package org.apache.commons.jcs3;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   */
  
  import java.util.List;
  import java.util.concurrent.CopyOnWriteArrayList;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.apache.commons.jcs3.access.GroupCacheAccess;
  import org.apache.commons.jcs3.access.exception.CacheException;
  
  import junit.framework.TestCase;
  
  /**
   * Test Case for JCS-73, modeled after the Groovy code by Alexander Kleymenov
   */
  public class JCSConcurrentCacheAccessUnitTest extends TestCase
  {
      private final static int THREADS = 20;
      private final static int LOOPS = 10000;
  
      /**
       * the cache instance
       */
      protected GroupCacheAccess<Integer, String> cache;
  
      /**
       * the group name
       */
      protected String group = "group";
  
      /**
       * the error count
       */
      protected AtomicInteger errcount;
  
      /**
       * Collect all value mismatches
       */
      protected List<String> valueMismatchList;
  
      @Override
  	protected void setUp() throws Exception
  	{
          super.setUp();
          JCS.setConfigFilename( "/TestJCS-73.ccf" );
          cache = JCS.getGroupCacheInstance( "cache" );
          errcount = new AtomicInteger(0);
          valueMismatchList = new CopyOnWriteArrayList<>();
  	}
  
      @Override
      protected void tearDown()
          throws Exception
      {
          super.tearDown();
          cache.clear();
          cache.dispose();
      }
  
      /**
       * Worker thread
       */
      protected class Worker extends Thread
      {
      	@Override
  		public void run()
  		{
  			final String name = getName();
  
  			for (int idx = 0; idx < LOOPS; idx++)
  			{
  				if (idx > 0)
  				{
  					// get previously stored value
  		            String res = cache.getFromGroup(Integer.valueOf(idx-1), group);
  
  		            if (res == null)
  		            {
  		                // null value got inspite of the fact it was placed in cache!
  		                System.out.println("ERROR: for " + idx + " in " + name);
  		                errcount.incrementAndGet();
 
 		                // try to get the value again:
 		                int n = 5;
 		                while (n-- > 0)
 		                {
 		                    res = cache.getFromGroup(Integer.valueOf(idx-1), group);
 		                    if (res != null)
 		                    {
 		                        // the value finally appeared in cache
 		                    	System.out.println("ERROR FIXED for " + idx + ": " + res + " " + name);
 		                    	errcount.decrementAndGet();
 		                        break;
 		                    }
 
 		                    System.out.println("ERROR STILL PERSISTS for " + idx + " in " + name);
 		                    try
 		                    {
 								Thread.sleep(1000);
 							}
 		                    catch (final InterruptedException e)
 							{
 								// continue
 							}
 		                }
 		            }
 
 		            if (!String.valueOf(idx-1).equals(res))
 		            {
 		                valueMismatchList.add(String.format("Values do not match: %s - %s", String.valueOf(idx-1), res));
 		            }
 				}
 
 				 // put value in the cache
 		        try
 		        {
 					cache.putInGroup(Integer.valueOf(idx), group, String.valueOf(idx));
 				}
 		        catch (final CacheException e)
 		        {
 		        	// continue
 				}
 
 //		        if ((idx % 1000) == 0)
 //		        {
 //		        	System.out.println(name + " " + idx);
 //		        }
 			}
 
 		}
     }
 
 	/**
      *
      * @throws Exception
      */
     public void testConcurrentAccess()
         throws Exception
     {
     	final Worker[] worker = new Worker[THREADS];
 
         for (int i = 0; i < THREADS; i++)
         {
         	worker[i] = new Worker();
         	worker[i].start();
         }
 
         for (int i = 0; i < THREADS; i++)
         {
         	worker[i].join();
         }
 
         assertEquals("Error count should be 0",  0, errcount.intValue());
         for (final String msg : valueMismatchList)
         {
             System.out.println(msg);
         }
         assertEquals("Value mismatch count should be 0",  0, valueMismatchList.size());
     }
 
 }