Make equals overridable to support different comparison logic

[gliechtenstein]

Adding an override-able "equals" method enables you to switch out comparison logic.

I love the look and feel of the library but one of my top priorities is security, so I wanted to encrypt the passcode before saving, and then later use the encrypted user input to compare the two.

Instead of building the encryption into the library I thought a better approach is to just expose the comparison method so that the inherited classes can override it.

For example I'm already using a library called SecurePreferences--which makes it easy to implement an encrypted version of SharedPreferences--in my project. So I simply need to extend PasscodeView and override the equals method. The end result looks something like this:

First, override the listener so that it encrypts the passcode before saving:

passcodeView.setListener(new PasscodeView.PasscodeViewListener() {
  @Override
  public void onFail() {
  }

  @Override
  public void onSuccess(String number) {
    String encrypted = SecurePreferences.hashPrefKey(raw);
    SharedPreferences.Editor editor = keys.edit();
    editor.putString("passcode", encrypted);
    editor.commit();
    finish();
  }
});

Second, compare using the overridden equals() method:

class PView extends PasscodeView {
  public PView(Context context) {
    super(context);
  }
  @Override protected Boolean equals(String psd) {
    String after = SecurePreferences.hashPrefKey(raw);
    return after.equals(encrypted_passcode);
  }
}
PView passcodeView = new PView(PasscodeActivity.this);

So far it's working fine for me without having to change much to the original library. What do you think?