整理：J2SE5枚举使用范例

一、 定义枚举
public enum Grade {
  A, B, C, D, F, INCOMPLETE
};

二、遍历枚举值
public void listGradeValues(PrintStream out) throws IOException {
  for (Grade g : Grade.values()) {
    out.println("Allowed value: '" + g + "'");
  }
}

三、在switch中使用enum
public void testSwitchStatement(PrintStream out) throws IOException {
  StringBuffer outputText = new StringBuffer(student1.getFullName());

  switch (student1.getGrade()) {
    case A:
      outputText.append(" excelled with a grade of A");
      break;  
    case B: // fall through to C
    case C:
      outputText.append(" passed with a grade of ")
                .append(student1.getGrade().toString());
      break;
    case D: // fall through to F
    case F:
      outputText.append(" failed with a grade of ")
                .append(student1.getGrade().toString());
      break;
    case INCOMPLETE:
      outputText.append(" did not complete the class.");
      break;
    default:
      outputText.append(" has a grade of ")
                .append(student1.getGrade().toString());
      break;
  }

  out.println(outputText.toString());
}


四、联合使用枚举和集合
public enum AntStatus {
  INITIALIZING,
  COMPILING,
  COPYING,
  JARRING,
  ZIPPING,
  DONE,
  ERROR
}

public void testEnumMap(PrintStream out) throws IOException {
  // Create a map with the key and a String message
  EnumMap<AntStatus, String> antMessages =
    new EnumMap<AntStatus, String>(AntStatus.class);

  // Initialize the map
  antMessages.put(AntStatus.INITIALIZING, "Initializing Ant...");
  antMessages.put(AntStatus.COMPILING,    "Compiling Java classes...");
  antMessages.put(AntStatus.COPYING,      "Copying files...");
  antMessages.put(AntStatus.JARRING,      "JARring up files...");
  antMessages.put(AntStatus.ZIPPING,      "ZIPping up files...");
  antMessages.put(AntStatus.DONE,         "Build complete.");
  antMessages.put(AntStatus.ERROR,        "Error occurred.");

  // Iterate and print messages
  for (AntStatus status : AntStatus.values() ) {
    out.println("For status " + status + ", message is: " +
                antMessages.get(status));
  }
}

Tiger 把枚举当作类，这可以从 AntStatus 的 Class 对象那里得到证明，该对象不仅可用，而且正被实际使用。归根到底, Tiger 还是把枚举看成是特殊的类类型。