The class EncryptedText: public interface

We can now choose the interface of the class, through which the clients can make use of the objects of the class EncryptedText.

Specifically, for each functionality we have to define a public method that realizes it and determine its header.

This leads us to the following skeleton for the class EncryptedText:

public class EncryptedText {
  // representation of the objects of the class
  private int key;
  private String text;

  // constructor
  public EncryptedText(String nonEncryptedText) {
         ...
  }
  public EncryptedText(String nonEncryptedText, int key) {
    ...
  }
  // other public methods
  public String getEncryptedText() {
         ...
  }
  public String getDecryptedText(int key) {
         ...
  }
  public boolean isKey(int candidateKey) {
         ...
  }
  public void setKey(int key, int newKey) {
         ...
  }

  // possibly auxiliary methods
}