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.io.Serializable;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.commons.jcs3.access.CacheAccess;
  import org.apache.commons.jcs3.engine.stats.behavior.IStatElement;
  import org.apache.commons.jcs3.engine.stats.behavior.IStats;
  import org.apache.commons.jcs3.log.Log;
  import org.apache.commons.jcs3.log.LogManager;
  
  import junit.framework.TestCase;
  
  /**
   * This is based on a test that was posted to the user's list:
   * <p>
   * http://www.opensubscriber.com/message/jcs-users@jakarta.apache.org/2435965.html
   */
  public class JCSThrashTest
      extends TestCase
  {
      /** The logger. */
      private static final Log LOG = LogManager.getLog( JCSThrashTest.class.getName() );
  
      /**
       * the cache instance
       */
      protected CacheAccess<String, Serializable> jcs;
  
      /**
       * Sets up the test
       * @throws Exception
       */
      @Override
      protected void setUp()
          throws Exception
      {
          super.setUp();
          JCS.setConfigFilename( "/TestThrash.ccf" );
          jcs = JCS.getInstance( "testcache" );
      }
  
      /**
       * @throws Exception
       */
      @Override
      protected void tearDown()
          throws Exception
      {
          super.tearDown();
          jcs.clear();
          jcs.dispose();
      }
  
      /**
       * Tests adding an entry.
       * @throws Exception
       */
      public void testPut()
          throws Exception
      {
          final String value = "value";
          final String key = "key";
  
          // Make sure the element is not found
          assertEquals( 0, getListSize() );
  
          assertNull( jcs.get( key ) );
  
          jcs.put( key, value );
  
          // Get the element
          LOG.info( "jcs.getStats(): " + jcs.getStatistics() );
          assertEquals( 1, getListSize() );
          assertNotNull( jcs.get( key ) );
          assertEquals( value, jcs.get( key ) );
      }
  
      /**
      * Test elements can be removed from the store
      * @throws Exception
      */
     public void testRemove()
         throws Exception
     {
         jcs.put( "key1", "value1" );
         assertEquals( 1, getListSize() );
 
         jcs.remove( "key1" );
         assertEquals( 0, getListSize() );
 
         jcs.put( "key2", "value2" );
         jcs.put( "key3", "value3" );
         assertEquals( 2, getListSize() );
 
         jcs.remove( "key2" );
         assertEquals( 1, getListSize() );
 
         // Try to remove an object that is not there in the store
         jcs.remove( "key4" );
         assertEquals( 1, getListSize() );
     }
 
     /**
      * This does a bunch of work and then verifies that the memory has not grown by much. Most of
      * the time the amount of memory used after the test is less.
      * @throws Exception
      */
     public void testForMemoryLeaks()
         throws Exception
     {
         final long differenceMemoryCache = thrashCache();
         LOG.info( "Memory Difference is: " + differenceMemoryCache );
         assertTrue( differenceMemoryCache < 500000 );
 
         //LOG.info( "Memory Used is: " + measureMemoryUse() );
     }
 
     /**
      * @return time
      * @throws Exception
      */
     protected long thrashCache()
         throws Exception
     {
         final long startingSize = measureMemoryUse();
         LOG.info( "Memory Used is: " + startingSize );
 
         final String value = "value";
         final String key = "key";
 
         // Add the entry
         jcs.put( key, value );
 
         // Create 15 threads that read the keys;
         final List<Executable> executables = new ArrayList<>();
         for ( int i = 0; i < 15; i++ )
         {
             final JCSThrashTest.Executable executable = () ->
             {
                 for ( int j = 0; j < 500; j++ )
                 {
                     final String keyj = "key" + j;
                     jcs.get( keyj );
                 }
                 jcs.get( "key" );
             };
             executables.add( executable );
         }
 
         // Create 15 threads that are insert 500 keys with large byte[] as
         // values
         for ( int i = 0; i < 15; i++ )
         {
             final JCSThrashTest.Executable executable = () ->
             {
 
                 // Add a bunch of entries
                 for ( int j = 0; j < 500; j++ )
                 {
                     // Use a random length value
                     final String keyj = "key" + j;
                     final byte[] valuej = new byte[10000];
                     jcs.put( keyj, valuej );
                 }
             };
             executables.add( executable );
         }
 
         runThreads( executables );
         jcs.clear();
 
         final long finishingSize = measureMemoryUse();
         LOG.info( "Memory Used is: " + finishingSize );
         return finishingSize - startingSize;
     }
 
     /**
      * Runs a set of threads, for a fixed amount of time.
      * <p>
      * @param executables
      * @throws Exception
      */
     protected void runThreads( final List<Executable> executables )
         throws Exception
     {
 
         final long endTime = System.currentTimeMillis() + 10000;
         final Throwable[] errors = new Throwable[1];
 
         // Spin up the threads
         final Thread[] threads = new Thread[executables.size()];
         for ( int i = 0; i < threads.length; i++ )
         {
             final JCSThrashTest.Executable executable = executables.get( i );
             threads[i] = new Thread()
             {
                 @Override
                 public void run()
                 {
                     try
                     {
                         // Run the thread until the given end time
                         while ( System.currentTimeMillis() < endTime )
                         {
                             executable.execute();
                         }
                     }
                     catch ( final Throwable t )
                     {
                         // Hang on to any errors
                         errors[0] = t;
                     }
                 }
             };
             threads[i].start();
         }
 
         // Wait for the threads to finish
         for (final Thread thread : threads) {
             thread.join();
         }
 
         // Throw any error that happened
         if ( errors[0] != null )
         {
             throw new Exception( "Test thread failed.", errors[0] );
         }
     }
 
     /**
      * Measure memory used by the VM.
      * <p>
      * @return bytes
      * @throws InterruptedException
      */
     protected long measureMemoryUse()
         throws InterruptedException
     {
         System.gc();
         Thread.sleep( 3000 );
         System.gc();
         return Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();
     }
 
     /**
      * A runnable, that can throw an exception.
      */
     protected interface Executable
     {
         /**
          * Executes this object.
          * @throws Exception
          */
         void execute()
             throws Exception;
     }
 
     /**
      * @return size
      */
     private int getListSize()
     {
         final String listSize = "List Size";
         final String lruMemoryCache = "LRU Memory Cache";
         String result = "0";
         final List<IStats> istats = jcs.getStatistics().getAuxiliaryCacheStats();
         for ( final IStats istat : istats )
         {
             final List<IStatElement<?>> statElements = istat.getStatElements();
             if ( lruMemoryCache.equals( istat.getTypeName() ) )
             {
                 for ( final IStatElement<?> statElement : statElements )
                 {
                     if ( listSize.equals( statElement.getName() ) )
                     {
                         result = statElement.getData().toString();
                         break;
                     }
                 }
             }
         }
         return Integer.parseInt( result );
     }
 }