chris@3: /*
chris@3:  *   SONEWS News Server
chris@3:  *   see AUTHORS for the list of contributors
chris@3:  *
chris@3:  *   This program is free software: you can redistribute it and/or modify
chris@3:  *   it under the terms of the GNU General Public License as published by
chris@3:  *   the Free Software Foundation, either version 3 of the License, or
chris@3:  *   (at your option) any later version.
chris@3:  *
chris@3:  *   This program is distributed in the hope that it will be useful,
chris@3:  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
chris@3:  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
chris@3:  *   GNU General Public License for more details.
chris@3:  *
chris@3:  *   You should have received a copy of the GNU General Public License
chris@3:  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
chris@3:  */
chris@3: 
chris@3: package org.sonews.daemon;
chris@3: 
chris@3: import java.util.HashMap;
chris@3: import java.util.Map;
chris@3: import java.util.concurrent.ConcurrentHashMap;
chris@3: import org.sonews.daemon.command.Command;
chris@3: import org.sonews.daemon.command.UnsupportedCommand;
chris@3: import org.sonews.util.Log;
chris@3: import org.sonews.util.io.Resource;
chris@3: 
chris@3: /**
chris@3:  * Selects the correct command processing class.
chris@3:  * @author Christian Lins
cli@21:  * @since sonews/1.0
chris@3:  */
cli@21: public class CommandSelector
chris@3: {
chris@3: 
chris@3:   private static Map<Thread, CommandSelector> instances
chris@3:     = new ConcurrentHashMap<Thread, CommandSelector>();
cli@21:   private static Map<String, Class<?>> commandClassesMapping
cli@21:     = new ConcurrentHashMap<String, Class<?>>();
chris@3: 
cli@21:   static
chris@3:   {
chris@3:     String[] classes = Resource.getAsString("helpers/commands.list", true).split("\n");
chris@3:     for(String className : classes)
chris@3:     {
cli@10:       if(className.charAt(0) == '#')
cli@10:       {
cli@10:         // Skip comments
cli@10:         continue;
cli@10:       }
cli@10: 
chris@3:       try
chris@3:       {
cli@21:         addCommandHandler(className);
chris@3:       }
chris@3:       catch(ClassNotFoundException ex)
chris@3:       {
cli@15:         Log.get().warning("Could not load command class: " + ex);
chris@3:       }
chris@3:       catch(InstantiationException ex)
chris@3:       {
cli@15:         Log.get().severe("Could not instantiate command class: " + ex);
chris@3:       }
chris@3:       catch(IllegalAccessException ex)
chris@3:       {
cli@15:         Log.get().severe("Could not access command class: " + ex);
chris@3:       }
chris@3:     }
chris@3:   }
chris@3: 
cli@21:   public static void addCommandHandler(String className)
cli@21:     throws ClassNotFoundException, InstantiationException, IllegalAccessException
cli@21:   {
cli@21:     Class<?> clazz = Class.forName(className);
cli@21:     Command cmd = (Command)clazz.newInstance();
cli@21:     String[] cmdStrs = cmd.getSupportedCommandStrings();
cli@21:     for (String cmdStr : cmdStrs)
cli@21:     {
cli@21:       commandClassesMapping.put(cmdStr, clazz);
cli@21:     }
cli@21:   }
cli@21: 
cli@21:   public static CommandSelector getInstance()
cli@21:   {
cli@21:     CommandSelector csel = instances.get(Thread.currentThread());
cli@21:     if(csel == null)
cli@21:     {
cli@21:       csel = new CommandSelector();
cli@21:       instances.put(Thread.currentThread(), csel);
cli@21:     }
cli@21:     return csel;
cli@21:   }
cli@21: 
cli@21:   private Map<String, Command> commandMapping = new HashMap<String, Command>();
cli@21:   private Command              unsupportedCmd = new UnsupportedCommand();
cli@21: 
cli@21:   private CommandSelector()
cli@21:   {}
cli@21: 
chris@3:   public Command get(String commandName)
chris@3:   {
chris@3:     try
chris@3:     {
chris@3:       commandName = commandName.toUpperCase();
chris@3:       Command cmd = this.commandMapping.get(commandName);
chris@3: 
chris@3:       if(cmd == null)
chris@3:       {
cli@21:         Class<?> clazz = commandClassesMapping.get(commandName);
cli@21:         if(clazz == null)
cli@21:         {
cli@21:           cmd = this.unsupportedCmd;
cli@21:         }
cli@21:         else
cli@21:         {
cli@21:           cmd = (Command)clazz.newInstance();
cli@21:           this.commandMapping.put(commandName, cmd);
cli@21:         }
chris@3:       }
chris@3:       else if(cmd.isStateful())
chris@3:       {
cli@21:         cmd = cmd.getClass().newInstance();
chris@3:       }
cli@21: 
cli@21:       return cmd;
chris@3:     }
chris@3:     catch(Exception ex)
chris@3:     {
chris@3:       ex.printStackTrace();
chris@3:       return this.unsupportedCmd;
chris@3:     }
chris@3:   }
chris@3: 
chris@3: }