Question

This assignment is designed to give you practice with Javadoc, creating unit tests and using Junit.

Be sure to follow all style and documentation requirements for THIS class. See the style and documentation requirements posted on Canvas.

You are to name your package assign1 and your file Palindrome.java.

Palindrome Class

Palindrome

testString : String

+ Palindrome (String) + isPalindrome (): boolean

The method isPalindrome is to determine if a string is a palindrome. A palindrome, for this assignment, is defined as a word or phrase consisting of alphanumeric characters that reads the same frontwards and backwards while ignoring cases, punctuation and white space. If there are nt alphanumeric characters, it is considered a palindrome. The method should return true if it is a palindrome and false otherwise.

For this assignment, you are limited to the following Java library classes.

• Scanner
• String
• Character

Here are the restrictions on this method. Up to 20% penalty if not followed.

1. You may NOT return from the inside of a loop.
2. You may NOT break from the inside of a loop.
3. You may use ONLY ONE loop (either while or do-while).
4. You may NOT copy the String to another String.
5. You may NOT process the String more than one time (only make one pass through it).
6. You must STOP processing as early as possible (when you find that it is or is not a palindrome). In other words, using a for loop is not a good solution.

Testing

1. Generate the initial set of junit test cases. All should have the initial result of “fail”. This will create the file “PalindromeTest.java”. There is an example of creating junit tests in the PowerPoint slides with this assignment. This process may vary with your version of Java.

2. Feel free to work with the teaching assistant to help with this process. In addition, there are a lot of tutorials online to help you. Here are a couple of sources I found.
   • https://www.youtube.com/watch?v=LPPji9JESgQ
   • https://www.vogella.com/tutorials/JUnit/article.html

3. Complete the code for your test cases. Create new methods as needed for different tests. Your tests should not have any if statements, loops or output. Use the asserts to check the results. Test your code.

4. Make sure that all the code meets all coding and documentation standards. The junit test cases should include internal documentation while the OrderedIntList.java file should contain external documentation.

Submitting

Using the link on Canvas, submit your Palindrome.java file and your PalindromeTest.java file for grading. These will be downloaded, compiled and graded as well as checked for plagiarism and similarity to other students’ work.

Grading

Creation of junit tests – only if the code compiles                 25%

Coding style and documentation – only if code compiles     20%

Results from tests – only if code compiles                             55%

Note: Your test file must be submitted but your code will be tested using other tests.

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

// Palindrome.java

public class Palindrome {

      private String testString;

      public Palindrome(String testString) {

            // assigning testString in lower case if it is not null

            if (testString != null)

                  this.testString = testString.toLowerCase();

      }

      public boolean isPalindrome() {

            if (testString == null) {

                  // test string is null (not empty). it should be invalid

                  return false;

            }

            // assuming string is palindrome

            boolean isPal = true;

            // creating variables to store indices of first and last characters

            int frontIndex = 0, rearIndex = testString.length() - 1;

            char c1, c2; // to store characters

            // loops as long as isPal is true and front index is smaller than

            // rearIndex

            while (isPal && frontIndex < rearIndex) {

                  // getting characters at both indices

                  c1 = testString.charAt(frontIndex);

                  c2 = testString.charAt(rearIndex);

                  // if c1 is not alphanumeric, just incrementing front index

                  if (!Character.isLetterOrDigit(c1)) {

                        frontIndex++;

                  }

                  // if c2 is not alphanumeric, just decrementing rear index

                  if (!Character.isLetterOrDigit(c2)) {

                        rearIndex--;

                  }

                  // if both are alphanumeric, comparing them

                  if (Character.isLetterOrDigit(c1) && Character.isLetterOrDigit(c2)) {

                        if (c1 != c2) {

                              // both are different, the loop wont run for next time

                              isPal = false;

                        } else {

                              // incrementing front index, decrementing rear index

                              frontIndex++;

                              rearIndex--;

                        }

                  }

            }

            // returns the value of isPal

            return isPal;

      }

}

// PalindromeTest.java

import static org.junit.Assert.*;

import org.junit.Test;

public class PalindromeTest {

      @Test

      public void testNormal() {

            // testing Palindrome using simple alphabetical words

            Palindrome p = new Palindrome("Hannah");

            assertTrue(p.isPalindrome());

            p = new Palindrome("Java");

            assertFalse(p.isPalindrome());

            p = new Palindrome("maLayalam");

            assertTrue(p.isPalindrome());

      }

      @Test

      public void testSpecialSymbols() {

            // testing Palindrome using Strings containing special symbols and

            // spaces

            Palindrome p = new Palindrome("ha n%n&a()h//;;");

            assertTrue(p.isPalindrome());

            p = new Palindrome("r...ace cAr");

            assertTrue(p.isPalindrome());

      }

      @Test

      public void testDigits() {

            // testing Palindrome using Strings containing digits

            Palindrome p = new Palindrome("hannah990");

            assertFalse(p.isPalindrome());

            p = new Palindrome("racecar88188racecar");

            assertTrue(p.isPalindrome());

      }

      @Test

      public void testEmpty() {

            // testing Palindrome using Strings containing empty string

            Palindrome p = new Palindrome("");

            assertTrue(p.isPalindrome());

      }

      @Test

      public void testSentences() {

            // testing Palindrome using Strings containing long sentences

            Palindrome p = new Palindrome("Madam I'm Adam");

            assertTrue(p.isPalindrome());

            p = new Palindrome("Sit on a potato pan, Otis");

            assertTrue(p.isPalindrome());

            p = new Palindrome("Able was I, ere I saw Elba");

            assertTrue(p.isPalindrome());

            p = new Palindrome("Nope! This is not a palindrome");

            assertFalse(p.isPalindrome());

      }

}

/*OUTPUT of JUnit test*/

Runs: 5/5 Errors: 0 Failures: 0 palindrome.PalindromeTest [Runner: JUnit 4] (0.0 testNormal (0.000 s) testSpecialSymbols (0.000 s) testDigits (0.000 s) testEmpty (0.000 s) testSentences (0.000 s)