Java tutorial
/* * See the NOTICE file distributed with this work for additional * information regarding copyright ownership. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ package org.xwiki.portlet.controller; import java.io.UnsupportedEncodingException; import java.util.Collections; import java.util.Enumeration; import java.util.HashMap; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Set; import java.util.Stack; import javax.servlet.RequestDispatcher; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; import org.apache.commons.lang.ArrayUtils; import org.xwiki.portlet.util.QueryStringParser; /** * Wraps a servlet request object dispatched from a portlet. * * @version $Id$ */ public class DispatchedRequest extends HttpServletRequestWrapper { /** * The character encoding set through {@link #setCharacterEncoding(String)}. */ private String settedCharacterEncoding; /** * The stack that holds the information about all the dispatches that affected this request. */ private final Stack<RequestDispatchInfo> dispatchStack = new Stack<RequestDispatchInfo>(); /** * The stack of dispatch parameters. These parameters are extracted from the dispatch URL query string. If the * request was redirected then only these parameters are exposed. */ private final Stack<Map<String, String[]>> dispatchParametersStack = new Stack<Map<String, String[]>>(); /** * Flag indicating if the request was redirected, i.e. if the HTTP POST parameters are available or not. */ private final boolean redirected; /** * The object used to parse the query string of dispatch URLs. */ private final QueryStringParser queryStringParser = new QueryStringParser(); /** * Wraps the given request that has been dispatched from a portlet, exposing the query string parameters of the * initial request. * * @param request the request to be wrapped * @param exposeInitialQueryStringParameters {@code true} to expose the initial query string parameters, {@code * false} otherwise * @throws ServletException if wrapping the given request fails */ public DispatchedRequest(HttpServletRequest request, boolean exposeInitialQueryStringParameters) throws ServletException { super(request); redirected = false; if (exposeInitialQueryStringParameters) { dispatchParametersStack.push(listToArray(parseInitialQueryString())); } } /** * Wraps the given request and behaves as if it was redirected to the specified URL. * * @param request the request to be wrapped * @param redirectURL the redirect URL * @throws ServletException if wrapping the given request fails */ public DispatchedRequest(HttpServletRequest request, String redirectURL) throws ServletException { super(request); redirected = true; pushDispatch(new Dispatch(DispatchType.FORWARD, redirectURL)); } /** * {@inheritDoc} * <p> * We override the default implementation to overcome the fact that calling {@code getRequestURL()} on a servlet * request dispatched from a portlet returns {@code null}. See chapter * "PLT.19.3.4 Request and Response Objects for Included Servlets/JSPs from within the Render Method" in JSR286 * Portlet Specification. * * @see HttpServletRequestWrapper#getRequestURL() * @see org.apache.catalina.connector.Request#getRequestURL() */ public StringBuffer getRequestURL() { StringBuffer url = super.getRequestURL(); if (url != null) { return url; } url = new StringBuffer(); String scheme = getScheme(); int port = getServerPort(); if (port < 0) { // Work around for a java.net.URL bug. port = 80; } url.append(scheme); url.append("://"); url.append(getServerName()); if (("http".equals(scheme) && port != 80) || ("https".equals(scheme) && port != 443)) { url.append(':'); url.append(port); } url.append(getRequestURI()); return url; } /** * {@inheritDoc} * <p> * Default implementation returns {@code null} if the request was dispatched from a portlet's render method. We * override this method to return either the value set through {@link #setCharacterEncoding(String)} or the value * passed from a portlet's action processing method. * * @see HttpServletRequestWrapper#getCharacterEncoding() * @see HttpServletRequestWrapper#setCharacterEncoding(String) */ @Override public String getCharacterEncoding() { String characterEncoding = super.getCharacterEncoding(); if (characterEncoding == null) { characterEncoding = settedCharacterEncoding; } return characterEncoding; } /** * {@inheritDoc} * <p> * Default implementation does nothing if the request was dispatched from a portlet's render method. We override * this method to store the given character encoding. This way the behavior is consistent with what happens when the * request is not dispatched from a portlet. * * @see HttpServletRequestWrapper#setCharacterEncoding(String) */ @Override public void setCharacterEncoding(String characterEncoding) throws UnsupportedEncodingException { super.setCharacterEncoding(characterEncoding); this.settedCharacterEncoding = characterEncoding; } /** * {@inheritDoc} * <p> * We wrap the request dispatcher to be notified whenever this request is forwarded or included. We have to do this * in order to update the path info. * * @see HttpServletRequestWrapper#getRequestDispatcher(String) */ @Override public RequestDispatcher getRequestDispatcher(String path) { RequestDispatcher dispatcher = super.getRequestDispatcher(path); if (dispatcher != null) { return new NotifyingRequestDispatcher(dispatcher, this, path); } else { return null; } } /** * {@inheritDoc} * * @see HttpServletRequestWrapper#getRequestURI() */ @Override public String getRequestURI() { if (dispatchStack.isEmpty()) { return super.getRequestURI(); } else { return dispatchStack.peek().getRequestURI(); } } /** * {@inheritDoc} * * @see HttpServletRequestWrapper#getServletPath() */ @Override public String getServletPath() { if (dispatchStack.isEmpty()) { return super.getServletPath(); } else { return dispatchStack.peek().getServletPath(); } } /** * {@inheritDoc} * * @see HttpServletRequestWrapper#getPathInfo() */ @Override public String getPathInfo() { if (dispatchStack.isEmpty()) { return super.getPathInfo(); } else { return dispatchStack.peek().getPathInfo(); } } /** * {@inheritDoc} * * @see HttpServletRequestWrapper#getQueryString() */ @Override public String getQueryString() { if (dispatchStack.isEmpty()) { return super.getQueryString(); } else { return dispatchStack.peek().getQueryString(); } } /** * {@inheritDoc} * * @see HttpServletRequestWrapper#getParameter(String) */ @Override public String getParameter(String name) { String value = redirected ? null : super.getParameter(name); if (value == null) { String[] values = dispatchParametersStack.isEmpty() ? null : dispatchParametersStack.peek().get(name); return values != null ? values[0] : null; } return value; } /** * {@inheritDoc} * * @see HttpServletRequestWrapper#getParameterMap() */ @SuppressWarnings("unchecked") @Override public Map<String, String[]> getParameterMap() { Map<String, String[]> parameterMap = new HashMap<String, String[]>(); if (!redirected) { parameterMap.putAll(super.getParameterMap()); } if (!dispatchParametersStack.isEmpty()) { for (String parameter : dispatchParametersStack.peek().keySet()) { parameterMap.put(parameter, getParameterValues(parameter)); } } return Collections.unmodifiableMap(parameterMap); } /** * {@inheritDoc} * * @see HttpServletRequestWrapper#getParameterNames() */ @SuppressWarnings("unchecked") @Override public Enumeration<String> getParameterNames() { Set<String> parameterNames = new HashSet<String>(); if (!redirected) { parameterNames.addAll(super.getParameterMap().keySet()); } if (!dispatchParametersStack.isEmpty()) { parameterNames.addAll(dispatchParametersStack.peek().keySet()); } return Collections.enumeration(parameterNames); } /** * {@inheritDoc} * * @see HttpServletRequestWrapper#getParameterValues(String) */ @Override public String[] getParameterValues(String name) { String[] values = redirected ? null : super.getParameterValues(name); String[] dispatchValues = dispatchParametersStack.isEmpty() ? null : dispatchParametersStack.peek().get(name); return (String[]) ArrayUtils.addAll(values, dispatchValues); } /** * Push the given dispatch info on the top of the dispatch stack and update the request path info accordingly. * * @param dispatch the dispatch to put on the top of the dispatch stack * @throws ServletException if pushing the given dispatch fails */ void pushDispatch(Dispatch dispatch) throws ServletException { dispatchStack.push(parseDispatchPath(dispatch.getPath())); try { dispatchParametersStack .push(listToArray(queryStringParser.parse(getQueryString(), getCharacterEncoding()))); } catch (UnsupportedEncodingException e) { // Roll back. dispatchStack.pop(); throw new ServletException("Failed to decode the query string parameters of the dispatch.", e); } } /** * Remove the top of the dispatch stack and restore the request path info as it was before the latest dispatch. */ void popDispatch() { dispatchStack.pop(); dispatchParametersStack.pop(); } /** * Extracts the request dispatch info from the given path. * * @param path the path where the request has been dispatched * @return the request info changed as a result of the dispatch */ private RequestDispatchInfo parseDispatchPath(String path) { RequestDispatchInfo info = new RequestDispatchInfo(); // TODO: Find a reliable way to determine the servlet path. The current code works only if the request is // dispatched to the same servlet (w/o a different path info and query string). String currentServletPath = getServletPath(); info.setServletPath(path.startsWith(currentServletPath) ? currentServletPath : ""); int queryStringStart = path.indexOf('?'); if (queryStringStart < 0) { info.setPathInfo(path.substring(info.getServletPath().length())); info.setQueryString(""); } else { info.setPathInfo(path.substring(info.getServletPath().length(), queryStringStart)); info.setQueryString(path.substring(queryStringStart + 1)); } info.setRequestURI(getContextPath() + info.getServletPath() + info.getPathInfo()); // Follow servlet specification: return null if the URL doesn't have any extra path info. if (info.getPathInfo().length() == 0) { info.setPathInfo(null); } return info; } /** * Utility method for converting a map of lists into a map of arrays. * * @param mapOfList the map of lists to be converted * @return the map of arrays */ private Map<String, String[]> listToArray(Map<String, List<String>> mapOfList) { Map<String, String[]> mapOfArray = new HashMap<String, String[]>(); for (Map.Entry<String, List<String>> entry : mapOfList.entrySet()) { mapOfArray.put(entry.getKey(), entry.getValue().toArray(new String[] {})); } return mapOfArray; } /** * Parses the query string of the initial request that reached the portal. The request received by the dispatch * filter wraps the initial request and hides the initial query string which usually contains only portal related * information. In some cases the initial query string contains parameters set through JavaScript. The reason for * parsing the initial query string is to expose those parameters set from JavaScript. * * @return the map of initial query string parameters * @throws ServletException if decoding the parameters fails */ private Map<String, List<String>> parseInitialQueryString() throws ServletException { HttpServletRequest initialRequest = (HttpServletRequest) getRequest(); while (initialRequest instanceof HttpServletRequestWrapper) { initialRequest = (HttpServletRequest) ((HttpServletRequestWrapper) initialRequest).getRequest(); } if (initialRequest.getQueryString() != null) { try { return queryStringParser.parse(initialRequest.getQueryString(), initialRequest.getCharacterEncoding()); } catch (UnsupportedEncodingException e) { throw new ServletException("Failed to decode the initial query string parameters.", e); } } else { return Collections.emptyMap(); } } }