Java tutorial
/* * Copyright 2008 Alin Dreghiciu. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or * implied. * * See the License for the specific language governing permissions and * limitations under the License. */ package org.openanzo.servlet; import java.io.IOException; import java.net.URL; import java.util.Arrays; import java.util.Collection; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.RequestDispatcher; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.lang.NullArgumentException; import org.eclipse.jetty.util.URIUtil; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Serves the welcome files if the request path ends with "/". * * @author Alin Dreghiciu * @since 0.3.0, January 16, 2008 */ class WelcomeFilesFilter implements Filter { private static final Logger LOG = LoggerFactory.getLogger(WelcomeFilesFilter.class); /** * Aray of welcome files. */ private final String[] m_welcomeFiles; /** * True if the client should be rediected to welcome file or false if forwarded */ private final boolean m_redirect; /** * Filter config. */ private FilterConfig m_filterConfig; private final Collection<String> paths; /** * Creates a welcome files filter. * * @param welcomeFiles * array of welcome files * @param redirect * true if the client should be rediected to welcome file or false if forwarded * * @throws NullArgumentException * if: welcome files array is null or empty entries in array are null or empty entries in array start or end with "/" */ WelcomeFilesFilter(Collection<String> paths, final String[] welcomeFiles, boolean redirect) { this.paths = paths; if (welcomeFiles.length == 0) { throw new NullArgumentException("Welcome files is be empty"); } for (String welcomeFile : welcomeFiles) { if (welcomeFile == null || welcomeFile.trim().length() == 0) { throw new NullArgumentException("Welcome files entry is null or empty"); } if (welcomeFile.startsWith("/")) { throw new NullArgumentException("Welcome files entry [" + welcomeFile + "] starts with '/'"); } if (welcomeFile.endsWith("/")) { throw new NullArgumentException("Welcome files entry [" + welcomeFile + "] ends with '/'"); } } m_welcomeFiles = welcomeFiles; m_redirect = redirect; } /** * Store the filter config. * * @see Filter#init(FilterConfig) */ public void init(final FilterConfig filterConfig) throws ServletException { m_filterConfig = filterConfig; } /** * Serves the welcome files if request path ends with "/". * * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain) */ public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain) throws IOException, ServletException { LOG.debug("Apply welcome files filter..."); if (m_welcomeFiles.length > 0 && request instanceof HttpServletRequest) { String servletPath = (((HttpServletRequest) request).getServletPath()); String pathInfo = ((HttpServletRequest) request).getPathInfo(); LOG.debug("Servlet path: " + servletPath); LOG.debug("Path info: " + pathInfo); if ((pathInfo != null && pathInfo.endsWith("/")) || (servletPath != null && servletPath.endsWith("/"))) { final ServletContext servletContext = m_filterConfig.getServletContext(); for (String welcomeFile : m_welcomeFiles) { final String welcomePath = URIUtil.addPaths(servletPath, URIUtil.addPaths(pathInfo, welcomeFile)); final String welcomeResource = URIUtil.addPaths(pathInfo, welcomeFile); final URL welcomeFileUrl = servletContext.getResource(welcomeResource); if (welcomeFileUrl != null) { if (m_redirect && response instanceof HttpServletResponse) { ((HttpServletResponse) response).sendRedirect(welcomeFile); return; } else { final RequestDispatcher requestDispatcher = request.getRequestDispatcher(welcomePath); if (requestDispatcher != null) { requestDispatcher.forward(request, response); return; } } } } } else if ((pathInfo == null || pathInfo.length() == 0) && (servletPath != null && paths.contains(servletPath))) { final ServletContext servletContext = m_filterConfig.getServletContext(); for (String welcomeFile : m_welcomeFiles) { final String welcomePath = URIUtil.addPaths(servletPath, welcomeFile); final String welcomeResource = welcomeFile; final URL welcomeFileUrl = servletContext.getResource(welcomeResource); if (welcomeFileUrl != null) { if (m_redirect && response instanceof HttpServletResponse) { ((HttpServletResponse) response).sendRedirect(welcomePath); return; } else { final RequestDispatcher requestDispatcher = request.getRequestDispatcher(welcomePath); if (requestDispatcher != null) { requestDispatcher.forward(request, response); return; } } } } } } else { if (m_welcomeFiles.length == 0) { LOG.debug("Welcome filter not applied as there are no welcome files configured."); } if (!(request instanceof HttpServletRequest)) { LOG.debug("Welcome filter not applied as the request is not an " + HttpServletRequest.class.getSimpleName()); } } // if we are here means that the request was not handled by welcome files filter so, go on chain.doFilter(request, response); } /** * Does nothing. * * @see javax.servlet.Filter#destroy() */ public void destroy() { // does nothing } @Override public String toString() { return new StringBuilder().append(this.getClass().getSimpleName()).append("{").append("welcomeFiles=") .append(Arrays.toString(m_welcomeFiles)).append("}").toString(); } }