader and are ignored by the compiler

Chapter 2:

Features of an object: queries and commands

*A client queries and commands a server*

Specification (interface): definition of an object's features, as seen by its clients

Implementation: provides the internals that actually make up the features

Packages: groups of classes

Public class: indicates that the objects of that class will be accessible throughout the system

Public void: a command is a query that changes the state of the object but do not provide the client with a value

Method: a language construct that defines and implements a query or command

Constructor: a language construct used to create and initialize an object

Static diagrams: diagrams showing classes

Stub: dummy method or constructor

New: used to invoke a constructor and create an object

Interaction diagram: means of illustrating the order in which objects interact

Statement: provides the action that the processor is to carry out

Expression: a language construct that describes how to compute a particular value. Evaluation of this produces a value

Reset: invoked command to change the count to zero

incrementCount: to increment the count by 1

Assignment: (variableName = expression Wink - a statement that instructs the processor to computer a value and store it in a variable

Parameters: elements of information that must be provided

Method variable: a variable that is created when a method is invoked and de-allocated when the processor finished executing the method

Numeric promotion: the conversion of and int to a double

Operator precedence: * / % + -

Left associative: two expressions with equal precedence are evaluated from L to R

Compilation unit: a file containing the definition of one or more classes of a package

Import statement: placed at the beginning of a compilation unit (file), after a package statement, and apply to all classes defined in the compilation unit

Assignment expression: consists of a variable (left hand side), assignment operator (=) and expression (right hand side)

Increment expressions: il++ ++il

Decrement expressions: il- - - -il

Bitwise operators: allow the bit patterns of integral values to be manipulated

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