1 package com.atlassian.plugin.servlet;
2
3 import javax.servlet.Filter;
4 import javax.servlet.FilterConfig;
5 import javax.servlet.ServletConfig;
6 import javax.servlet.ServletContextListener;
7 import javax.servlet.ServletException;
8 import javax.servlet.http.HttpServlet;
9
10 import com.atlassian.plugin.servlet.descriptors.ServletFilterModuleDescriptor;
11 import com.atlassian.plugin.servlet.descriptors.ServletModuleDescriptor;
12 import com.atlassian.plugin.servlet.filter.FilterLocation;
13 import com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter;
14
15 /**
16 * The ServletModuleManager is responsible for servlets and filters - and their servlet contexts - defined in plugins.
17 * It is used by instances of the {@link ServletModuleContainerServlet} and {@link ServletFilterModuleContainerFilter}
18 * to lookup, create and wrap the filters and servlets defined in plugins.
19 * <p/>
20 * When the first {@link Filter} or {@link Servlet} is first accessed in a plugin, a new {@link ServletContext} is
21 * created for all the modules in the plugin to share. This is done by wrapping the applications
22 * {@link ServletContext}, creating a map of attributes that are local to the plugin that are shadowed by the
23 * applications {@link ServletContext} attributes, merging any servlet context init parameters from the plugin and the
24 * application, and then running through any {@link ServletContextListener}s defined by the plugin has calling their
25 * contextInitialized() methods.
26 * <p/>
27 * The shadowing of the the plugins {@link ServletContext}s attributes are shadowed by the applications attributes
28 * means that if an attribute does not exist in the plugin local attribute map, the applications attributes will be
29 * returned. The plugin is thereby prevented from modifying the base applications context attributes on an application
30 * wide scope and can instead only change them, but not remove them, on a local scope.
31 * <p/>
32 * The init parameters in the plugin will override parameters from the base applications servlet
33 * init parameters that have the same name.
34 * <p/>
35 * During the creation of Filters and Servlets, the {@link FilterConfig} and {@link ServletConfig} provided to
36 * Filters and Servlets contain the plugin local {@link ServletContext}, as described above,
37 * and provides access to the init parameters defined in the plugin xml for the Filter or Servlet.
38 * <p/>
39 * After being created, the filters and servlets are wrapped to ensure the the init(), service(), doFilter(),
40 * and destroy() methods and other methods defined in the Filter and Servlet interfaces are executed in the plugins
41 * {@link ClassLoader}.
42 * <p/>
43 * The plugins {@link ServletContext} is not destroyed until the plugin is disabled. It is also at this time that any
44 * {@link ServletContextListener}s will have their contextDestroyed() methods called.
45 */
46 public interface ServletModuleManager
47 {
48 /**
49 * Register a new servlet plugin module.
50 *
51 * @param descriptor Details of what the servlet class is and the path it should serve.
52 */
53 void addServletModule(ServletModuleDescriptor descriptor);
54
55 /**
56 * Return an instance of the HttpServlet that should be used to serve content matching the provided url path.
57 *
58 * @param path Path of the incoming request to serve.
59 * @param servletConfig ServletConfig given to the delegating servlet.
60 * @return HttpServlet that has been registered to serve up content matching the passed in path.
61 * @throws ServletException Thrown if there is a problem initializing the servlet to be returned.
62 */
63 HttpServlet getServlet(String path, final ServletConfig servletConfig) throws ServletException;
64
65 /**
66 * Remove a previously registered servlet plugin module. Requests that come in on the path described in the
67 * descriptor will no longer be served.
68 *
69 * @param descriptor Details of what servlet module to remove.
70 */
71 void removeServletModule(ServletModuleDescriptor descriptor);
72
73 /**
74 * Register a new filter plugin module.
75 *
76 * @param descriptor Details of what the filter class is and the path it should serve.
77 */
78 void addFilterModule(ServletFilterModuleDescriptor descriptor);
79
80 /**
81 * Returns the filters that have been registered to filter requests at the specified path matching the location
82 * in the filter stack.
83 *
84 * @param location Place in the applications filter stack the filters should be applied.
85 * @param pathInfo Path of the incoming request to filter.
86 * @param filterConfig FilterConfig given to the delegating filter.
87 * @return List of filters to be applied, already sorted by weight
88 * @throws ServletException Thrown if there is a problem initializing one of the filters to apply.
89 */
90 Iterable<Filter> getFilters(FilterLocation location, String pathInfo, FilterConfig filterConfig) throws ServletException;
91
92 /**
93 * Remove a previously registered filter plugin module. Requests that come in on the path described in the
94 * descriptor will no longer be served.
95 *
96 * @param descriptor Details of what filter module to remove.
97 */
98 void removeFilterModule(ServletFilterModuleDescriptor descriptor);
99 }