1 /**
2 * This file Copyright (c) 2011-2018 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.cms.filters;
35
36 import java.io.IOException;
37
38 import javax.servlet.FilterChain;
39 import javax.servlet.ServletException;
40 import javax.servlet.ServletRequest;
41 import javax.servlet.ServletResponse;
42 import javax.servlet.http.HttpServletRequest;
43
44
45 /**
46 * Dispatches requests onto Magnolias filter chain, if the filter chain is bypassed for this request it passes it on to
47 * the next filter in web.xml.
48 *
49 * @see FilterManager
50 * @see SafeDestroyMgnlFilterWrapper
51 */
52 public class MgnlFilterDispatcher {
53
54 private final SafeDestroyMgnlFilterWrapper.Switcher switcher = new SafeDestroyMgnlFilterWrapper.Switcher();
55
56 /**
57 * Calls the target filter if it matches the request otherwise passes the request on to the next filter in web.xml.
58 */
59 public void doDispatch(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
60 SafeDestroyMgnlFilterWrapper filterToUse = switcher.getFilterAndAcquireReadLock();
61 if (filterToUse == null) {
62 throw new ServletException("Filter chain not available");
63 }
64
65 try {
66 if (filterToUse.matches((HttpServletRequest) request)) {
67 filterToUse.doFilter(request, response, chain);
68 return;
69 }
70 } finally {
71 filterToUse.releaseReadLock();
72 }
73
74 // Pass request to next filter in web.xml without holding the read lock
75 chain.doFilter(request, response);
76 }
77
78 /**
79 * Replaces the current filter with a new one and returns the previous filter. See
80 * {@link info.magnolia.cms.filters.SafeDestroyMgnlFilterWrapper.Switcher#replaceFilter(SafeDestroyMgnlFilterWrapper)}
81 * for usage constraints on the returned filter.
82 */
83 public MgnlFilter replaceTargetFilter(MgnlFilter newFilter) {
84 return switcher.replaceFilter(newFilter != null ? new SafeDestroyMgnlFilterWrapper(newFilter) : null);
85 }
86
87 /**
88 * Returns the current target filter with a read lock held. The returned filter will not be destroyed before the
89 * read lock is released.
90 */
91 public SafeDestroyMgnlFilterWrapper getTargetFilterAndAcquireReadLock() {
92 return switcher.getFilterAndAcquireReadLock();
93 }
94
95 /**
96 * Returns the current target filter, the returned instance will be destroyed if the target filter is replaced.
97 *
98 * @see info.magnolia.cms.filters.SafeDestroyMgnlFilterWrapper.Switcher#getFilter()
99 */
100 public MgnlFilter getTargetFilter() {
101 SafeDestroyMgnlFilterWrapper filter = switcher.getFilter();
102 return filter != null ? filter.getTargetFilter() : null;
103 }
104 }