1 /**
2 * This file Copyright (c) 2011 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.objectfactory;
35
36 /**
37 * ComponentFactory that provides an instance by reading it from a repository. The instance is created only when it is
38 * needed and is recreated if its configuration changes in the repository.
39 *
40 * @param <T> the type of component this factory instantiates.
41 * @version $Id$
42 */
43 public class LazyObservedComponentFactory<T> implements ComponentFactory<T> {
44
45 private String repository;
46 private String path;
47 private Class<T> type;
48 private ObservedComponentFactory<T> observedComponentFactory;
49 private ComponentProvider componentProvider;
50
51 public LazyObservedComponentFactory(String repository, String path, Class<T> type, ComponentProvider componentProvider) {
52 this.repository = repository;
53 this.path = path;
54 this.type = type;
55 this.componentProvider = componentProvider;
56 }
57
58 @Override
59 public synchronized T newInstance() {
60 if (observedComponentFactory == null) {
61 observedComponentFactory = new ObservedComponentFactory<T>(repository, path, type, componentProvider);
62 }
63 return observedComponentFactory.newInstance();
64 }
65 }