/*
    * 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.
   */
  package org.apache.commons.jcs.jcache.extras.writer;
  
  import javax.cache.Cache;
  import javax.cache.configuration.Factory;
  import javax.cache.integration.CacheWriter;
  import javax.cache.integration.CacheWriterException;
  import java.io.Closeable;
  import java.io.IOException;
  import java.util.Collection;
  import java.util.List;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.ThreadFactory;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  public class AsyncCacheWriter<K, V> implements CacheWriter<K, V>, Closeable, Factory<CacheWriter<K, V>>
  {
      private static final Logger LOGGER = Logger.getLogger(AsyncCacheWriter.class.getName());
  
      private final CacheWriter<K, V> writer;
      private final ExecutorService pool;
  
      public AsyncCacheWriter(final CacheWriter<K, V> delegate, final int poolSize)
      {
          writer = delegate;
          pool = Executors.newFixedThreadPool(
                  poolSize, new DaemonThreadFactory(delegate.getClass().getName() + "-" + delegate.hashCode() + "-"));
      }
  
      @Override
      public void write(final Cache.Entry<? extends K, ? extends V> entry) throws CacheWriterException
      {
          pool.submit(new ExceptionProtectionRunnable()
          {
              @Override
              public void doRun()
              {
                  writer.write(entry);
              }
          });
      }
  
      @Override
      public void writeAll(final Collection<Cache.Entry<? extends K, ? extends V>> entries) throws CacheWriterException
      {
          pool.submit(new ExceptionProtectionRunnable()
          {
              @Override
              public void doRun()
              {
                  writer.writeAll(entries);
              }
          });
      }
  
      @Override
      public void delete(final Object key) throws CacheWriterException
      {
          pool.submit(new ExceptionProtectionRunnable()
          {
              @Override
              public void doRun()
              {
                  writer.delete(key);
              }
          });
      }
  
      @Override
      public void deleteAll(final Collection<?> keys) throws CacheWriterException
      {
          pool.submit(new ExceptionProtectionRunnable()
          {
              @Override
              public void doRun()
              {
                  writer.deleteAll(keys);
              }
          });
     }
 
     @Override
     public void close() throws IOException
     {
         final List<Runnable> runnables = pool.shutdownNow();
         for (final Runnable r : runnables)
         {
             r.run();
         }
     }
 
     @Override
     public CacheWriter<K, V> create()
     {
         return this;
     }
 
     // avoid dep on impl
     private static class DaemonThreadFactory implements ThreadFactory
     {
         private final AtomicInteger index = new AtomicInteger(1);
         private final String prefix;
 
         public DaemonThreadFactory(final String prefix)
         {
             this.prefix = prefix;
         }
 
         @Override
         public Thread newThread( final Runnable runner )
         {
             final Thread t = new Thread( runner );
             t.setName(prefix + index.getAndIncrement());
             t.setDaemon(true);
             return t;
         }
     }
 
     private static abstract class ExceptionProtectionRunnable implements Runnable
     {
         @Override
         public void run()
         {
             try
             {
                 doRun();
             }
             catch (final Exception e)
             {
                 LOGGER.log(Level.SEVERE, e.getMessage(), e);
             }
         }
 
         protected abstract void doRun();
     }
 }