Simple Encryption Code help. Why this error?

Question

Why does the implements Command pharse error this program out
I am a beginner here so please take it easy. I know it's probably a stupid mistake.
Also how would I limit the ASCII character conversion to be between 32 and 126.
public class Caesar {
implements Command //This line errors out the entire code
// Inv: true
private int shift;
public Caesar(int shift)
this.shift = shift;
public String encrypt(String text)
return shiftCharacterValues(text, shift);
public String decrypt(String text)
return shiftCharacterValues(text, -shift);
private String shiftCharacterValues(String text, int shift)
StringBuffer encrypted;
encrypted = new StringBuffer(text);
for (int i = 0; i < encrypted.length(); i++)
encrypted.setCharAt(i, (char)(encrypted.charAt(i) + shift));
return encrypted.toString();
public static void main(String[] args)
Caesar caesar;
String original, encrypted, decrypted;
caesar = new Caesar(7);
original = "hello"'
encrypted = caesar.encrypt(original);
decrypted = caesar.decrypt(encrypted);
System.out.println("Original = " + original);
System.out.println("Encrypted = " + encrypted);
System.out.println("Decrypted = " + decrypted);
}

Answer 1

might be?
public class Caesar {
  private int shift;
  public Caesar(int shift) {
    this.shift = shift;
  public String encrypt(String text) {
    return shiftCharacterValues(text, shift);
  public String decrypt(String text) {
    return shiftCharacterValues(text, -shift);
  private String shiftCharacterValues(String text, int shift) {
    StringBuffer encrypted;
    encrypted = new StringBuffer(text);
    for (int i = 0; i < encrypted.length(); i++)
         encrypted.setCharAt(i, (char)(encrypted.charAt(i) + shift > 126 ? (encrypted.charAt(i) + shift -95) : (encrypted.charAt(i)+shift < 32 ? (encrypted.charAt(i) + shift + 95) : encrypted.charAt(i) + shift)));
    return encrypted.toString();
  public static void main(String[] args) {
    Caesar caesar;
    String original, encrypted, decrypted;
    caesar = new Caesar(-7);
    original = " hello";
    encrypted = caesar.encrypt(original);
    decrypted = caesar.decrypt(encrypted);
    System.out.println("Original = " + original);
    System.out.println("Encrypted = " + encrypted);
    System.out.println("Decrypted = " + decrypted);
}