01: /*
02: * This file is part of PFIXCORE.
03: *
04: * PFIXCORE is free software; you can redistribute it and/or modify
05: * it under the terms of the GNU Lesser General Public License as published by
06: * the Free Software Foundation; either version 2 of the License, or
07: * (at your option) any later version.
08: *
09: * PFIXCORE is distributed in the hope that it will be useful,
10: * but WITHOUT ANY WARRANTY; without even the implied warranty of
11: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12: * GNU Lesser General Public License for more details.
13: *
14: * You should have received a copy of the GNU Lesser General Public License
15: * along with PFIXCORE; if not, write to the Free Software
16: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17: *
18: */
19:
20: package de.schlund.pfixcore.workflow;
21:
22: import java.util.Iterator;
23: import java.util.Vector;
24:
25: import org.apache.log4j.Logger;
26:
27: /**
28: * Implements an observable ContextResource. Observers will be
29: * notified, by calling update(this), if the method notifiyObservers()
30: * is called.
31: *
32: * @author <a href="mailto:stieler@schlund.de">Thomas Stieler</a>
33: *
34: *
35: */
36:
37: public abstract class ObservableContextResourceImpl implements
38: ContextResource, ObservableContextResource {
39: private Vector<ContextResourceObserver> observers = new Vector<ContextResourceObserver>();
40: private Logger LOG = Logger.getLogger(this .getClass());
41:
42: /**
43: * Adds an observer to the list of registered observers.
44: *
45: * @param obj an <code>ContextResourceObserver</code> value
46: */
47: public synchronized void addObserver(ContextResourceObserver obj) {
48: LOG.debug("Adding observer " + obj.getClass().getName());
49: observers.add(obj);
50: }
51:
52: /**
53: * Notifies all registered observers by calling update(this).
54: *
55: */
56: public synchronized void notifyObservers() throws Exception {
57: Iterator<ContextResourceObserver> iter = observers.iterator();
58: while (iter.hasNext()) {
59: ContextResourceObserver obj = iter.next();
60: LOG.debug("Notify observer" + obj.getClass().getName());
61: obj.update(this );
62: LOG.debug("notify done..." + obj.getClass().getName());
63: }
64: }
65: }
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