1 /**
2 * This file Copyright (c) 2011-2015 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 import javax.servlet.FilterChain;
38 import javax.servlet.ServletException;
39 import javax.servlet.ServletRequest;
40 import javax.servlet.ServletResponse;
41 import javax.servlet.http.HttpServletRequest;
42
43
44 /**
45 * Dispatches requests onto Magnolias filter chain, if the filter chain is bypassed for this request it passes it on to
46 * the next filter in web.xml.
47 *
48 * @see FilterManager
49 * @see SafeDestroyMgnlFilterWrapper
50 */
51 public class MgnlFilterDispatcher {
52
53 private final SafeDestroyMgnlFilterWrapper.Switcher switcher = new SafeDestroyMgnlFilterWrapper.Switcher();
54
55 /**
56 * Calls the target filter if it matches the request otherwise passes the request on to the next filter in web.xml.
57 */
58 public void doDispatch(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
59 SafeDestroyMgnlFilterWrapper filterToUse = switcher.getFilterAndAcquireReadLock();
60 if (filterToUse == null) {
61 throw new ServletException("Filter chain not available");
62 }
63
64 try {
65 if (filterToUse.matches((HttpServletRequest) request)) {
66 filterToUse.doFilter(request, response, chain);
67 return;
68 }
69 } finally {
70 filterToUse.releaseReadLock();
71 }
72
73 // Pass request to next filter in web.xml without holding the read lock
74 chain.doFilter(request, response);
75 }
76
77 /**
78 * Replaces the current filter with a new one and returns the previous filter. See
79 * {@link info.magnolia.cms.filters.SafeDestroyMgnlFilterWrapper.Switcher#replaceFilter(SafeDestroyMgnlFilterWrapper)}
80 * for usage constraints on the returned filter.
81 */
82 public MgnlFilter replaceTargetFilter(MgnlFilter newFilter) {
83 return switcher.replaceFilter(newFilter != null ? new SafeDestroyMgnlFilterWrapper(newFilter) : null);
84 }
85
86 /**
87 * Returns the current target filter with a read lock held. The returned filter will not be destroyed before the
88 * read lock is released.
89 */
90 public SafeDestroyMgnlFilterWrapper getTargetFilterAndAcquireReadLock() {
91 return switcher.getFilterAndAcquireReadLock();
92 }
93
94 /**
95 * Returns the current target filter, the returned instance will be destroyed if the target filter is replaced.
96 *
97 * @see info.magnolia.cms.filters.SafeDestroyMgnlFilterWrapper.Switcher#getFilter()
98 */
99 public MgnlFilter getTargetFilter() {
100 SafeDestroyMgnlFilterWrapper filter = switcher.getFilter();
101 return filter != null ? filter.getTargetFilter() : null;
102 }
103 }