Reentrant Locks - Synchronization on multiple Conditions

After looking at a way you can do a waited lock on a synchronised monitor in java, it needs a much more object oriented way of handling multiple scenarios.

The sychronised-wait-notify paradigm works if you wait and notify on the monitor based on one condition (wait before borrow if not available). The Give back doesnot wait ever, It just gives back. The pool kills any over flow. What if you need to put a conditional wait on that too? something like (give back only if object pool is not full and WAIT until space is available)

Here is where you have Java 5's Lock - Conditions paradim comes handy. A lock is objectification of the monitor, Threads that need to be synchronised on one monitor is can go through Locks instead. However, Locks are more useful if you have multiple conditions on which you what these threads to wait and be notified.

Take the above scenario, which is the case of a Bounded buffer where there are two conditions on which threads need to wait, empty and full. If buffer is empty, a get() need to wait until something comes up; And if it is full, a put() needs to wait until there is space. However since buffer is the same object they lock on to using synchronised will block both producers and consumers in the same wait set; So to make them wait in seperate queues, Lock and Conditions shall be used.

Look at an example in Conditions javadoc:

 class BoundedBuffer {
   final Lock lock = new ReentrantLock();
   final Condition notFull  = lock.newCondition(); 
   final Condition notEmpty = lock.newCondition(); 

   public void put(Object x) throws InterruptedException {
     lock.lock();
     try {
       while (this.isNotFull()) 
         notFull.await();
 //Do some logic to put object in buffer
       notEmpty.signal();
     } finally {
       lock.unlock();
     }
   }

   public Object take() throws InterruptedException {
     lock.lock(); //Same lock
     try {
       while (count == 0) 
         notEmpty.await();//Different Condition
 //Do some logic to put object in buffer
       notFull.signal();
       return x;
     } finally {
       lock.unlock();
     }
   } 
 }

Please bear in mind that use of Locks is comtemplated by some experts. However, I dont see anyother way this could be implemented atleast if not cleanly