--- 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<LightPITModule> moduleInfo = Optional.empty();
-
- /**
- * The EL proxy is necessary, because the EL resolver cannot handle annotation properties.
- */
- private Optional<LightPITModule.ELProxy> 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<HttpMethod, Map<String, HandlerMethod>> 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<RequestMapping> 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<HandlerMethod> 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<List<String>> availableLanguages = Functions.availableLanguages(getServletContext()).map(Arrays::asList);
- Optional<Locale> 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<HandlerMethod> 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);
- }
-}