Question

Task #1 Creating a New Class

1. In a new file, create a class definition called Television.

2. Put a program header (comments/documentation) at the top of the file

// The purpose of this class is to model a television

// Your name and today's date

3. Declare the 2 constant fields listed in the UML diagram.

4. Declare the 3 remaining fields listed in the UML diagram.

5. Write a comment for each field indicating what it represents.

6. Save this file as Television.java.

7. Compile and debug. Do not run.

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Task #2 Writing a Constructor

1. Create a constructor definition that has two parameters, a manufacturer's brand

and a screen size. These parameters will bring in information

2. Inside the constructor, assign the values taken in from the parameters to the

corresponding fields.

3. Initialize the powerOn field to false (power is off), the volume to 20, and the

channel to 2.

4. Write comments describing the purpose of the constructor above the method

header.

5. Compile and debug. Do not run.

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Task #3 Methods

1. Define accessor methods called getVolume, getChannel,

getManufacturer, and getScreenSize that return the value of the corresponding

field.

2. Define a mutator method called setChannel accepts a value to be stored in

the channel field.

3. Define a mutator method called power that changes the state from true to false

or from false to true. This can be accomplished by using the NOT operator (!).

If the boolean variable powerOn is true, then !powerOn is false and vice

versa. Use the assignment statement

powerOn = !powerOn;

to change the state of powerOn and then store it back into powerOn (remember

assignment statements evaluate the right hand side first, then assign the

result to the left hand side variable.

4. Define two mutator methods to change the volume. One method should be

called increaseVolume and will increase the volume by 1. The other

method should be called decreaseVolume and will decrease the volume by

1.

5. Write javadoc comments above each method header.

6. Compile and debug. Do not run.

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Task #4 Running the application

1. You can only execute (run) a program that has a main method, so there is a driver

program that is already written to test out your Television class. Copy

the file TelevisionDemo.java (see code listing 3.1) from www.aw.com/cssupport

or as directed by your instructor. Make sure it is in the same directory as

Television.java.

2. Compile and run TelevisionDemo and follow the prompts.

3. If your output matches the output below, Television.java is complete and correct.

You will not need to modify it further for this lab.

OUTPUT (boldface is user input)

A 55 inch Toshiba has been turned on.

What channel do you want? 56

Channel: 56 Volume: 21

Too loud!! I am lowering the volume.

Channel: 56 Volume: 15

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Task #5 Creating another instance of a Television

1. Edit the TelevisionDemo.java file.

2. Declare another Television object called portable.

3. Instantiate portable to be a Sharp 19 inch television.

4. Use a call to the power method to turn the power on.

5. Use calls to the accessor methods to print what television was turned on.

6. Use calls to the mutator methods to change the channel to the user's preference

and decrease the volume by two.

7. Use calls to the accessor methods to print the changed state of the portable.

8. Compile and debug this class.

9. Run TelevisionDemo again.

10. The output for task #5 will appear after the output from above, since we added

onto the bottom of the program. The output for task #5 is shown below.

OUTPUT (boldface is user input)

A 19 inch Sharp has been turned on.

What channel do you want? 7

Channel: 7 Volume: 18

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Code Listing 6.1 (TelevisionDemo.java)

import java.util.Scanner;

/** This class demonstrates the Television class*/

public class TelevisionDemo

{

public static void main(String[] args)

{

//create a Scanner object to read from the keyboard

Scanner keyboard = new Scanner (System.in);

//declare variables

int station; //the user's channel choice

//declare and instantiate a television object

Television bigScreen = new Television("Toshiba", 55);

//turn the power on

bigScreen.power();

//display the state of the television

System.out.println("A " + bigScreen.getScreenSize() +

bigScreen.getManufacturer() +

" has been turned on.");

//prompt the user for input and store into station

System.out.print("What channel do you want? ");

station = keyboard.nextInt();

//change the channel on the television

bigScreen.setChannel(station);

//increase the volume of the television

bigScreen.increaseVolume();

//display the the current channel and volume of the

//television

System.out.println("Channel: " +

bigScreen.getChannel() +

" Volume: " + bigScreen.getVolume());

System.out.println(

"Too loud!! I am lowering the volume.");

//decrease the volume of the television

bigScreen.decreaseVolume();

bigScreen.decreaseVolume();

bigScreen.decreaseVolume();

bigScreen.decreaseVolume();

bigScreen.decreaseVolume();

bigScreen.decreaseVolume();

//display the current channel and volume of the

//television

System.out.println("Channel: " +

bigScreen.getChannel() +

" Volume: " + bigScreen.getVolume());

System.out.println(); //for a blank line

//HERE IS WHERE YOU DO TASK #5

}

}

Answer 1

Dear,

// Television Class

// The purpose of this class is to model a television
// Your name and today's date
public class Television {

    private final String MANUFACTURER ; //manufacturer of the TV
    private final int SCREEN_SIZE ; //Screen size of the TV
    private boolean powerOn;    //power on/off button
    private int channel;    //channel
    private int volume;     //volume to increase/decrease

    //two arguments constructor initializes all the attributes of the
    //television class
    public Television(String manu,int screen){
        MANUFACTURER = manu;
        SCREEN_SIZE = screen;
        powerOn = false;
        volume = 20;
        channel = 2;       
    }

    //returns the current volume
    public int getVolume(){
        return volume;
    }
    //return the current channel
    public int getChannel(){
        return channel;
    }
    //returns the manufacturer of the TV
    public String getManufacturer(){
        return MANUFACTURER;
    }
    //returns the screen-size
    public int getScreenSize(){
        return SCREEN_SIZE;
    }
    //sets the channel to a given number
    public void setChannel(int ch){
        channel=ch;
    }
    //sets the TV power on/off
    public void power(){
        powerOn = !powerOn;
    }
    //increases the TV volume by 1
    public void increaseVolume(){
        volume+=1;
    }
    //decreases the TV volume by 1
    public void decreaseVolume(){
        volume-=1;
    }
} //end of the Television class


// TelevisionDemo.java

import java.util.Scanner;

/** This class demonstrates the Television class*/
public class TelevisionDemo {

    public static void main(String[] args) {

        //create a Scanner object to read from the keyboard
        Scanner keyboard = new Scanner(System.in);
        //declare variables
        int station; //the user's channel choice
        //declare and instantiate a television object
        Television bigScreen = new Television("Toshiba", 55);
        //turn the power on
        bigScreen.power();
        //display the state of the television
        System.out.println("A " + bigScreen.getScreenSize() + " inch "+
                bigScreen.getManufacturer() +
                " has been turned on.");

        //prompt the user for input and store into station

        System.out.print("What channel do you want? ");

        station = keyboard.nextInt();
        //change the channel on the television
        bigScreen.setChannel(station);
        //increase the volume of the television
        bigScreen.increaseVolume();
        //display the the current channel and volume of the
        //television
        System.out.println("Channel: " +
                bigScreen.getChannel() +
                " Volume: " + bigScreen.getVolume());

        System.out.println(
                "Too loud!! I am lowering the volume.");

        //decrease the volume of the television
        bigScreen.decreaseVolume();
        bigScreen.decreaseVolume();
        bigScreen.decreaseVolume();
        bigScreen.decreaseVolume();
        bigScreen.decreaseVolume();
        bigScreen.decreaseVolume();

        //display the current channel and volume of the
        //television
        System.out.println("Channel: " +
                bigScreen.getChannel() +
                " Volume: " + bigScreen.getVolume());

        System.out.println(); //for a blank line

        //HERE IS TASK #5
        Television portable=new Television("Sharp", 19);
        portable.power();

        //display the state of the television
        System.out.println("A " + portable.getScreenSize() + " inch "+
                portable.getManufacturer() +
                " has been turned on.");

        //prompt the user for input and store into station
        System.out.print("What channel do you want? ");

        station = keyboard.nextInt();
        //change the channel on the television
        portable.setChannel(station);
        //decrease the volume of the television.
        portable.decreaseVolume();
        portable.decreaseVolume();

        //display the current channel and volume of the
        //television

        System.out.println("Channel: " +
                portable.getChannel() +
                " Volume: " + portable.getVolume());
    }
}

Output:

run:
A 55 inch Toshiba has been turned on.
What channel do you want? 56
Channel: 56 Volume: 21
Too loud!! I am lowering the volume.
Channel: 56 Volume: 15

A 19 inch Sharp has been turned on.
What channel do you want? 7
Channel: 7 Volume: 18
BUILD SUCCESSFUL (total time: 12 seconds)