1 /**
   2  * AUTOHIT 2003
   3  * Copyright Erich P Gatejen (c) 1989,1997,2003,2004
   4  * 
   5  * This program is free software; you can redistribute it and/or modify 
   6  * it under the terms of the GNU General Public License as published by 
   7  * the Free Software Foundation; either version 2 of the License, or (at
   8  * your option) any later version.
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  11  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  12  * more details.
  13  * 
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17  *
  18  * Additional license information can be found in the documentation.
  19  * @author Erich P Gatejen
  20  */
  21 package autohit.server.command;
  22 
  23 import java.util.Vector;
  24 
  25 import autohit.common.channels.Receipt;
  26 import autohit.server.ServerException;
  27 import autohit.server.SystemContext;
  28 
  29 /**
  30  * A LOCAL Command server. This one expects to be on the same system as the
  31  * issuing agent (though you may be able to cheat this.) It will cache the
  32  * command registry on load, so you'll need to dispose it and create a new one,
  33  * if you want to capture changes. It will use the root logger as the response
  34  * channel.
  35  * 
  36  * @author Erich P. Gatejen
  37  * @version 1.0 <i>Version History</i><code>EPG - Initial - 25Jul03 </code>
  38  */
  39 public class CommandServerLocal implements CommandServer {
  40 
  41 	private CommandRegistry commandRegistry;
  42 	//private Hashtable commandCache; // Command cache not supported now
  43 	private SystemContext sc = null;
  44 
  45 	public final static String RESPOND_FAILED = "FAILED";
  46 
  47 	/**
  48 	 * Initialize. You can call this as often as you want, but must be called
  49 	 * at least once.
  50 	 * 
  51 	 * @param c
  52 	 *           the SystemContext
  53 	 * @throws ServerException
  54 	 */
  55 	public void init(SystemContext c) throws ServerException {
  56 		commandRegistry = c.getCommandRegistry();
  57 		if (commandRegistry == null)
  58 			throw new ServerException(
  59 				"CommandServerLocal unable to get a CommandRegistry.  Unable to finish initialization and is invalid.",
  60 				ServerException.CODE_COMMAND_REGISTRY_FAULT);
  61 
  62 		// Always make this last. The sc is how we tell if this server is
  63 		// valid.
  64 		sc = c;
  65 	}
  66 
  67 	/**
  68 	 * Execute a command. Use default channel for response. If a response
  69 	 * injector is not specified in the CommandAtom, we'll use the
  70 	 * SystemContext root logger for the response channel.
  71 	 * 
  72 	 * @param cmd
  73 	 *           is a command atom
  74 	 * @throws ServerException
  75 	 * @return printable string of some form. not defined by the interface.
  76 	 */
  77 	public String execute(CommandAtom cmd) throws ServerException {
  78 
  79 		String result = RESPOND_FAILED;
  80 		if (sc == null)
  81 			throw new ServerException(
  82 				"CommandServerLocal not initialized before execute() called",
  83 				ServerException.CODE_SW_DETECTED_FAULT);
  84 
  85 		// Trap any spurious exceptions
  86 		try {
  87 
  88 			// instantiate it
  89 			Command co = (Command) commandRegistry.instance(cmd.numeric);
  90 
  91 			// Make sure it has a command list
  92 			Receipt rr;
  93 			if (cmd.thing instanceof Vector) {
  94 				rr = co.call(sc, (Vector) cmd.thing);
  95 
  96 			} else {
  97 				throw new ServerException(
  98 					"CommandServerLocal.execute() failed to start command, since the command did not have a command list (Vector).",
  99 					ServerException.CODE_COMMAND_ERROR);
 100 			}
 101 
 102 			// if the result is acceptable, return it
 103 			if (rr != null) {
 104 				result = rr.toString();
 105 			}
 106 
 107 		} catch (ServerException se) {
 108 			throw se;
 109 		} catch (Exception ee) {
 110 			throw new ServerException(
 111 				"CommandServerLocal.execute() failed to gross exception.  message=" + ee.getMessage(),
 112 				ServerException.CODE_COMMAND_FAULT);
 113 		}
 114 		return result;
 115 	}
 116 
 117 }