Problem Set 5: Water Meter

Task Outline

• Due Date: Wednesday, October 16, 2019
• Total Points: 10
• Implement a Java program that calculates the amount of money that a customer will be billed, based on their water usage.

Background Theory

• A water utility is responsible for supplying clean, fresh water to its customers in a given geographical area.
• The water utility will typically charge different rates for each category of customer. Supplying water to individual households is relatively straightforward, so they are charged minimal rates. However, commercial and industrial factories may require massive amounts of water, so they are charged more for the necessary supporting infrastructure.
• A customer's water bill depends on how many gallons of water they consumed during a particular billing period.
• A water meter is used to determine a customer's water consumption. It consists of a dial that has nine digits. However, note that the final digit in the dial records one-tenth of a gallon.
• In other words, if the water meter reads 923874345 then this corresponds to 92387434.5 gallons.
• The water meter is read once at the beginning of the billing period, and then once and the end. A customer's water consumption, in gallons, is computed from the difference in these two meter readings.

Customer Categories

• There are three categories of customer: residential, commercial, and industrial. The following is the fee schedule for each of these categories:

residential

• A base rate of $5.00, plus $0.0005 per gallon used.

commercial

• A base rate $1000.00 for 40000 gallons or less, plus $0.00025 for each additional gallon used.

industrial

• A base rate of $1000.00 for 40000 gallons or less. A base rate of $2000.00 if usage exceeds 40000 gallons, but does not exceed 80000 gallons. A base rate of $3000.00 plus $0.00025 for each additional gallon if usage exceeds 80000 gallons.

Hints

• Note that the meter's dial has nine digits and records the tenths of a gallon. For example, if the beginning reading was 444400003 and the ending reading was 444400135, then the customer used 13.2 gallons of water during that billing period.
• We won't consider the case where the water meter "flips over" from 999999999 to 000000000.

Code Distribution

Description	File Size	File Name
Java Source Code for Water Meter	1.4KB	pset05.zip

Contents of pset05.zip:

PSet05WaterMeter/
├── package.bluej
├── README.TXT
├── WaterBilling.class
├── WaterBilling.ctxt
├── WaterBilling.java
├── WaterBillingJUnitTest.class
├── WaterBillingJUnitTest.ctxt
└── WaterBillingJUnitTest.java

Specification

• Write a Java program in the file WaterBilling.java that determines the amount of money that a customer must pay for their water usage during a particular billing period.
• You will write your solution in a function called calculateBill(String customer, double begin, double end) right below the place where it says: YOUR CODE HERE
• When the function call calculateBill("residential", 444400003, 444400135) is executed, the output of the program should be: 5.0066

Testing

• Click on the Run Tests button to execute the JUnit test bench. JUnit indicates a successful test with a green bar, and an unsuccessful test with a red bar.

Submission

• Upload the file WaterBilling.java to the Web-CAT automated grading platform.