Scoring Rubric (9 points)

Solution

public class SignedText
{
    private String firstName;
    private String lastName;

    public SignedText(String first, String last)
    {
        firstName = first;
        lastName = last;
    }

    public String getSignature()
    {
        String sig = "";

        if (!firstName.equals(""))
        {
            sig += firstName.substring(0, 1) + "-";
        }

        sig += lastName;
        return sig;
    }

    public String addSignature(String textStr)
    {
        String sig = getSignature();
        int index = textStr.indexOf(sig);

        if (index == -1)
        {
            return textStr + sig;
        }
        else if (index == 0)
        {
            return textStr.substring(sig.length()) + sig;
        }
        else
        {
            return textStr;
        }
    }
}

Step-by-Step: Constructor

Step 1: Declare the class with public class SignedText.

Step 2: Declare two private String instance variables for the first and last names.

Step 3: Write the constructor to assign the parameters to the instance variables. This is straightforward — just firstName = first; lastName = last;.

Step-by-Step: getSignature

Step 4: Check if firstName is empty using .equals(""). Do not use == to compare Strings in Java.

Step 5: If the first name is not empty, build the signature as: first character of firstName + "-" + lastName. Use substring(0, 1) to get the first character.

Step 6: If the first name is empty, the signature is just the lastName.

Step-by-Step: addSignature

Step 7: Call getSignature() to get the signature string. You must call the method — do not rebuild the signature logic.

Step 8: Use indexOf(sig) to find where (if anywhere) the signature appears in the text.

Step 9: Three cases:

• indexOf returns -1: signature not found → append it to the end.
• indexOf returns 0: signature is at the beginning → remove it from the front, append to end.
• Otherwise: signature is already at the end → return the text unchanged.

Alternate Approach (Single Instance Variable)

public class SignedText
{
    private String signature;

    public SignedText(String first, String last)
    {
        signature = last;
        if (first.length() > 0)
        {
            signature = first.substring(0, 1) + "-" + last;
        }
    }

    public String getSignature()
    {
        return signature;
    }

    public String addSignature(String textStr)
    {
        int index = textStr.indexOf(signature);
        String result = textStr;

        if (index < 0)
        {
            result += signature;
        }
        else if (index == 0)
        {
            result = result.substring(signature.length()) + signature;
        }

        return result;
    }
}

This alternate uses a single signature field computed in the constructor. Both approaches earn full credit.