Java Object-Oriented Programming: AP Computer Science B

Discuss classes and objects for data record with states and behaviors. States are properties or variables. Behaviors are methods. Any simple example of SimpleCircle class is used to show the idea of class and objects.

Exercise on different object-oriented program styles. 

[Java Coffee Break] Showing the concept of using objects as data collection. 

A data object can with proper information hiding and encapsulation should only be accessed by getter methods and setter methods. 

Discussion on the constructor methods for creating objects.

Construct a car fuel usage information class and object to exercise on basic object oriented programming skills. 

Continue the Fuel Series program to add two member (instance methods) into it. 

Discuss the scope and lifetime of local variables, instance variables (methods), and class variables (methods).

Modify the Fuel2 project into Fuel3 project with multiple objects. 

Discuss the visibility modifiers (public, protected, default (no modifier) and private ) and where a variable, a method or object can be accessed.

Modify Fuel3 project into array format. 

Starts Design Styles for Classes and Objects. First lecture on Static Members.

Modify Fuel4 into arraylist format.

Use an example to show the idea of Data Encapsulation in Java

Discuss how to design an immutable class. Three principles:

(1) All data fields must be private.

(2) No public setter methods.

(3) No accessor methods should return reference data type so that the reference data type may provide a back door (some mutator metthod) to update internal data which is supposed to be immutable.

Demonstrate the idea of static variables and the instance variables. 

Introduce this keyword, it is a keyword to indicate the current object to distinguish the instance variable from argument, local variable and other variables of the same name. Class.variable is also presented.

Chapter project using AP Physics Rules for calculation of projectile. 

Show the internet resources available for eC Learning Channel by Dr. Eric Chou to support this course. 

My Udemy: https://www.udemy.com/user/eric-chou/

Youtube channel: https://www.youtube.com/c/EricChouPHD

Facebook: https://www.facebook.com/profile.php?id=100007999848206

Quora: https://www.quora.com/profile/Eric-Chou-21 

Twitter: https://twitter.com/eCwarlephant

Email: echou510@gmail.com

Review of classes and objects and provide overview for the Object-Oriented Programming in Unit 4 and Chapter 10.

Use Course class as an example to show how to define a class and class coherence.

Thinking in Object-Oriented Programming way. To build a complete class for BMI calculation.

Design a BMR class to experience designing a cohesive and complete class.

Create two classes for the Geometric project 1. Rectangle and Triangle classes. 

Using conversion from a structual program into the BMR class and TestBMR class as an example to demonstrate the conversion between a structural program to object-oriented program.

To design classes, you need to explore among classes. The common relationships among classes are association, composition and inheritance.

Video clip to shop the relationship of classes including is_a and has_a relationships. 

Use the violet tool to construct class diagram with Aggregation relationship.  Build a Lego class has has_A relationship for the Lego class and Rectangle and Triangle classes. 

Lab project on stack of integers. This is the first project in a series on user-defined data structure using object-oriented programming. These basic data structure will be very useful in AP Exam. It is also a good introduction for Unit 5 (Algorithms and Data Structure).

This lab project is also a good example for OOP design guidelines for coherence, completeness and design styles.

Provide examples, demo programs, and lab project to use this.

Use of this reference for conversion of static method and constructor calls.

Use String, StringBuilder and StringBuffer classes to separate the responsibilities for operating strings. (Part 1)

Use String, StringBuilder and StringBuffer classes to separate the responsibilities for operating strings. (Part 2)

Use Palindrome check to demonstrate the advanced String processing and StringBuilder/StringBuffer Class.

Use load Class to demonstrate the class abstraction and Ecapsulation

Show the three important top level classes for Java language: Object, Number and String classes.

Add the methods inherited from the Object class into the Rectangle and Triangle Class. Also add the mutator methods into these classes. 

Introduction of BigInteger and BigDecimal classes along with conversion of int, double, Integer, Double, String data type conversion. BigInteger and BigDecimal classes are data classes with mathematical operations.

In this lab project, the concept of using Raw ArrayList of Object type is tested.  Also, student are required to handle the removal of elements from an arraylist. (from the end of an arraylist instead of from the head.)

Answer Key to the Lab

Inheritance enables you to define a general class (i.e., a superclass) and later extend it to more specialized classes (i.e. subclass)

The keyword super refers to the superclass and can be used to invoke the super-class's methods and constructors.

Polymorphism means that a variable of a supetype can refer to a subtype object.

To override a method, the method must be defined in the subclass using the same signature and the same return type as in its superclass. Overloading means ti define multiple methods with the same name but different signatures.

Show the concept of Inheritance, member properties, overriding, overloading. 

Apply the Inheritance and overriding methods to Geometric project. 

Use numbers package to demonstrate polymorphism.

One object reference can be typecast into another object reference. This is called casting object. Define method return value and parameters in more general (or abstract) superclass will make it more useful.

Example for Object class in equality package.

A method can be implemented in several classes along the inheritance chain. The JVM decides which method is invoked at run-time. (super.getNum(), this.getNum())

Exercise Polymorphism on the Geometric Project.  Add three more classes, Square, Cube and Equilateral. 

Show the nature and need for polymorphism and why it makes Java language platform-dependent with dynamic binding (linking)

Constructors for Parent class and Child class for the initialization of data fields in parent objects and children objects.

A protected member of a class can be accessed from a subclass.

Exceptions are thrown from a method. The caller of the method can catch and handle the exception.

Exceptions are objects, and objects are defined using classes. The root class for exceptions is java.lang.Throwable.

A handler for an exception is found by propagating the exception backward through a chain of method calls, starting from the current method.

A group of advanced topics on exception handling.

You can define a custom exception class by extending the java.lang.Exception class. We provide an example to show how to do it.

Discuss the keyword assert that can be used to check the program correctness. If the assertion is false, an error will be raised. This operator make initial error for program checking and testing. It is replaced by JUnit Test which is in another course that we have "Java JUnit for Unit Testing

Objected Oriented Programming is for the following purpose: (1) Multi-threading, (2) Dynamic Binding, (3) Module Management. 

Reading Geometric Object information from file. Add the Exception Handling mechanism into the program. 

The file class contains the methods for obtaining the properties of a file/directory and for renaming and deleting a file/directory.

This lecture focused on the general I/O concepts and the Stream class which is the top level class for the data stream hierarchy. 

DataInputStream and DataOutputStream for the int, double, and other primitive data type and String data type I/O is presented. 

Using BufferedInputStream, BufferedOutputStream,BufferedWriter, BufferedReader to speed up the I/O for Java Programs. 

Write objects to files with ObjectOutputStream and read in objects from ObjectInputStream. 

After learning the object-oriented programming, students need to understand what is the purpose for object-oriented programming. OOP is widely used for class management and library building.  In modern terms, the packages of library code are called module, package, application programming interface (API), or even bigger, design framework. All of these are built up using object-oriented programming technology.  The Java Core classes means the classes available in Java development kit (JDK) that came with the Java compiler. 

Read and write objects from files or to files.  This is one of the project in the Geometric project series to work on the file operation (using Object Streams). Class used as a format of data record in this lab project. 

Advanced Topics in advanced object stream

Just like you can read data from a file on your computer, you ca read data from a file on the Web.

An abstract class cannot be used to create objects. An abstract class can contain abstract methods, which are implemented in concrete subclasses.

Number is an abstract superclass for numeric wrapper classes, BigInteger, and BigDecimal.

Use abstract class to organize classes sharing the same methods and data fields together. 

GregorianCalendar is a concrete subclass of the abstract class Calendar.

Discuss the final keyword and the abstract methods.

Using an event listener for a button to explain the anonymous class. Anonymous class is very useful in GUI design.

Present the nature of Abstract Class

Add two anonymous class (actually should be anonymous objects) into the arraylist glist. 

An interface is a class-like construct that contains only constants and abstract methods.

The Comparable interface defines the compareTo method for comparing objects.

The Cloneable Interface specifies that an object can be cloned.

The Iterable Interface has one method iterator(). The Iterator Class has hasNext(), next() and remove() methods.

The ListIterator Class many more methods.

These three interfaces are useful to allow the classes that implements these interfaces to have the iterator to traverse through the class with these three interfaces.

Show how interfaces can be used. 

Compare and contrast between abstract class and interface. Both of them are useful to provide a class with extra feature. Abstract class can be viewed as core data class, while interface can be viewed as a collection of unimplemented methods. An abstract class implemented an interface is a core data class with the collection of unimplemented methods.

Use Rational Class to demonstrate a class extend Number abstract class and implement Comparable Interface.

Rewrite the Geometric10 to Geometric11 using iterator interface to access the elements. 

A class can implement multiple interfaces, but it can only extend one superclass.

Overview of Java Design Patterns

Adapter class to curb the difficulty to use an abstract class or interfaces. The reason may be in-compatibility among interfaces or un-wanted methods.

Adapter pattern to allow an adapter to drive polymorphic methods among incompatible interfaces or abstract classes.

Use the simplest Model-View-Controller (MVC) design pattern, front controller design pattern, to demonstrate idea of behavioral design pattern.

Front controller design pattern can also be named as "single dispatcher design pattern" is one of the simple but powerfule design pattern. It is a good example to understand design patterns.

Use Adapter Design Pattern as an Example to show the combination of Interface, Abstract Class and Class can work together as Adapter Design Pattern 

Introduce Java GUI Programming Toolkits (AWT/Swing/SWT/Javafx) as Examples for Inheritance and Object-Oriented Programming in General

Introduce the user-defined GUI Application Classes in Swing and Javafx

Go over the topics in GUI Programming (Containers, Components, Listeners, Interface, Data Model) and finish with one Sparring Score example before going into serious GUI topics.

Overview of the AWT/Swing package class hierarchy. 

Discuss the basic GUI program structure with the brief explanation on Frame, JFrame, Applet, JApplet and their Anatomy. 

One simple example for 2nd Level containers (also component) JPanel. 

Basic Helper class that represents many objects in the GUI environment including Color, Font, FontMetrics, Graphics, and Dimension

Discuss the general issues about graphics design in AWT/Swing

Use awt.Applet and Rectangle3 class to as a basic Java graphic development platform. 

Discussion of drawing basic geometric objects. 

Use awt.Applet and Rectangle3 class to as a basic Java graphic development platform. 

Use javax.swing.JApplet (BlueJ default style) and Rectangle3 class to as a basic Java graphic development platform. 

Use javax.swing.JApplet in a JFrame and Rectangle3 class to as a basic Java graphic development platform. 

Introduce the event-driven programming environment in java.awt API. 

Event source, event object, event listener, event handler and event target. 

Event Listener, event handler method and anonymous inner class for simplification of event listener and handler design. 

Design Flow of GUI Projects

Introducing the recursion pattern in real-life and computer arts.  Using a recursive rectangle drawing program to show how to create visual recursion. 

Further discuss the fractals using the Sierpinski Triangle as an example. 

Using factorial algorithm to explain tail recursion with helper method and compare it to the non-tail recursion method. 

Explain 2nd order linear recursion using the example of Fibonacci sequence. 

Write an advanced Fibonacci number generator which can handle int data type and long data type.

Introduction of using recursion to solve problems.  One example of recursive palindrome check is used. 

Show the simple steps to write a recursive method. 

Recursive Information Processing I on Simple Statistics. 

Recursive Processing on Text Processing. 

Recursive Processing III on recursive algorithms. 

Comparison and conversion between iterative algorithm and recursive algorithm. 

Writing the Palindrome Check for String (a chance to rewrite the program that is shown in the lecture). Please try to write in a different way. 

Using mathematical definition of Fibonacci sequence to compare the efficiency of iterative algorithm and recursive algorithm. 

Tower of Hanoi algorithm. 

Overview of Algorithms and Algorithm study.  Introduce these important concepts and their study domain.

Discuss the Time complexity T(n) function and its asymptotic behavior for O(n) growth rate (for Big O notation)

Resume the Geometric Project Series with comparable interface (implements compareTo() method). 

Discuss how to formulate the time complexity function T(n) and the growth function O(n) which is the big-O notation. 

collection of algorithms for FRQ exams.  We provide programs to show the basic algorithms.  By studying these algorithms, you may use them with some modification in the free response section in the real exams. 

Use Euclid's algorithm to show that good algorithms do not come from hard-working people but from smart-working people.  A person cannot invent good algorithm by only studying other people's algorithm.  Instead, he must know about the nature of problem pretty well to invent a good algorithm. 

Use 4 different algorithm to demonstrate the Prime Number checking algorithm (isPrime) of different efficiency.  Because of this reason, finding a good algorithm is very important. 

Discuss simple linear search algorithm which is very useful in many applications. This lecture is followed by two exemplary demo program for letter occurrence count and word occurrence count in a text string.

Highlight the issues in the study of algorithms. 

Add the equals2D() method to the Geo2D interface, Rectangle3, Triangle3 classes. 

Add the equals3D() method to the Geo3D interface, Box3, Prism3 classes. 

Use these two methods to perform linear search on 2D and 3D Geometric objects. 

Introduce a Binary Search version which will return the index of the matched element or a return code which indicate the hole where the key element can be inserted.

Insertion Sort is based on finding the minimum and Insert by circular shifting. Example program is provided.

Showing the steps of a Insertion Sort case. 

Exercise on Insertion sort for array and use the same program to work on the arraylist with proper type conversion. 

Selection Sort is based on the idea of finding minimum and swap. This lecture discussed selection sort from idea to solution. And an example is given.

Showing the steps of a particular selection sort case. 

Exercise on Insertion sort for array and use the same program to work on the arraylist with proper type conversion. 

Demo the use of selection sort and the binary search for arraylist and array. The array and arraylist are of interface reference type.  Interfaces are used as a combination of heterogeneous data object types. 

Bubble Sort is another linear array sort. It is O(n^2) algorithm. The core for this algorithm is successive compare and swap.

Showing the steps of a particular Bubble Sort case. 

Bubble Sort is based on the idea of finding minimum and swap. This lecture discussed bubble sort from idea to solution. And an example is given.

Introduce the merge sort and its performance analysis

Merge Sort is based on the idea of finding minimum and swap. This lecture discussed merge sort from idea to solution. And an example is given.

Introduce quick sort algorithm with small pivot version and general discussion for quick sort performance. Extra links for the middle pivot and large pivot version are also provided.

Quick Sort is based on the idea of finding minimum and swap. This lecture discussed quick sort from idea to solution. And an example is given.

Collections Framework in Java API. 

Revisit for ArrayList by comparing ArrayList to LinkedList. 

Discuss the LinkedList Concrete Class

Word Ordering by Frequency using Linked List

Introduce Vector Class which is a synchronized version of ArrayList.  All of the methods for List can also be used for Vector.  But Vector has its own legacy methods. 

enum is a special numerical data type (It is defined like a class, while it behaves like a list). 

Summarize the Java Collection-List API and start the custom-designed MyArrayList Class. 

Un-guided Lab: Use only the methods from the Collections, List, ArrayList, and Arrays classes or interfaces to convert an array to its own reverse. 

Introduce a simple example for custom designed pointer for linked list. 

Talk about the implementation of LinkedList class (named MyLInkedList). 

Discuss the data structure of Stack and Queue and provide a pair of examples for implementation of Stack and Queue using ArrayList and LinkedList, respectively. 

Discuss PriorityQueue Class in Java API and a custom design PriorityQueue Class

Discuss the Stack Class and Queue Interface in the collections framework. 

Discussion of Map Interface, HashMap, LinkedHashMap, TreeMap Classes and SortedMap, NavigableMap Interfaces

Application of Map data structure by an example of counting the word occurrence.  Please compare to AP Computer Science A chapter 7 Bible Word Count. 

Introduction to Set Interface, HashSet, and LinkedHashSet Classes. 

Ordered TreeSet