// This example is from the book _Java Threads_ by Scott Oaks and Henry Wong. 
// Written by Scott Oaks and Henry Wong.
// Copyright (c) 1997 O'Reilly & Associates.
// You may study, use, modify, and distribute this example for any purpose.
// This example is provided WITHOUT WARRANTY either expressed or implied.

// Sample ResourceThrottle -- Chapter 4, p. 79.

public class ResourceThrottle {
     private int resourcecount = 0;
     private int resourcemax = 1;

     public ResourceThrottle (int max) {
          resourcecount = 0;
          resourcemax = max;
     }

     public synchronized void getResource (int numberof) {
          while (true) {
               if ((resourcecount + numberof) <= resourcemax) {
                    resourcecount += numberof;
                    break;
               }
               try {
                    wait();
               } catch (Exception e) {}
          }
     }

     public synchronized void freeResource (int numberof) {
               resourcecount -= numberof;
               notifyAll();
     }
}