package org.apache.jcs.auxiliary.remote;
   
   /*
    * 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.IOException;
  import java.io.Serializable;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Set;
  import java.util.concurrent.Callable;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.Future;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.TimeoutException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.jcs.auxiliary.AbstractAuxiliaryCacheEventLogging;
  import org.apache.jcs.auxiliary.AuxiliaryCacheAttributes;
  import org.apache.jcs.auxiliary.remote.behavior.IRemoteCacheAttributes;
  import org.apache.jcs.auxiliary.remote.behavior.IRemoteCacheClient;
  import org.apache.jcs.auxiliary.remote.behavior.IRemoteCacheListener;
  import org.apache.jcs.auxiliary.remote.behavior.IRemoteCacheService;
  import org.apache.jcs.engine.CacheConstants;
  import org.apache.jcs.engine.behavior.ICacheElement;
  import org.apache.jcs.engine.behavior.ICacheElementSerialized;
  import org.apache.jcs.engine.behavior.IZombie;
  import org.apache.jcs.engine.logging.behavior.ICacheEventLogger;
  import org.apache.jcs.engine.stats.StatElement;
  import org.apache.jcs.engine.stats.Stats;
  import org.apache.jcs.engine.stats.behavior.IStatElement;
  import org.apache.jcs.engine.stats.behavior.IStats;
  import org.apache.jcs.utils.serialization.SerializationConversionUtil;
  import org.apache.jcs.utils.threadpool.ThreadPoolManager;
  
  /** Abstract base for remote caches. I'm trying to break out and reuse common functionality. */
  public abstract class AbstractRemoteAuxiliaryCache
      extends AbstractAuxiliaryCacheEventLogging
      implements IRemoteCacheClient
  {
      /** Don't change. */
      private static final long serialVersionUID = -5329231850422826461L;
  
      /** The logger. */
      private final static Log log = LogFactory.getLog( AbstractRemoteAuxiliaryCache.class );
  
      /**
       * This does the work. In an RMI instances, it will be a remote reference. In an http remote
       * cache it will be an http client. In zombie mode it is replaced with a balking facade.
       */
      private IRemoteCacheService remoteCacheService;
  
      /** The cacheName */
      protected final String cacheName;
  
      /** The listener. This can be null. */
      private IRemoteCacheListener remoteCacheListener;
  
      /** The configuration values. TODO, we'll need a base here. */
      private IRemoteCacheAttributes remoteCacheAttributes;
  
      /** A thread pool for gets if configured. */
      private ThreadPoolExecutor pool = null;
  
      /** Should we get asynchronously using a pool. */
      private boolean usePoolForGet = false;
  
      /**
       * Creates the base.
       * <p>
       * @param cattr
       * @param remote
       * @param listener
       */
      public AbstractRemoteAuxiliaryCache( IRemoteCacheAttributes cattr, IRemoteCacheService remote,
                                           IRemoteCacheListener listener )
      {
          this.setRemoteCacheAttributes( cattr );
          this.cacheName = cattr.getCacheName();
          this.setRemoteCacheService( remote );
         this.setRemoteCacheListener( listener );
 
         if ( log.isDebugEnabled() )
         {
             log.debug( "Construct> cacheName=" + cattr.getCacheName() );
             log.debug( "irca = " + getRemoteCacheAttributes() );
             log.debug( "remote = " + remote );
             log.debug( "listener = " + listener );
         }
 
         // use a pool if it is greater than 0
         if ( log.isDebugEnabled() )
         {
             log.debug( "GetTimeoutMillis() = " + getRemoteCacheAttributes().getGetTimeoutMillis() );
         }
 
         if ( getRemoteCacheAttributes().getGetTimeoutMillis() > 0 )
         {
             pool = ThreadPoolManager.getInstance().getPool( getRemoteCacheAttributes().getThreadPoolName() );
             if ( log.isDebugEnabled() )
             {
                 log.debug( "Thread Pool = " + pool );
             }
             if ( pool != null )
             {
                 usePoolForGet = true;
             }
         }
     }
 
     /**
      * Synchronously dispose the remote cache; if failed, replace the remote handle with a zombie.
      * <p>
      * @throws IOException
      */
     @Override
     protected void processDispose()
         throws IOException
     {
         if ( log.isInfoEnabled() )
         {
             log.info( "Disposing of remote cache." );
         }
         try
         {
             if ( getRemoteCacheListener() != null )
             {
                 getRemoteCacheListener().dispose();
             }
         }
         catch ( Exception ex )
         {
             log.error( "Couldn't dispose", ex );
             handleException( ex, "Failed to dispose [" + cacheName + "]", ICacheEventLogger.DISPOSE_EVENT );
         }
     }
 
     /**
      * Synchronously get from the remote cache; if failed, replace the remote handle with a zombie.
      * <p>
      * Use threadpool to timeout if a value is set for GetTimeoutMillis
      * <p>
      * If we are a cluster client, we need to leave the Element in its serialized form. Cluster
      * clients cannot deserialize objects. Cluster clients get ICacheElementSerialized objects from
      * other remote servers.
      * <p>
      * @param key
      * @return ICacheElement, a wrapper around the key, value, and attributes
      * @throws IOException
      */
     @Override
     protected ICacheElement processGet( Serializable key )
         throws IOException
     {
         ICacheElement retVal = null;
         try
         {
             if ( usePoolForGet )
             {
                 retVal = getUsingPool( key );
             }
             else
             {
                 retVal = getRemoteCacheService().get( cacheName, key, getListenerId() );
             }
 
             // Eventually the instance of will not be necessary.
             if ( retVal != null && retVal instanceof ICacheElementSerialized )
             {
                 // Never try to deserialize if you are a cluster client. Cluster
                 // clients are merely intra-remote cache communicators. Remote caches are assumed
                 // to have no ability to deserialze the objects.
                 if ( this.getRemoteCacheAttributes().getRemoteType() != IRemoteCacheAttributes.CLUSTER )
                 {
                     retVal = SerializationConversionUtil.getDeSerializedCacheElement( (ICacheElementSerialized) retVal,
                                                                                       this.elementSerializer );
                 }
             }
         }
         catch ( Exception ex )
         {
             handleException( ex, "Failed to get [" + key + "] from [" + cacheName + "]", ICacheEventLogger.GET_EVENT );
         }
         return retVal;
     }
 
     /**
      * This allows gets to timeout in case of remote server machine shutdown.
      * <p>
      * @param key
      * @return ICacheElement
      * @throws IOException
      */
     public ICacheElement getUsingPool( final Serializable key )
         throws IOException
     {
         int timeout = getRemoteCacheAttributes().getGetTimeoutMillis();
 
         try
         {
             Callable<ICacheElement> command = new Callable<ICacheElement>()
             {
                 public ICacheElement call()
                     throws IOException
                 {
                     return getRemoteCacheService().get( cacheName, key, getListenerId() );
                 }
             };
 
             // execute using the pool
             Future<ICacheElement> future = pool.submit(command);
 
             // used timed get in order to timeout
             ICacheElement ice = future.get(timeout, TimeUnit.MILLISECONDS);
 
             if ( log.isDebugEnabled() )
             {
                 if ( ice == null )
                 {
                     log.debug( "nothing found in remote cache" );
                 }
                 else
                 {
                     log.debug( "found item in remote cache" );
                 }
             }
             return ice;
         }
         catch ( TimeoutException te )
         {
             log.warn( "TimeoutException, Get Request timed out after " + timeout );
             throw new IOException( "Get Request timed out after " + timeout );
         }
         catch ( InterruptedException ex )
         {
             log.warn( "InterruptedException, Get Request timed out after " + timeout );
             throw new IOException( "Get Request timed out after " + timeout );
         }
         catch (ExecutionException ex)
         {
             // assume that this is an IOException thrown by the callable.
             log.error( "ExecutionException, Assuming an IO exception thrown in the background.", ex );
             throw new IOException( "Get Request timed out after " + timeout );
         }
     }
 
     /**
      * Calls get matching on the server. Each entry in the result is unwrapped.
      * <p>
      * @param pattern
      * @return Map
      * @throws IOException
      */
     @Override
     public Map<Serializable, ICacheElement> processGetMatching( String pattern )
         throws IOException
     {
         Map<Serializable, ICacheElement> results = new HashMap<Serializable, ICacheElement>();
         try
         {
             Map<Serializable, ICacheElement> rawResults = getRemoteCacheService().getMatching( cacheName, pattern, getListenerId() );
 
             // Eventually the instance of will not be necessary.
             if ( rawResults != null )
             {
                 for (Map.Entry<Serializable, ICacheElement> entry : rawResults.entrySet())
                 {
                     ICacheElement unwrappedResult = null;
                     if ( entry.getValue() instanceof ICacheElementSerialized )
                     {
                         // Never try to deserialize if you are a cluster client. Cluster
                         // clients are merely intra-remote cache communicators. Remote caches are assumed
                         // to have no ability to deserialize the objects.
                         if ( this.getRemoteCacheAttributes().getRemoteType() != IRemoteCacheAttributes.CLUSTER )
                         {
                             unwrappedResult = SerializationConversionUtil
                                 .getDeSerializedCacheElement( (ICacheElementSerialized) entry.getValue(),
                                                               this.elementSerializer );
                         }
                     }
                     else
                     {
                         unwrappedResult = entry.getValue();
                     }
                     results.put( entry.getKey(), unwrappedResult );
                 }
             }
         }
         catch ( Exception ex )
         {
             handleException( ex, "Failed to getMatching [" + pattern + "] from [" + cacheName + "]",
                              ICacheEventLogger.GET_EVENT );
         }
         return results;
     }
 
     /**
      * Gets multiple items from the cache based on the given set of keys.
      * <p>
      * @param keys
      * @return a map of Serializable key to ICacheElement element, or an empty map if there is no
      *         data in cache for any of these keys
      * @throws IOException
      */
     @Override
     protected Map<Serializable, ICacheElement> processGetMultiple( Set<Serializable> keys )
         throws IOException
     {
         Map<Serializable, ICacheElement> elements = new HashMap<Serializable, ICacheElement>();
         if ( keys != null && !keys.isEmpty() )
         {
             for (Serializable key : keys)
             {
                 ICacheElement element = get( key );
 
                 if ( element != null )
                 {
                     elements.put( key, element );
                 }
             }
         }
         return elements;
     }
 
     /**
      * Synchronously remove from the remote cache; if failed, replace the remote handle with a
      * zombie.
      * <p>
      * @param key
      * @return boolean, whether or not the item was removed
      * @throws IOException
      */
     @Override
     protected boolean processRemove( Serializable key )
         throws IOException
     {
         if ( !this.getRemoteCacheAttributes().getGetOnly() )
         {
             if ( log.isDebugEnabled() )
             {
                 log.debug( "remove> key=" + key );
             }
             try
             {
                 getRemoteCacheService().remove( cacheName, key, getListenerId() );
             }
             catch ( Exception ex )
             {
                 handleException( ex, "Failed to remove " + key + " from " + cacheName, ICacheEventLogger.REMOVE_EVENT );
             }
             return true;
         }
         return false;
     }
 
     /**
      * Synchronously removeAll from the remote cache; if failed, replace the remote handle with a
      * zombie.
      * <p>
      * @throws IOException
      */
     @Override
     protected void processRemoveAll()
         throws IOException
     {
         if ( !this.getRemoteCacheAttributes().getGetOnly() )
         {
             try
             {
                 getRemoteCacheService().removeAll( cacheName, getListenerId() );
             }
             catch ( Exception ex )
             {
                 handleException( ex, "Failed to remove all from " + cacheName, ICacheEventLogger.REMOVEALL_EVENT );
             }
         }
     }
 
     /**
      * Serializes the object and then calls update on the remote server with the byte array. The
      * byte array is wrapped in a ICacheElementSerialized. This allows the remote server to operate
      * without any knowledge of caches classes.
      * <p>
      * @param ce
      * @throws IOException
      */
     @Override
     protected void processUpdate( ICacheElement ce )
         throws IOException
     {
         if ( !getRemoteCacheAttributes().getGetOnly() )
         {
             ICacheElementSerialized serialized = null;
             try
             {
                 if ( log.isDebugEnabled() )
                 {
                     log.debug( "sending item to remote server" );
                 }
 
                 // convert so we don't have to know about the object on the
                 // other end.
                 serialized = SerializationConversionUtil.getSerializedCacheElement( ce, this.elementSerializer );
 
                 remoteCacheService.update( serialized, getListenerId() );
             }
             catch ( NullPointerException npe )
             {
                 log.error( "npe for ce = " + ce + "ce.attr = " + ce.getElementAttributes(), npe );
             }
             catch ( Exception ex )
             {
                 // event queue will wait and retry
                 handleException( ex, "Failed to put [" + ce.getKey() + "] to " + ce.getCacheName(),
                                  ICacheEventLogger.UPDATE_EVENT );
             }
         }
         else
         {
             if ( log.isDebugEnabled() )
             {
                 log.debug( "get only mode, not sending to remote server" );
             }
         }
     }
 
     /**
      * Returns all the keys for a group.
      * <p>
      * @param groupName
      * @return Set
      * @throws java.rmi.RemoteException
      * @throws IOException
      */
     public Set<Serializable> getGroupKeys( String groupName )
         throws java.rmi.RemoteException, IOException
     {
         return getRemoteCacheService().getGroupKeys( cacheName, groupName );
     }
 
     /**
      * Allows other member of this package to access the listener. This is mainly needed for
      * deregistering a listener.
      * <p>
      * @return IRemoteCacheListener, the listener for this remote server
      */
     public IRemoteCacheListener getListener()
     {
         return getRemoteCacheListener();
     }
 
     /**
      * let the remote cache set a listener_id. Since there is only one listener for all the regions
      * and every region gets registered? the id shouldn't be set if it isn't zero. If it is we
      * assume that it is a reconnect.
      * <p>
      * @param id The new listenerId value
      */
     public void setListenerId( long id )
     {
         if ( getRemoteCacheListener() != null )
         {
             try
             {
                 getRemoteCacheListener().setListenerId( id );
 
                 if ( log.isDebugEnabled() )
                 {
                     log.debug( "set listenerId = " + id );
                 }
             }
             catch ( Exception e )
             {
                 log.error( "Problem setting listenerId", e );
             }
         }
     }
 
     /**
      * Gets the listenerId attribute of the RemoteCacheListener object
      * <p>
      * @return The listenerId value
      */
     public long getListenerId()
     {
         if ( getRemoteCacheListener() != null )
         {
             try
             {
                 if ( log.isDebugEnabled() )
                 {
                     log.debug( "get listenerId = " + getRemoteCacheListener().getListenerId() );
                 }
                 return getRemoteCacheListener().getListenerId();
             }
             catch ( Exception e )
             {
                 log.error( "Problem getting listenerId", e );
             }
         }
         return -1;
     }
 
     /**
      * Returns the current cache size.
      * @return The size value
      */
     public int getSize()
     {
         return 0;
     }
 
     /**
      * Custom exception handling some children.  This should be used to initiate failover.
      * <p>
      * @param ex
      * @param msg
      * @param eventName
      * @throws IOException
      */
     protected abstract void handleException( Exception ex, String msg, String eventName )
         throws IOException;
 
     /**
      * Gets the stats attribute of the RemoteCache object.
      * <p>
      * @return The stats value
      */
     public String getStats()
     {
         return getStatistics().toString();
     }
 
     /**
      * @return IStats object
      */
     public IStats getStatistics()
     {
         IStats stats = new Stats();
         stats.setTypeName( "AbstractRemoteAuxiliaryCache" );
 
         ArrayList<IStatElement> elems = new ArrayList<IStatElement>();
 
         IStatElement se = null;
 
         se = new StatElement();
         se.setName( "Remote Type" );
         se.setData( this.getRemoteCacheAttributes().getRemoteTypeName() + "" );
         elems.add( se );
 
         if ( this.getRemoteCacheAttributes().getRemoteType() == IRemoteCacheAttributes.CLUSTER )
         {
             // something cluster specific
         }
 
         // no data gathered here
 
         se = new StatElement();
         se.setName( "UsePoolForGet" );
         se.setData( "" + usePoolForGet );
         elems.add( se );
 
         if ( pool != null )
         {
             se = new StatElement();
             se.setName( "Pool Size" );
             se.setData( "" + pool.getPoolSize() );
             elems.add( se );
 
             se = new StatElement();
             se.setName( "Maximum Pool Size" );
             se.setData( "" + pool.getMaximumPoolSize() );
             elems.add( se );
         }
 
         if ( getRemoteCacheService() instanceof ZombieRemoteCacheService )
         {
             se = new StatElement();
             se.setName( "Zombie Queue Size" );
             se.setData( "" + ( (ZombieRemoteCacheService) getRemoteCacheService() ).getQueueSize() );
             elems.add( se );
         }
 
         // get an array and put them in the Stats object
         IStatElement[] ses = elems.toArray( new StatElement[0] );
         stats.setStatElements( ses );
 
         return stats;
     }
 
     /**
      * Returns the cache status. An error status indicates the remote connection is not available.
      * <p>
      * @return The status value
      */
     public int getStatus()
     {
         return getRemoteCacheService() instanceof IZombie ? CacheConstants.STATUS_ERROR : CacheConstants.STATUS_ALIVE;
     }
 
     /**
      * Replaces the current remote cache service handle with the given handle. If the current remote
      * is a Zombie, then it propagates any events that are queued to the restored service.
      * <p>
      * @param restoredRemote IRemoteCacheService -- the remote server or proxy to the remote server
      */
     public void fixCache( IRemoteCacheService restoredRemote )
     {
         if ( getRemoteCacheService() != null && getRemoteCacheService() instanceof ZombieRemoteCacheService )
         {
             ZombieRemoteCacheService zombie = (ZombieRemoteCacheService) getRemoteCacheService();
             setRemoteCacheService( restoredRemote );
             try
             {
                 zombie.propagateEvents( restoredRemote );
             }
             catch ( Exception e )
             {
                 try
                 {
                     handleException( e, "Problem propagating events from Zombie Queue to new Remote Service.",
                                      "fixCache" );
                 }
                 catch ( IOException e1 )
                 {
                     // swallow, since this is just expected kick back.  Handle always throws
                 }
             }
         }
         else
         {
             setRemoteCacheService( restoredRemote );
         }
     }
 
 
     /**
      * Gets the cacheType attribute of the RemoteCache object
      * @return The cacheType value
      */
     public int getCacheType()
     {
         return REMOTE_CACHE;
     }
 
     /**
      * Gets the cacheName attribute of the RemoteCache object.
      * <p>
      * @return The cacheName value
      */
     public String getCacheName()
     {
         return cacheName;
     }
 
     /**
      * @param remote the remote to set
      */
     protected void setRemoteCacheService( IRemoteCacheService remote )
     {
         this.remoteCacheService = remote;
     }
 
     /**
      * @return the remote
      */
     protected IRemoteCacheService getRemoteCacheService()
     {
         return remoteCacheService;
     }
 
     /**
      * @return Returns the AuxiliaryCacheAttributes.
      */
     public AuxiliaryCacheAttributes getAuxiliaryCacheAttributes()
     {
         return getRemoteCacheAttributes();
     }
 
     /**
      * @param remoteCacheAttributes the remoteCacheAttributes to set
      */
     protected void setRemoteCacheAttributes( IRemoteCacheAttributes remoteCacheAttributes )
     {
         this.remoteCacheAttributes = remoteCacheAttributes;
     }
 
     /**
      * @return the remoteCacheAttributes
      */
     protected IRemoteCacheAttributes getRemoteCacheAttributes()
     {
         return remoteCacheAttributes;
     }
 
     /**
      * @param remoteCacheListener the remoteCacheListener to set
      */
     protected void setRemoteCacheListener( IRemoteCacheListener remoteCacheListener )
     {
         this.remoteCacheListener = remoteCacheListener;
     }
 
     /**
      * @return the remoteCacheListener
      */
     protected IRemoteCacheListener getRemoteCacheListener()
     {
         return remoteCacheListener;
     }
 }