独家访问方法/字段

Question

In my application I have a class which has a variable which gets updated everytime a new event comes in:

class Logger{

  private String mVariable ="";

  public void onEvent(Event e) {
    //update mVariable here
  }

  public void log() {
     //write mVariable to file
  }
}

Now, I have another class which wants to trigger the Logger class to write the current value to a file.

class Trigger{

   //this is another event, not the event for which Logger is waiting for
   public void onEvent(Event e) {
      mLogger.log();
   }
}

How can I ensure that the Trigger class has exclusive access to the value of mVariable whenever it wants? ie When the Trigger class calls the log method the value of mVariable should not be overridden by the Logger class of course.

Answer 1

使两个方法synchronized然后调用lock（）将锁定对onEvent（）的访问