diff -r cfc3d11884ad -r 27a0fdd7bca7 src/java/de/uapcore/lightpit/AbstractLightPITServlet.java --- a/src/java/de/uapcore/lightpit/AbstractLightPITServlet.java Sun Apr 08 16:51:15 2018 +0200 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,296 +0,0 @@ -/* - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. - * - * Copyright 2018 Mike Becker. All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions are met: - * - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" - * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE - * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR - * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF - * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS - * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN - * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) - * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE - * POSSIBILITY OF SUCH DAMAGE. - * - */ -package de.uapcore.lightpit; - -import java.io.IOException; -import java.lang.reflect.Method; -import java.lang.reflect.Modifier; -import java.util.Arrays; -import java.util.HashMap; -import java.util.List; -import java.util.Locale; -import java.util.Map; -import java.util.Optional; -import javax.servlet.ServletException; -import javax.servlet.http.HttpServlet; -import javax.servlet.http.HttpServletRequest; -import javax.servlet.http.HttpServletResponse; -import javax.servlet.http.HttpSession; -import org.slf4j.Logger; -import org.slf4j.LoggerFactory; - -/** - * A special implementation of a HTTPServlet which is focused on implementing - * the necessary functionality for {@link LightPITModule}s. - */ -public abstract class AbstractLightPITServlet extends HttpServlet { - - private static final Logger LOG = LoggerFactory.getLogger(AbstractLightPITServlet.class); - - private static final String HTML_FULL_DISPATCHER = Functions.jspPath("html_full"); - - /** - * Store a reference to the annotation for quicker access. - */ - private Optional moduleInfo = Optional.empty(); - - /** - * The EL proxy is necessary, because the EL resolver cannot handle annotation properties. - */ - private Optional moduleInfoELProxy = Optional.empty(); - - - @FunctionalInterface - private static interface HandlerMethod { - ResponseType apply(HttpServletRequest t, HttpServletResponse u) throws IOException, ServletException; - } - - /** - * Invocation mapping gathered from the {@link RequestMapping} annotations. - * - * Paths in this map must always start with a leading slash, although - * the specification in the annotation must not start with a leading slash. - * - * The reason for this is the different handling of empty paths in - * {@link HttpServletRequest#getPathInfo()}. - */ - private final Map> mappings = new HashMap<>(); - - /** - * Gives implementing modules access to the {@link ModuleManager}. - * @return the module manager - */ - protected final ModuleManager getModuleManager() { - return (ModuleManager) getServletContext().getAttribute(ModuleManager.SC_ATTR_NAME); - } - - /** - * Gives implementing modules access to the {@link DatabaseFacade}. - * @return the database facade - */ - protected final DatabaseFacade getDatabaseFacade() { - return (DatabaseFacade) getServletContext().getAttribute(DatabaseFacade.SC_ATTR_NAME); - } - - private ResponseType invokeMapping(Method method, HttpServletRequest req, HttpServletResponse resp) - throws IOException, ServletException { - try { - LOG.trace("invoke {}#{}", method.getDeclaringClass().getName(), method.getName()); - return (ResponseType) method.invoke(this, req, resp); - } catch (ReflectiveOperationException | ClassCastException ex) { - LOG.error(String.format("invocation of method %s failed", method.getName()), ex); - resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); - return ResponseType.NONE; - } - } - - @Override - public void init() throws ServletException { - moduleInfo = Optional.ofNullable(this.getClass().getAnnotation(LightPITModule.class)); - moduleInfoELProxy = moduleInfo.map(LightPITModule.ELProxy::convert); - - if (moduleInfo.isPresent()) { - scanForRequestMappings(); - } - - LOG.trace("{} initialized", getServletName()); - } - - private void scanForRequestMappings() { - try { - Method[] methods = getClass().getDeclaredMethods(); - for (Method method : methods) { - Optional mapping = Optional.ofNullable(method.getAnnotation(RequestMapping.class)); - if (mapping.isPresent()) { - if (!Modifier.isPublic(method.getModifiers())) { - LOG.warn("{} is annotated with {} but is not public", - method.getName(), RequestMapping.class.getSimpleName() - ); - continue; - } - if (Modifier.isAbstract(method.getModifiers())) { - LOG.warn("{} is annotated with {} but is abstract", - method.getName(), RequestMapping.class.getSimpleName() - ); - continue; - } - if (!ResponseType.class.isAssignableFrom(method.getReturnType())) { - LOG.warn("{} is annotated with {} but has the wrong return type - 'ResponseType' required", - method.getName(), RequestMapping.class.getSimpleName() - ); - continue; - } - - Class[] params = method.getParameterTypes(); - if (params.length == 2 - && HttpServletRequest.class.isAssignableFrom(params[0]) - && HttpServletResponse.class.isAssignableFrom(params[1])) { - - final String requestPath = "/"+mapping.get().requestPath(); - - if (mappings.computeIfAbsent(mapping.get().method(), k -> new HashMap<>()). - putIfAbsent(requestPath, - (req, resp) -> invokeMapping(method, req, resp)) != null) { - LOG.warn("{} {} has multiple mappings", - mapping.get().method(), - mapping.get().requestPath() - ); - } - - LOG.debug("{} {} maps to {}::{}", - mapping.get().method(), - requestPath, - getClass().getSimpleName(), - method.getName() - ); - } else { - LOG.warn("{} is annotated with {} but has the wrong parameters - (HttpServletRequest,HttpServletResponse) required", - method.getName(), RequestMapping.class.getSimpleName() - ); - } - } - } - } catch (SecurityException ex) { - LOG.error("Scan for request mappings on declared methods failed.", ex); - } - } - - @Override - public void destroy() { - mappings.clear(); - LOG.trace("{} destroyed", getServletName()); - } - - /** - * Sets the name of the dynamic fragment. - * - * It is sufficient to specify the name without any extension. The extension - * is added automatically if not specified. - * - * The fragment must be located in the dynamic fragments folder. - * - * @param req the servlet request object - * @param fragmentName the name of the fragment - * @see Constants#DYN_FRAGMENT_PATH_PREFIX - */ - public void setDynamicFragment(HttpServletRequest req, String fragmentName) { - req.setAttribute(Constants.REQ_ATTR_FRAGMENT, Functions.dynFragmentPath(fragmentName)); - } - - /** - * Specifies the name of an additional stylesheet used by the module. - * - * Setting an additional stylesheet is optional, but quite common for HTML - * output. - * - * It is sufficient to specify the name without any extension. The extension - * is added automatically if not specified. - * - * @param req the servlet request object - * @param stylesheet the name of the stylesheet - */ - public void setStylesheet(HttpServletRequest req, String stylesheet) { - req.setAttribute(Constants.REQ_ATTR_STYLESHEET, Functions.enforceExt(stylesheet, ".css")); - } - - private void forwardToFullView(HttpServletRequest req, HttpServletResponse resp) - throws IOException, ServletException { - - req.setAttribute(Constants.REQ_ATTR_MENU, getModuleManager().getMainMenu(getDatabaseFacade())); - req.getRequestDispatcher(HTML_FULL_DISPATCHER).forward(req, resp); - } - - private Optional findMapping(HttpMethod method, HttpServletRequest req) { - return Optional.ofNullable(mappings.get(method)).map( - (rm) -> rm.get(Optional.ofNullable(req.getPathInfo()).orElse("/")) - ); - } - - private void forwardAsSepcified(ResponseType type, HttpServletRequest req, HttpServletResponse resp) - throws ServletException, IOException { - switch (type) { - case NONE: return; - case HTML_FULL: - forwardToFullView(req, resp); - return; - // TODO: implement remaining response types - default: - // this code should be unreachable - LOG.error("ResponseType switch is not exhaustive - this is a bug!"); - throw new UnsupportedOperationException(); - } - } - - private void doProcess(HttpMethod method, HttpServletRequest req, HttpServletResponse resp) - throws ServletException, IOException { - - // Synchronize module information with database - getModuleManager().syncWithDatabase(getDatabaseFacade()); - - // choose the requested language as session language (if available) or fall back to english, otherwise - HttpSession session = req.getSession(); - if (session.getAttribute(Constants.SESSION_ATTR_LANGUAGE) == null) { - Optional> availableLanguages = Functions.availableLanguages(getServletContext()).map(Arrays::asList); - Optional reqLocale = Optional.of(req.getLocale()); - Locale sessionLocale = reqLocale.filter((rl) -> availableLanguages.map((al) -> al.contains(rl.getLanguage())).orElse(false)).orElse(Locale.ENGLISH); - session.setAttribute(Constants.SESSION_ATTR_LANGUAGE, sessionLocale); - LOG.debug("Settng language for new session {}: {}", session.getId(), sessionLocale.getDisplayLanguage()); - } else { - Locale sessionLocale = (Locale) session.getAttribute(Constants.SESSION_ATTR_LANGUAGE); - resp.setLocale(sessionLocale); - LOG.trace("Continuing session {} with language {}", session.getId(), sessionLocale); - } - - // set some internal request attributes - req.setAttribute(Constants.REQ_ATTR_PATH, Functions.fullPath(req)); - req.setAttribute(Constants.REQ_ATTR_MODULE_CLASSNAME, this.getClass().getName()); - moduleInfoELProxy.ifPresent((proxy) -> req.setAttribute(Constants.REQ_ATTR_MODULE_INFO, proxy)); - - - // call the handler, if available, or send an HTTP 404 error - Optional mapping = findMapping(method, req); - if (mapping.isPresent()) { - forwardAsSepcified(mapping.get().apply(req, resp), req, resp); - } else { - resp.sendError(HttpServletResponse.SC_NOT_FOUND); - } - } - - @Override - protected final void doGet(HttpServletRequest req, HttpServletResponse resp) - throws ServletException, IOException { - doProcess(HttpMethod.GET, req, resp); - } - - @Override - protected final void doPost(HttpServletRequest req, HttpServletResponse resp) - throws ServletException, IOException { - doProcess(HttpMethod.POST, req, resp); - } -}