/*
    * 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.river.outrigger.snaplogstore;
  
  import org.apache.river.config.Config;
  import org.apache.river.outrigger.LogOps;
  import org.apache.river.outrigger.Recover;
  import org.apache.river.outrigger.OutriggerServerImpl;
  import org.apache.river.outrigger.Store;
  import org.apache.river.system.FileSystem;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import net.jini.config.Configuration;
  import net.jini.config.ConfigurationException;
  import net.jini.space.InternalSpaceException;
  
  /**
   * @author Sun Microsystems, Inc.
   *
   * @see org.apache.river.outrigger.OutriggerServerImpl
   */
  public class LogStore implements Store {
      private volatile LogOutputFile	log;
      private final String	path;
      private final BackEnd		be;
      private final int			maxOps;
  
      /** Logger for logging persistent store related information */
      private static final Logger logger = 
  	Logger.getLogger(OutriggerServerImpl.storeLoggerName);
  
      /**
       * Create a new <code>LogStore</code>.
       * @param config the directory to use for persistence.
       * @throws ConfigurationException if there's a problem with the configuration.
       */
      public LogStore(Configuration config) throws ConfigurationException {
  	path = (String)Config.getNonNullEntry(config,
  				OutriggerServerImpl.COMPONENT_NAME,
  				OutriggerServerImpl.PERSISTENCE_DIR_CONFIG_ENTRY,
  				String.class);
  
  	logger.log(Level.CONFIG, "using directory {0}", path);
  
  	FileSystem.ensureDir(path);
  
  	be = new BackEnd(path);
  
  	maxOps = Config.getIntEntry(config, 
  				OutriggerServerImpl.COMPONENT_NAME,
  				"maxOps",
  				1000, 1, Integer.MAX_VALUE);
      }
  
      /**
       * Setup store, recover previous state if any.
       *
       * @param space object used for recovery of previous state
       *
       * @return object used to persist state
       */
      public LogOps setupStore(Recover space) {
  	try {
  	    be.setupStore(space);
  
  	    // Use the log type as the file prefix
  	    //
  	    log = new LogOutputFile(
  		new File(path, LogFile.LOG_TYPE).getAbsolutePath(),
  		maxOps);
  
  	    log.observable().addObserver(be);
  	} catch (IOException e) {
  	    final String msg = "LogStore: log creation failed";
  	    final InternalSpaceException ise = 
  		new InternalSpaceException(msg, e);
  	    logger.log(Level.SEVERE, msg, ise);
  	    throw ise;
  	}
  	return log;
     }
 
     /**
      * Destroy everything.
      */
     public void destroy() throws IOException {
 	be.destroy();
 	log.destroy();
 	new File(path).delete();
     }
 
     // Inherit from super
     public void close() throws IOException {
 	be.close();
 	log.close();
     }
 }