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 – 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