Introduction to Programming
Java Programming Assignment: Objects and Decisions
Your last Alice program implemented decision making.
This assignment will apply the same concepts to Java, starting with the code from your last Java program (Java Assn 4), which implemented objects. The Java Assn 4 program ran all of the code sequentially.
Decision statements will now be used to run some of the statements conditionally, by implementing at least one of each of the following conditional programming constructs: if statement or if/else statement, multiple alternative if statement, nested if statement, and switch statement.
WARNING: Again, this assignment will be more challenging than the previous assignments, so make sure to start early and allocate enough time to complete it, including time you might need to seek any necessary help.
Problem Summary
Suppose you wanted to further modify your Mortgage Calculator, to make it more versatile. Starting with Java programming assignment 4, you could add the following features:
• Let the user decide on the down payment percentage amount to use.
• Calculate and display mortgage payments for both a 20-year and a 30-year loan, to allow the user to compare them.
• Have the program use the mortgage company's guidelines to set the interest rate for a mortgage.
o The mortgage company sets interest rates using the following chart, based on the length of a loan and the loan type.
o Loans up to $417,000 are called "conforming" loans. Loans over that amount are considered "jumbo" loans, and have different interest rates.
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Interest Rate Chart
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Conforming Loans
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Jumbo Loans
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30-year fixed
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4.5%
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4.125%
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20-year fixed
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3.85%
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3.5%
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Overview of Program
This program will still contain two classes, in two separate files within your project:
• A modified MortgageLoan class to define the data fields and methods for a MortgageLoan object, containing:
o Seven data field definitions for a MortgageLoan object
o Two constructor methods to create a MortgageLoan object (one constructor without parameters and one constructor with parameters).
o Six setter methods to set the values for six of the data fields
o An instance method to compute the monthly property tax.
o An instance method to compute the monthly insurance premium.
o An instance method to compute the monthly principle and interest loan payment.
o An instance method to display one loan's information.
o An instance method to calculate and display a loan's payment information.
• The main MortageCalculator class, modified to define only two methods, containing:
o A static method to display a description of what the program will do.
o A main method to display the program description, to read the inputs from the user, to create two MortgageLoan objects, and to call the other methods to display loan and payment information.
Program Requirements
Modify the program you wrote for Java Assignment 4, as follows:
1. Within the MortgageLoan class:
• Add the following additional private data field:
o char loan type (will store ‘C' for conforming or ‘J' for jumbo)
• Add a setter for the loan type data field. This method will:
o Define a local constant and set it to hold the upper limit for conforming loan amounts.
o Set the loan type data field to ‘C' for Conforming.
Then use an if statement to decide whether to re-set the data field to ‘J' for Jumbo, depending upon the value stored in the loan amount data field.
• Modify the setter for the loan identifier data field.
o The setter will now only have one parameter, the last name (will no longer use the zip code).
o The loan identifier field will be created using the first 6 letters (uppercased) of the last name.
- If the last name has less than 6 letters, the code should append Xs to the end of the name, so that there will be 6 letters total.
o Modify the body of the setter method to:
- Declare an integer constant to hold the loan identifier's String length of 6.
- Declare a second String constant to hold six Xs ("XXXXXX").
- Use these constants and the last name to create the loan identifier, WITHOUT using brute force.
o NOTE: You will need to check the length of the last name BEFORE trying to extract letters and then use a decision statement to decide which letters to extract. Otherwise the program may crash when there are less than 6 letters in the last name.
• Modify the setter for the loan annual interest rate
o The user will no longer enter the annual interest rate. Instead, the setter will use a nested if statement to set the annual interest rate data field, according to the chart on the previous page.
• Check the loan type data field.
• If the loan is a conforming loan, decide which rate to use based rates for conforming loans and the loan length data field.
• Otherwise, decide which rate to use based rates for jumbo loans and the loan length data field.
• Modify the setter for the down payment percent
o Add a char input parameter, to pass in the user's letter choice of down payment.
o Use a switch statement to set the down payment percentage as follows: N (no down payment) - set the percentage to 0
L (low down payment) - set the percentage to 10%
S (standard down payment) - set the percentage to 20% H (high down payment) - set the percentage to 30%
If the parameter contains any other letter, set the percentage to 0, and display an error message telling the user that since his/her choice was invalid, no down payment will be applied.
• Add a second constructor to instantiate a MortgageLoan type object. The new constructor with have four parameters:
o the home buyer's last name (String)
o the home value
o the down payment percentage choice (char)
o the loan length in years The constructor will:
o Assign values to the home value and loan length data fields, using the constructor parameters for the values.
o Call the modified setters for the loan identifier and the down payment percent, using the constructor parameter as the setter arguments.
o Call the original setter for the loan amount (no arguments - uses data fields values)
o Call the new setter for the loan type (no arguments - uses data field values).
o Call the modified setter for the loan annual interest rate (no arguments - uses data field values.
NOTE: The original getters for this class will no longer be necessary. All data fields will be accessed via the display instance methods.
• Modify the method that computes the insurance premium, so that it will decide what insurance rate to use.
o Instead of using a constant insurance rate (delete the defined constant), use a multiple alternative if statement to decide what rate to use, based on the down payment percentage, and store the value into a variable.
- For down payments of 10% or less, use a rate of 0.52%
- For down payments over 10%, up to 20%, use the rate from assignment 3 (0.49%).
- For down payments over 20%, use a rate of 0.47%.
• Convert the two static display methods from Java Assn 4 to be two instance methods within the
MortgageLoan class, as described below.
o Note that neither of these methods will require parameters, because the data fields can be accessed directly.
• The first instance method, displayLoanInfo, will:
o Display only the loan identifier, the loan amount and loan type.
- The loan amount should be displayed to 2 decimal places
- Use an if/else statement to display the loan type.
- Display "conforming" when the loan type is ‘C'
- Otherwise, display "jumbo"
- All values should line up with each other on the right, as shown below:
• The second instance method, calcAndDisplayPaymentInfo, will:
o Call each of the calculation instance methods (to compute the monthly taxes, insurance, and loan principle & interest payments) using this so that the calculations methods calls will use the same object as the calcAndDisplayPaymentInfo method.
- Save the results returned from the calls to each calculation method, and then compute the total monthly mortgage payment.
o Modify the display of the loan length, annual interest, and monthly mortgage payment parts and total, to look like this:
- Each of these lines should be indented by 2 spaces
- The loan length should be displayed in whole years.
- The annual interest rate should be displayed to 3 decimal places and be followed by a percent sign (%).
- All dollar figures should be displayed to 2 decimal places, lined up on the decimal points.
- All values should line up with each other on the right, and also line up with the loan identifier, amount, and type displayed from the displayLoanInfo method.
After creating the above two instance methods, be sure to delete the static display methods from the
MortgagCalculator class.
2. Within the original class MortgageCalculator class that contains the main method:
• Modify the main method to:
o Still display the program description, as in Java Assignment 4.
o Modify what data is read from the user.
- Read the home buyer's last name, as in Java Assignment 4.
- Remove the code that reads the zip code.
- Read the home value, as in Java Assignment 4.
- Remove the code that reads the annual percentage rate from the user.
- Read the down payment choice (as shown in the Sample Inputs below), as follows:
• Display a menu to the user, with letters as choices.
• Prompt for the user's choice, and read the letter chosen by the user.
Debugging and Testing
Run, test, and debug your Java program, until you confirm that all of the decision control structures work. Be sure to test your program with different inputs to make sure it provides correct results.
Submission
This programming assignment is due by midnight of the date listed in the Course Assignments by Week.
Again, you will submit a single zip file containing all of the files in your project.
• First export your project from NetBeans:
o Highlight the project name.
o Click on File from the top menu, and select Export Project.
o Select To ZIP
o Name your export file in the following format:
Assn.zip
For example:
SmithAssn5.zip
NOTE: Save this zip file to some other directory, not your project directory.
• Then submit your .zip file to the Java Prog Assn 5 assignment submission folder (located under the Assignments/Dropbox tab in the online course).
o Warning: Only NetBeans export files will be accepted.
Do not use any other kind of archive or zip utility.
Attachment:- Java Porgram.rar