MidTerm Exam Preparation

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Mid-Term Exam Preparation
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Sources of Info

• Relevant Gittleman text chapters
• Powerpoint Slides
• Java Example Programs
• Java Mutual Support List
• Your Assignments and Projects

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Basic Object Concepts

• What is an object
• Objects contain both behavior and data
• Benefits of the use of the object model

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Classes and objects

• A class as a "template"
• An object as an instance of a class (represents
  one "real" object)

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Object Oriented Programming Definitions

• Object
• Encapsulation
• Inheritance
• Polymorphism
• Clients and servers
• Class hierarchy
• class, subclass and superclass
• class Object at top of hierarchy

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Planning Your Logic

• Pseudocode
• No rigid rules
• Sometimes called structured English
• Flowcharts
• More visual
• Use of special symbols (rectangle, diamond, oval,
  parallelogram)
• Flowcharts of selection
• Flowcharts of iteration
• test-before loops
• test-after loops

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Java Language Fundamentals

• Literals, variables, classes
• Conventions on naming variables and classes
• Structure of a Java expression
• receiving object, method, argument(s)
• Assignment statements

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Data Types and Objects

• What are basic data types?
• What are examples of objects?
• How do you work with data types? (i.e., you
  manipulate them in other ways, but you do not
  send them messages)
• How do you work with objects? (i.e., you send
  them messages)

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Java Fundamentals

• Source code, object or bytecode
• Pre-written classes and use of the Java API
• Creating new projects
• Packages
• Building/compiling and running
• import statement

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Java Naming Conventions

• Class names
• Variable names
• Method names

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Java statements

• Assignment statements and the assignment operator
• Structure of an assignment statement
• Precedence
• Short cut notations ( and , etc.)
• Punctuation in java statements
• Simple statements and compound statements (i.E.,
  Blocks)
• Some java statements are assignment statements
  and some are not. For example
• totalTax oldTax newTax
• myCar.setWeight(3000)

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Control Structures

• Sequence
• Selection
• Iteration
• Implementation of these in java

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Classes

• The App class
• Has a main method
• Constructs instances of worker or support
  class(es)
• Does most of the input and output
• Drives the worker/support class through a set of
  steps
• Support or worker classes
• Maintains info in instance variables
• Contains methods which describe most of the
  application logic
• Methods return values to the main method, or
  change instance variables, or are used by other
  methods of the worker class

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Writing classes

• Structure of a class
• Heading line
• How you designate instance variables
• Instance variables should normally be private
• How where you designate constants
• Where the methods are written in the class

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Writing Methods

• Header line
• Access modifier
• Return value
• Method name
• Arguments
• Declaring their type
• Naming them
• Writing the logic
• Remembering that local variables are discarded
  when the method ends
• Remembering to return what is expected
• Method does one task
• Method name descriptive of that task
• Method returns zero or one value
• Can not return more than one

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Using Instance Methods

• Requesting an object to carry out some behavior
  (i.e., execute a method) is how the work of a
  Java program is completed
• Structure objectName.methodName(arguments)
• Example taxTotal carRental.calcTax(totSale)
• Example myPerson.setDateOfBirth(11/07/1984)
• When you write a Java statement, when do you make
  it an assignment statement and when not ???

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Class Methods

• Asking the class itself to carry out some
  behavior
• Example
• ageStr JOptionPane.showInputDialog(Enter Age
  )

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Constructors

• Writing a constructor method for a worker or
  support class
• The no arg constructor
• The fully-populating constructor
• Java gives you automatically a no arg
  constructor for a class if you dont write any
  constructors of your own
• Using a constructor (for example in the main
  method) to construct an object
• Example Person myPerson new Person()
• Example Person myPerson new Person(Louise,
  5.3)
• Example Date today new Date()

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Getters and Setters

• Getters to retrieve data from the instance
  variables of an object
• Example String carColor myCar.getColor()
• Setters to store data into the instance variables
  of an object
• Example myCar.setColor(red)
• Naming conventions for getters and setters
• Use of a fully-populating constructor as an
  alternative to using setters to give values to
  instance variables

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Conditional Statements

• Boolean expressions
• Structure of an "if" statement
• How an "if" statement works
• Precedence

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Boolean expressions

• Always evaluate to a boolean value True or False
• Relational operators (, lt, gt, !, etc.)
• REMBEMBER only works on data types
• Messages/methods that return a boolean
  (custname.Startswith("sa"))
• Compound expressions involving more than one
  boolean value
• !

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Formatting Conditional Statements

• if (boolean-expression-1)
• statement-1
• if (a b)
• statement-1

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Formatting Conditional Statements

• if (tapeType.startsWith("Fi"))
• statement-1
• else
• statement-2

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Nested if Statements

• How they are formatted
• Understanding how they are executed (i.e., under
  what conditions do you get to point xx, and after
  that is executed what happens next)

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Formatting "else if" Statements

• if (tapeType.equalsIgnoreCase("Classic"))
• statement-1
• else if (tapeType.equalsIgnoreCase("First Run")
• statement-2
• else if (tapeType.equalsIgnoreCase("Adult")
• statement-3
• else
• statement-4

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Iteration

• Logic
• Test before and test after loops
• for, while and do while loops
• Use of blocks

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for, while and do while loops

• Structure of each
• Formatting of each
• When you choose each
• Using each to solve a problem

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Specific Classes

• Know the methods we have used for the following
  classes
• String class
• JOptionPane class
• Date class