Commander - Interfacing Prevayler

AppendChar.java

  class AppendChar implements Transaction<Appendable> {
    private final char c;
    public AppendChar(char c) {
      this.c = c;
    }
    public void executeOn(Appendable prevalentSystem, Date executionTime) {
      prevalentSystem.append(c);
    }
  }

  prevayler.execute(new AppendChar('x'));
  prevayler.execute(new AppendChar('y'));
  prevayler.execute(new AppendChar('z'));