ENSF-593 Assignment 1

An assignment on practice designing and implemented classes, using objects in Java.

This assignment has two mandatory parts:

• 1. Temperature
• 2. Tile

and two optional parts (not graded):

• Enhanced Temperature
• Rational

1. Temperature

Problem Statement

Design and implement a class for a Temperature object that is capable of reporting its temperature in either Fahrenheit or Celsius. This class should have one instance variable called degrees, which contains the Fahrenheit temperature, and two public methods, one called getFahrenheit(), which returns the temperature in Fahrenheit, and one called getCelsius(), which returns the temperature in Celsius. This method has to convert the stored temperature to Celsius before returning it. An expression for converting Fahrenheit to Celsius is (5 *(F -32) /9), where F is the temperature in Fahrenheit. Test your class definition by implementing a main() method that creates Temperature instances and displays their temperature values.

Your program should produce the following output in the Java console:

 The Fahrenheit temperature of thermometer1 is 20.0 degrees.
 The Celsius temperature of thermometer1 is -6.67 degrees.
 The Fahrenheit temperature of thermometer2 is 98.6 degrees.
 The Celsius temperature of thermometer2 is 37.0 degrees.

Problem Decomposition

This problem can be divided into one class, the Temperature class, which will implement the temperature conversion. It will contain a main() method in which Temperature instances will be created and used.

Design

1. Draw a UML class diagram to describe the design of the Temperature class. Your design should identify the name of the class, its attributes (instance variables) and behaviors (methods). Designate which elements will be hidden and which parts of the class will make up its public interface. Model your design after the the Riddle class discussed in Chapter 1 of Java, Java, Java, 3E.

2. Develop a written specification for the Temperature class based on your UML diagram. This will become a comment block at the beginning of your source file.

3. Type the specification you developed in Step 2 into a Java comment block in src/Temperature.java. This file will be the file you use for defining the Temperature class. The comment will serve as documentation for the program. A comment block in Java begins with either /* or /** and ends with */. It can extend over multiple lines. As explained in Appendix A, comments that begin with /** are documentation comments, which can be automatically turned into documentation for the class by using software that comes with the Java Development Kit (JDK). You should use documentation comments to describe a class's specification. Here's an example format that you can use:

/**
* Class Name: Circle
*
* ... ( the rest of your specification )
*
*/

You find more Java documentation examples in JavaDocumentationGuidelines.pdf on D2L.

Implementation

Use the stepwise refinement approach to code and test the Temperature class. Here's a sequence of appropriate steps, after each of which you should compile and run your program. Step 4, step 5 and step 6 are good points to commit to git.

1. Code the initial comment block (purpose of your program, author name, etc) and the basic class definition.

2. Code the declarations for the class's instance variables as well as the constructor method.

3. Code the definition for each method, one at a time.

4. Code a stub version of the main() method.

5. Add code to the main method to create and use one Temperature object. Write one access method at a time, as well as a method call in main() that tests the method. Here is where you would use method calls embedded within println() expressions to display the temperature values. For example, here are several statements that will output thermometer1's temperature:

System.out.print("The Fahrenheit temperature of  thermometer1 is  ");
System.out.print(thermometer1.getFahrenheit());
System.out.println(" degrees.");

6. Add code to the main method to create and use a second Temperature object.

Reporting In the markdown file Temperature.md add the UML class diagram you drew as an embedded image. Include a screenshot demonstrating successful execution and outputs.

2. Tile

Problem Statement

In the board game Scrabble, each tile contains a letter, which is used to spell words in rows and columns, and a score, which is used to determine the value of words.

Design and implement a class for a Tile object that represents Scrabble tiles. The instance variables should include a character named letter and an integer named value. A character can be defined with char letter = 'A'; in Java. Character variables can be compared with ==, similar to other primitive types.

In addition to the default constructor that initializes letter to 'A' and value to 1, add a constructor that takes two arguments to initialize instance variables.

The Tile class should override the methods toString() and equals() from the parent class Object. Note that toString() is automatically called when an object is passed to println(). To compare two objects use o1.equals(o2).

Test your class definition by implementing a main() method that creates Tile instances and displays their letter and value. Include an example where two tiles are equal, and two tiles are not equal.

Your program should produce the following output in the Java console:

Tile 0: A[1]
Tile 1: A[1]
Tile 2: Z[10]
Tile 0 is equal to Tile 1 is true
Tile 0 is equal to Tile 2 is false

Problem Decomposition

This problem can be divided into one class, the Tile class, which will implement the Tile representation and comparison logic. It will contain a main() method in which Tile instances will be created and used.

Design

1. Draw a UML class diagram to describe the design of the Tile class. Your design should identify the name of the class, its attributes (instance variables) and behaviors (methods). Designate which elements will be hidden and which parts of the class will make up its public interface.

2. Develop a written specification for the Tile class based on your UML diagram. This will become a comment block at the beginning of your source file.

3. Type the specification you developed in Step 2 into a Java comment block in src/Tile.java. This file will be the file you use for defining the Tile class. The comment will serve as documentation for the program.

Implementation

Use the stepwise refinement approach to code and test the Tile class. Here's a sequence of appropriate steps, after each of which you should compile and run your program. Step 4, step 5, step 6 and step 7 are good points to commit to git.

1. Code the initial comment block (purpose of your program, author name, etc) and the basic class definition.

2. Code the declarations for the class's instance variables as well as the constructor method.

3. Code the definition for each method, one at a time.

4. Code a stub version of the main() method.

5. Add code to the main method to create and use one Tile object. Write constructors one at a time, as well as a corresponding instantiation in main() that tests the constructor.

6. Write toString() and add code to main() to test it.

7. Write equals() and add to main() to test it.

Reporting In the markdown file Tile.md add the UML class diagram you drew as an embedded image. Include a screenshot demonstrating successful execution and outputs.

Optional: Enhanced Temperature

Copy src/Temperature.java to src/EnhancedTemperature.java and adapt the code to run with the new class name.

Add two mutator methods setFahrenheit() and setCelsius() to set the Temperature instance variable. Each method has a parameter representing temperature in the corresponding unit, Fahrenheit or Celsius.

Add code to main() that asks the user to enter a temperature and prints the conversion. The user should be able to define the units first, then enters the temperature, finally, the program prints the corresponding temperature in the other unit. Use the Scanner class introduced in section 2.6 in Java, Java, Java 3E.

As a further extension, the main() could continue asking for conversions until the user enters 'q' for quit.

Optional: Rational

Solve Exercise 11.4 in ThinkJava 2e available https://greenteapress.com/wp/think-java-2e/