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1   /*
2    * Wallace IMAP Server
3    * Copyright (C) 2004  Robert Newson
4    *
5    * This program is free software; you can redistribute it and/or
6    * modify it under the terms of the GNU General Public License
7    * as published by the Free Software Foundation; either version 2
8    * of the License, or (at your option) any later version.
9    *
10   * This program is distributed in the hope that it will be useful,
11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   * GNU General Public License for more details.
14   *
15   * You should have received a copy of the GNU General Public License
16   * along with this program; if not, write to the Free Software
17   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
18   */
19  package net.sf.wallace.commands;
20  
21  import javax.mail.MessagingException;
22  
23  import net.sf.wallace.Command;
24  import net.sf.wallace.InvalidStateException;
25  import net.sf.wallace.WallaceSession;
26  import net.sf.wallace.WallaceSessionState;
27  
28  /***
29   * A useful base class to aid enforcement of state restrictions.
30   * 
31   * @author rnewson
32   */
33  public abstract class AbstractCommand implements Command {
34  
35      public final void execute(final WallaceSession wallaceSession) throws InvalidStateException, MessagingException {
36          assertCurrentState(wallaceSession, getAcceptableStates());
37          onExecute(wallaceSession);
38      }
39  
40      protected abstract WallaceSessionState[] getAcceptableStates();
41  
42      protected abstract void onExecute(final WallaceSession wallaceSession) throws MessagingException;
43  
44      private final void assertCurrentState(final WallaceSession wallaceSession, final WallaceSessionState[] acceptableStates)
45              throws InvalidStateException {
46          boolean inBadState = true;
47  
48          for (WallaceSessionState acceptableState : acceptableStates) {
49              if (wallaceSession.getState() == acceptableState) {
50                  inBadState = false;
51              }
52          }
53          
54          if (inBadState) {
55              throw new InvalidStateException(wallaceSession, acceptableStates);
56          }
57      }
58  
59  }