/*
 * Copyright 2011 LMAX Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.lmax.disruptor;

import static java.util.concurrent.TimeUnit.MILLISECONDS;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * Blocking strategy that uses a lock and condition variable for {@link EventProcessor}s waiting on a barrier.
 *
 * This strategy can be used when throughput and low-latency are not as important as CPU resource.
 */
public final class BlockingWaitStrategy implements WaitStrategy
{
    private final Lock lock = new ReentrantLock();
    private final Condition processorNotifyCondition = lock.newCondition();
    private volatile int numWaiters = 0;

    @Override
    public long waitFor(final long sequence, Sequence cursorSequence, final Sequence dependentSequence, final SequenceBarrier barrier)
        throws AlertException, InterruptedException
    {
        long availableSequence;
        if ((availableSequence = cursorSequence.get()) < sequence)
        {
            lock.lock();
            try
            {
                ++numWaiters;
                while ((availableSequence = cursorSequence.get()) < sequence)
                {
                    barrier.checkAlert();
                    processorNotifyCondition.await(1, MILLISECONDS);
                }
            }
            finally
            {
                --numWaiters;
                lock.unlock();
            }
        }

        while ((availableSequence = dependentSequence.get()) < sequence)
        {
            barrier.checkAlert();
        }

        return availableSequence;
    }

    @Override
    public void signalAllWhenBlocking()
    {
        if (0 != numWaiters)
        {
            lock.lock();
            try
            {
                processorNotifyCondition.signalAll();
            }
            finally
            {
                lock.unlock();
            }
        }
    }
}

@@ -1222,49 +1222,8 @@
 n();
-%0A    private volatile int numWaiters = 0;
 %0A%0A  
@@ -1595,38 +1595,8 @@
   %7B%0A
-                ++numWaiters;%0A
     
@@ -1868,38 +1868,8 @@
   %7B%0A
-                --numWaiters;%0A
     
@@ -2153,51 +2153,8 @@
   %7B%0A
-        if (0 != numWaiters)%0A        %7B%0A    
     
@@ -2170,36 +2170,32 @@
 lock();%0A        
-    
 try%0A            
@@ -2186,34 +2186,26 @@
 try%0A        
-  
-  %7B%0A    
+%7B%0A
             
@@ -2246,34 +2246,26 @@
 ();%0A        
-    %7D%0A    
+%7D%0A
         fina
@@ -2272,34 +2272,26 @@
 lly%0A        
- 
-   %7B%0A    
+%7B%0A
             
@@ -2301,38 +2301,24 @@
 k.unlock();%0A
-            %7D%0A
         %7D%0A  

Remove optimisation from BlockingWaitStrategy, has some possible failure conditions