1 /**
2 * This file Copyright (c) 2009-2016 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.imaging.caching;
35
36 import info.magnolia.imaging.ImageGenerator;
37 import info.magnolia.imaging.ParameterProvider;
38
39 import javax.jcr.Property;
40 import javax.jcr.RepositoryException;
41
42 /**
43 * Defines a CachingStrategy.
44 *
45 * @param <P> type of ParameterProvider's parameter
46 */
47 public interface CachingStrategy<P> {
48
49 /**
50 * Returns a unique path pertinent to the given generator and parameter to use for storing
51 * the generated image. Returns null if the implementation determines caching should not occur.
52 */
53 String getCachePath(ImageGenerator<ParameterProvider<P>> generator, ParameterProvider<P> parameterProvider);
54
55
56 /**
57 * Given the currently cached generated image, determine if CachingImageStreamer should
58 * regenerate the image. Implementations will most likely simply compare the timestamp
59 * with their parameter if applicable, or use some other mechanism.
60 */
61 boolean shouldRegenerate(Property cachedBinary, ParameterProvider<P> parameterProvider) throws RepositoryException;
62
63 }