trunk/chemistry-opencmis-test/chemistry-opencmis-test-browser/src/main/java/org/apache/chemistry/opencmis/browser/BrowseServlet.java - chemistry-opencmis - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you 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.apache.chemistry.opencmis.browser;

 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.PrintWriter;
 import java.net.HttpURLConnection;
 import java.net.URL;
 import java.net.URLDecoder;
 import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.Map;

 import javax.servlet.ServletConfig;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.transform.Result;
 import javax.xml.transform.Source;
 import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerFactory;
 import javax.xml.transform.dom.DOMSource;
 import javax.xml.transform.stream.StreamResult;
 import javax.xml.transform.stream.StreamSource;

 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.w3c.dom.Document;

 /**
  * CMIS Browser Servlet.
  */
 public class BrowseServlet extends HttpServlet {

     private static final long serialVersionUID = 1L;

     private static final Logger LOG = LoggerFactory.getLogger(BrowseServlet.class);

     private static final String CONTEXT_PREFIX = "{ctx}";
     private static final String PARAM_URL = "url";
     private static final String PARAM_OVERRIDE_STYLESHEET = "overrideStylesheet";
     private static final int PARAM_URL_MIN_LEN = PARAM_URL.length() + "=".length() + "http".length() + "://".length()
             + 1;
     private static final String INIT_PARAM_AUXROOT = "auxroot";
     private static final String INIT_PARAM_ALLOW = "allow";
     private static final String INIT_PARAM_STYLESHEET = "stylesheet:";
     private static final String INIT_PARAM_OVERRIDE_STYLESHEET = "override-stylesheet:";

     private static final int BUFFER_SIZE = 64 * 1024;

     private String fAuxRoot = "";
     private String fAllow = ".*";
     private Map<String, Source> fStyleSheets;
     private Map<String, Source> fOverrideStyleSheets;

     /**
      * Initializes the browser servlet.
      */
     @SuppressWarnings("unchecked")
     @Override
     public void init(ServletConfig config) throws ServletException {
         fStyleSheets = new HashMap<String, Source>();
         fOverrideStyleSheets = new HashMap<String, Source>();

         DocumentBuilder builder = null;
         try {
             DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
             builderFactory.setNamespaceAware(true);
             builder = builderFactory.newDocumentBuilder();
         } catch (Exception e) {
             LOG.error(e.getMessage(), e);
             return;
         }

         Enumeration<String> initParams = config.getInitParameterNames();
         while (initParams.hasMoreElements()) {
             String param = initParams.nextElement();
             String stylesheetKey = null;
             boolean isOverride = false;

             if (param.startsWith(INIT_PARAM_STYLESHEET)) {
                 stylesheetKey = param.substring(INIT_PARAM_STYLESHEET.length());
             } else if (param.startsWith(INIT_PARAM_OVERRIDE_STYLESHEET)) {
                 stylesheetKey = param.substring(INIT_PARAM_OVERRIDE_STYLESHEET.length());
                 isOverride = true;
             }

             if (stylesheetKey != null) {
                 String stylesheetFileName = config.getInitParameter(param);
                 InputStream stream = config.getServletContext().getResourceAsStream(stylesheetFileName);
                 if (stream != null) {
                     try {
                         Document xslDoc = builder.parse(stream);
                         addStylesheet(stylesheetKey, new DOMSource(xslDoc), isOverride);

                         LOG.info("Stylesheet: '" + stylesheetKey + "' -> '" + stylesheetFileName + "'");
                     } catch (Exception e) {
                         LOG.error(e.getMessage(), e);
                     }
                 }
             }
         }

         String initAuxRoot = config.getInitParameter(INIT_PARAM_AUXROOT);
         if (initAuxRoot != null) {
             fAuxRoot = initAuxRoot;
             LOG.info("Auxiliary root: " + fAuxRoot);
         }

         String initAllow = config.getInitParameter(INIT_PARAM_ALLOW);
         if (initAllow != null) {
             fAllow = initAllow;
             LOG.info("Allow pattern: " + fAllow);
         }
     }

     /**
      * Handles GET requests.
      */
     @Override
     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
         String browseUrl = null;
         String overrideStylesheet = null;

         // The url parameter must come first!
         String queryString = req.getQueryString();

         if ((queryString != null) && (queryString.startsWith(PARAM_URL))) {
             int urlEnd = queryString.indexOf(PARAM_OVERRIDE_STYLESHEET + "=");
             if (urlEnd == -1) {
                 urlEnd = queryString.length();
             } else {
                 overrideStylesheet = queryString.substring(urlEnd + PARAM_OVERRIDE_STYLESHEET.length() + 1);
                 --urlEnd;
             }

             browseUrl = queryString.substring(PARAM_URL.length() + 1, urlEnd);

             if (browseUrl.length() < PARAM_URL_MIN_LEN) {
                 browseUrl = null;
             }
         }

         if (browseUrl == null) {
             printInput(req, resp);
             return;
         }

         doBrowse(req, resp, browseUrl, overrideStylesheet);
     }

     /**
      * Main method of the browser.
      */
     protected void doBrowse(HttpServletRequest req, HttpServletResponse resp, String browseUrl,
             String overrideStylesheet) throws ServletException, IOException {
         // check if decoding is necessary
         // (if the char after 'http' or 'https' is not a colon, then it must be
         // decoded)
         if (browseUrl.charAt(4) != ':' && browseUrl.charAt(5) != ':') {
             browseUrl = URLDecoder.decode(browseUrl, "UTF-8");
         }

         // check URL
         if (!browseUrl.matches(fAllow)) {
             printError(req, resp, "Prohibited URL!", null);
             return;
         }

         try {
             // get content
             URL url = new URL(browseUrl);
             HttpURLConnection conn = (HttpURLConnection) url.openConnection();
             conn.setDoInput(true);
             conn.setDoOutput(false);
             conn.setRequestMethod("GET");
             String authHeader = req.getHeader("Authorization");
             if (authHeader != null) {
                 conn.setRequestProperty("Authorization", authHeader);
             }
             conn.connect();

             // ask for login
             if (conn.getResponseCode() == HttpURLConnection.HTTP_UNAUTHORIZED) {
                 resp.setHeader("WWW-Authenticate", conn.getHeaderField("WWW-Authenticate"));
                 resp.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Authorization Required");
                 return;
             }

             // debug messages
             if (LOG.isDebugEnabled()) {
                 LOG.debug("'" + browseUrl + "' -> '" + conn.getContentType() + "'");
             }

             // find stylesheet
             Source stylesheet = getStylesheet(conn.getContentType(), overrideStylesheet);

             OutputStream out = null;
             InputStream in = new BufferedInputStream(conn.getInputStream(), BUFFER_SIZE);

             if (stylesheet == null) {
                 // no stylesheet found -> conduct content
                 resp.setContentType(conn.getContentType());
                 out = new BufferedOutputStream(resp.getOutputStream(), BUFFER_SIZE);

                 byte[] buffer = new byte[BUFFER_SIZE];
                 int b;
                 while ((b = in.read(buffer)) > -1) {
                     out.write(buffer, 0, b);
                 }
             } else {
                 // apply stylesheet
                 TransformerFactory f = TransformerFactory.newInstance();
                 Transformer t = f.newTransformer(stylesheet);
                 t.setParameter("browseUrl", getServletUrl(req) + "?" + PARAM_URL + "=");
                 t.setParameter("auxRoot", getAuxRoot(req, fAuxRoot));
                 t.setParameter("browseOverrideStylesheet", "&" + PARAM_OVERRIDE_STYLESHEET + "=");

                 resp.setContentType("text/html");
                 out = new BufferedOutputStream(resp.getOutputStream(), BUFFER_SIZE);

                 Source s = new StreamSource(in);
                 Result r = new StreamResult(out);
                 t.transform(s, r);
             }

             try {
                 out.flush();
                 out.close();
             } catch (Exception e) {
                 // ignore, there isn't anything we can do
             }

             try {
                 in.close();
             } catch (Exception e) {
                 // ignore, there isn't anything we can do
             }
         } catch (Exception e) {
             printError(req, resp, e.getMessage(), e);
             return;
         }
     }

     // ---- utilities ----

     /**
      * Assigns a stylesheet to a content type.
      */
     private void addStylesheet(String contentType, Source source, boolean override) {
         if ((contentType == null) || (source == null)) {
             return;
         }

         if (override) {
             fOverrideStyleSheets.put(contentType.trim().toLowerCase(), source);
         } else {
             fStyleSheets.put(contentType.trim().toLowerCase(), source);
         }
     }

     /**
      * Returns the stylesheet for the given override stylesheet, if there is is
      * not override stylesheet given then the stylesheet for the given content
      * type or <code>null</code> if no stylesheet is assigned to content type.
      */
     private Source getStylesheet(String contentType, String overrideStylesheet) {
         if (contentType == null) {
             return null;
         }

         Source source = null;

         // First check if there is an override given and it has a match.
         if (overrideStylesheet != null && overrideStylesheet.length() > 0) {
             source = fOverrideStyleSheets.get(overrideStylesheet);
         }

         // If there is not match then check the content type map.
         if (source == null) {
             String[] ctp = contentType.trim().toLowerCase().split(";");

             StringBuilder match = new StringBuilder();
             int i = 0;
             while (source == null && i < ctp.length) {
                 if (i > 0) {
                     match.append(";");
                 }
                 match.append(ctp[i]);
                 source = fStyleSheets.get(match.toString());
                 i++;
             }
         }

         return source;
     }

     /**
      * Returns the context URL of this servlet.
      */
     private String getContextUrl(HttpServletRequest request) {
         String scheme = request.getScheme();
         int port = request.getServerPort();

         if ("http".equals(scheme) && (port == 80)) {
             port = -1;
         }
         if ("https".equals(scheme) && (port == 443)) {
             port = -1;
         }

         return scheme + "://" + request.getServerName() + (port > 0 ? ":" + port : "") + request.getContextPath();
     }

     /**
      * Returns the URL of this servlet.
      */
     private String getServletUrl(HttpServletRequest request) {
         return getContextUrl(request) + request.getServletPath();
     }

     /**
      * Returns the root URL of auxiliary files.
      */
     private String getAuxRoot(HttpServletRequest request, String auxRoot) {
         if (auxRoot == null) {
             return getContextUrl(request);
         } else if (auxRoot.startsWith(CONTEXT_PREFIX)) {
             return getContextUrl(request) + auxRoot.substring(CONTEXT_PREFIX.length());
         } else {
             return auxRoot;
         }
     }

     // --- HTML methods ----

     /**
      * Prints a HTML header with styles.
      */
     private void printHeader(PrintWriter pw, String title) {
         pw.print("<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\"");
         pw.println("\"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">");
         pw.println("<html xmlns=\"http://www.w3.org/1999/xhtml\">");
         pw.println("<head>");
         pw.println("<title>" + title + "</title>");
         pw.println("<meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\" />");
         pw.println("<style type=\"text/css\">");
         pw.println("body { font-family: arial,sans-serif; font-size: 10pt; }");
         pw.println("div.box { background-color: #f6f1de; margin-top: 10px;"
                 + " margin-bottom: 10px; margin-left: 0px; margin-right: 0px;"
                 + " padding: 5px; border-style: solid; border-width: 1px; border-color: #888a85; }");
         pw.println("</style>");
         pw.println("</head>");
         pw.println("<body>");
     }

     /**
      * Prints a HTML footer.
      */
     private void printFooter(PrintWriter pw) {
         pw.println("</body>");
         pw.println("</html>");
     }

     /**
      * Prints a HTML error message.
      */
     private void printError(HttpServletRequest req, HttpServletResponse resp, String message, Exception e)
             throws IOException {
         resp.setContentType("text/html;charset=utf-8");
         PrintWriter pw = resp.getWriter();

         printHeader(pw, "Error");
         pw.println("<div class=\"box\">");
         pw.println("<h3>" + message + "</h3>");

         if (e != null) {
             pw.print("<pre>");
             e.printStackTrace(pw);
             pw.println("</pre>");
         }

         pw.println("</div>");
         printFooter(pw);
     }

     /**
      * Prints an HTML input box.
      */
     private void printInput(HttpServletRequest req, HttpServletResponse resp) throws IOException {
         resp.setContentType("text/html;charset=utf-8");
         PrintWriter pw = resp.getWriter();

         printHeader(pw, "OpenCMIS Browser");
         pw.println("<img src=\"" + getAuxRoot(req, fAuxRoot) + "cmis.png\" " + "style=\"float: right;\" />");
         pw.println("<h1 style=\"font-family: Georgia;\">OpenCMIS Browser</h1>");
         pw.println("<div class=\"box\">");
         pw.println("<form action=\"\" method=\"GET\">");
         pw.println("CMIS AtomPub URL: ");
         pw.println("<input name=\"url\" type=\"text\" size=\"100\" value=\"\"/>");
         pw.println("<input type=\"submit\" value=\" GO \"/>");
         pw.println("</form>");
         pw.println("</div>");
         printFooter(pw);
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you 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.apache.chemistry.opencmis.browser;

	import java.io.BufferedInputStream;
	import java.io.BufferedOutputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;
	import java.io.PrintWriter;
	import java.net.HttpURLConnection;
	import java.net.URL;
	import java.net.URLDecoder;
	import java.util.Enumeration;
	import java.util.HashMap;
	import java.util.Map;

	import javax.servlet.ServletConfig;
	import javax.servlet.ServletException;
	import javax.servlet.http.HttpServlet;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;
	import javax.xml.parsers.DocumentBuilder;
	import javax.xml.parsers.DocumentBuilderFactory;
	import javax.xml.transform.Result;
	import javax.xml.transform.Source;
	import javax.xml.transform.Transformer;
	import javax.xml.transform.TransformerFactory;
	import javax.xml.transform.dom.DOMSource;
	import javax.xml.transform.stream.StreamResult;
	import javax.xml.transform.stream.StreamSource;

	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;
	import org.w3c.dom.Document;

	/**
	* CMIS Browser Servlet.
	*/
	public class BrowseServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	private static final Logger LOG = LoggerFactory.getLogger(BrowseServlet.class);

	private static final String CONTEXT_PREFIX = "{ctx}";
	private static final String PARAM_URL = "url";
	private static final String PARAM_OVERRIDE_STYLESHEET = "overrideStylesheet";
	private static final int PARAM_URL_MIN_LEN = PARAM_URL.length() + "=".length() + "http".length() + "://".length()
	+ 1;
	private static final String INIT_PARAM_AUXROOT = "auxroot";
	private static final String INIT_PARAM_ALLOW = "allow";
	private static final String INIT_PARAM_STYLESHEET = "stylesheet:";
	private static final String INIT_PARAM_OVERRIDE_STYLESHEET = "override-stylesheet:";

	private static final int BUFFER_SIZE = 64 * 1024;

	private String fAuxRoot = "";
	private String fAllow = ".*";
	private Map<String, Source> fStyleSheets;
	private Map<String, Source> fOverrideStyleSheets;

	/**
	* Initializes the browser servlet.
	*/
	@SuppressWarnings("unchecked")
	@Override
	public void init(ServletConfig config) throws ServletException {
	fStyleSheets = new HashMap<String, Source>();
	fOverrideStyleSheets = new HashMap<String, Source>();

	DocumentBuilder builder = null;
	try {
	DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
	builderFactory.setNamespaceAware(true);
	builder = builderFactory.newDocumentBuilder();
	} catch (Exception e) {
	LOG.error(e.getMessage(), e);
	return;
	}

	Enumeration<String> initParams = config.getInitParameterNames();
	while (initParams.hasMoreElements()) {
	String param = initParams.nextElement();
	String stylesheetKey = null;
	boolean isOverride = false;

	if (param.startsWith(INIT_PARAM_STYLESHEET)) {
	stylesheetKey = param.substring(INIT_PARAM_STYLESHEET.length());
	} else if (param.startsWith(INIT_PARAM_OVERRIDE_STYLESHEET)) {
	stylesheetKey = param.substring(INIT_PARAM_OVERRIDE_STYLESHEET.length());
	isOverride = true;
	}

	if (stylesheetKey != null) {
	String stylesheetFileName = config.getInitParameter(param);
	InputStream stream = config.getServletContext().getResourceAsStream(stylesheetFileName);
	if (stream != null) {
	try {
	Document xslDoc = builder.parse(stream);
	addStylesheet(stylesheetKey, new DOMSource(xslDoc), isOverride);

	LOG.info("Stylesheet: '" + stylesheetKey + "' -> '" + stylesheetFileName + "'");
	} catch (Exception e) {
	LOG.error(e.getMessage(), e);
	}
	}
	}
	}

	String initAuxRoot = config.getInitParameter(INIT_PARAM_AUXROOT);
	if (initAuxRoot != null) {
	fAuxRoot = initAuxRoot;
	LOG.info("Auxiliary root: " + fAuxRoot);
	}

	String initAllow = config.getInitParameter(INIT_PARAM_ALLOW);
	if (initAllow != null) {
	fAllow = initAllow;
	LOG.info("Allow pattern: " + fAllow);
	}
	}

	/**
	* Handles GET requests.
	*/
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	String browseUrl = null;
	String overrideStylesheet = null;

	// The url parameter must come first!
	String queryString = req.getQueryString();

	if ((queryString != null) && (queryString.startsWith(PARAM_URL))) {
	int urlEnd = queryString.indexOf(PARAM_OVERRIDE_STYLESHEET + "=");
	if (urlEnd == -1) {
	urlEnd = queryString.length();
	} else {
	overrideStylesheet = queryString.substring(urlEnd + PARAM_OVERRIDE_STYLESHEET.length() + 1);
	--urlEnd;
	}

	browseUrl = queryString.substring(PARAM_URL.length() + 1, urlEnd);

	if (browseUrl.length() < PARAM_URL_MIN_LEN) {
	browseUrl = null;
	}
	}

	if (browseUrl == null) {
	printInput(req, resp);
	return;
	}

	doBrowse(req, resp, browseUrl, overrideStylesheet);
	}

	/**
	* Main method of the browser.
	*/
	protected void doBrowse(HttpServletRequest req, HttpServletResponse resp, String browseUrl,
	String overrideStylesheet) throws ServletException, IOException {
	// check if decoding is necessary
	// (if the char after 'http' or 'https' is not a colon, then it must be
	// decoded)
	if (browseUrl.charAt(4) != ':' && browseUrl.charAt(5) != ':') {
	browseUrl = URLDecoder.decode(browseUrl, "UTF-8");
	}

	// check URL
	if (!browseUrl.matches(fAllow)) {
	printError(req, resp, "Prohibited URL!", null);
	return;
	}

	try {
	// get content
	URL url = new URL(browseUrl);
	HttpURLConnection conn = (HttpURLConnection) url.openConnection();
	conn.setDoInput(true);
	conn.setDoOutput(false);
	conn.setRequestMethod("GET");
	String authHeader = req.getHeader("Authorization");
	if (authHeader != null) {
	conn.setRequestProperty("Authorization", authHeader);
	}
	conn.connect();

	// ask for login
	if (conn.getResponseCode() == HttpURLConnection.HTTP_UNAUTHORIZED) {
	resp.setHeader("WWW-Authenticate", conn.getHeaderField("WWW-Authenticate"));
	resp.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Authorization Required");
	return;
	}

	// debug messages
	if (LOG.isDebugEnabled()) {
	LOG.debug("'" + browseUrl + "' -> '" + conn.getContentType() + "'");
	}

	// find stylesheet
	Source stylesheet = getStylesheet(conn.getContentType(), overrideStylesheet);

	OutputStream out = null;
	InputStream in = new BufferedInputStream(conn.getInputStream(), BUFFER_SIZE);

	if (stylesheet == null) {
	// no stylesheet found -> conduct content
	resp.setContentType(conn.getContentType());
	out = new BufferedOutputStream(resp.getOutputStream(), BUFFER_SIZE);

	byte[] buffer = new byte[BUFFER_SIZE];
	int b;
	while ((b = in.read(buffer)) > -1) {
	out.write(buffer, 0, b);
	}
	} else {
	// apply stylesheet
	TransformerFactory f = TransformerFactory.newInstance();
	Transformer t = f.newTransformer(stylesheet);
	t.setParameter("browseUrl", getServletUrl(req) + "?" + PARAM_URL + "=");
	t.setParameter("auxRoot", getAuxRoot(req, fAuxRoot));
	t.setParameter("browseOverrideStylesheet", "&" + PARAM_OVERRIDE_STYLESHEET + "=");

	resp.setContentType("text/html");
	out = new BufferedOutputStream(resp.getOutputStream(), BUFFER_SIZE);

	Source s = new StreamSource(in);
	Result r = new StreamResult(out);
	t.transform(s, r);
	}

	try {
	out.flush();
	out.close();
	} catch (Exception e) {
	// ignore, there isn't anything we can do
	}

	try {
	in.close();
	} catch (Exception e) {
	// ignore, there isn't anything we can do
	}
	} catch (Exception e) {
	printError(req, resp, e.getMessage(), e);
	return;
	}
	}

	// ---- utilities ----

	/**
	* Assigns a stylesheet to a content type.
	*/
	private void addStylesheet(String contentType, Source source, boolean override) {
	if ((contentType == null) \|\| (source == null)) {
	return;
	}

	if (override) {
	fOverrideStyleSheets.put(contentType.trim().toLowerCase(), source);
	} else {
	fStyleSheets.put(contentType.trim().toLowerCase(), source);
	}
	}

	/**
	* Returns the stylesheet for the given override stylesheet, if there is is
	* not override stylesheet given then the stylesheet for the given content
	* type or <code>null</code> if no stylesheet is assigned to content type.
	*/
	private Source getStylesheet(String contentType, String overrideStylesheet) {
	if (contentType == null) {
	return null;
	}

	Source source = null;

	// First check if there is an override given and it has a match.
	if (overrideStylesheet != null && overrideStylesheet.length() > 0) {
	source = fOverrideStyleSheets.get(overrideStylesheet);
	}

	// If there is not match then check the content type map.
	if (source == null) {
	String[] ctp = contentType.trim().toLowerCase().split(";");

	StringBuilder match = new StringBuilder();
	int i = 0;
	while (source == null && i < ctp.length) {
	if (i > 0) {
	match.append(";");
	}
	match.append(ctp[i]);
	source = fStyleSheets.get(match.toString());
	i++;
	}
	}

	return source;
	}

	/**
	* Returns the context URL of this servlet.
	*/
	private String getContextUrl(HttpServletRequest request) {
	String scheme = request.getScheme();
	int port = request.getServerPort();

	if ("http".equals(scheme) && (port == 80)) {
	port = -1;
	}
	if ("https".equals(scheme) && (port == 443)) {
	port = -1;
	}

	return scheme + "://" + request.getServerName() + (port > 0 ? ":" + port : "") + request.getContextPath();
	}

	/**
	* Returns the URL of this servlet.
	*/
	private String getServletUrl(HttpServletRequest request) {
	return getContextUrl(request) + request.getServletPath();
	}

	/**
	* Returns the root URL of auxiliary files.
	*/
	private String getAuxRoot(HttpServletRequest request, String auxRoot) {
	if (auxRoot == null) {
	return getContextUrl(request);
	} else if (auxRoot.startsWith(CONTEXT_PREFIX)) {
	return getContextUrl(request) + auxRoot.substring(CONTEXT_PREFIX.length());
	} else {
	return auxRoot;
	}
	}

	// --- HTML methods ----

	/**
	* Prints a HTML header with styles.
	*/
	private void printHeader(PrintWriter pw, String title) {
	pw.print("<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\"");
	pw.println("\"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">");
	pw.println("<html xmlns=\"http://www.w3.org/1999/xhtml\">");
	pw.println("<head>");
	pw.println("<title>" + title + "</title>");
	pw.println("<meta http-equiv=\"content-type\" content=\"text/html; charset=UTF-8\" />");
	pw.println("<style type=\"text/css\">");
	pw.println("body { font-family: arial,sans-serif; font-size: 10pt; }");
	pw.println("div.box { background-color: #f6f1de; margin-top: 10px;"
	+ " margin-bottom: 10px; margin-left: 0px; margin-right: 0px;"
	+ " padding: 5px; border-style: solid; border-width: 1px; border-color: #888a85; }");
	pw.println("</style>");
	pw.println("</head>");
	pw.println("<body>");
	}

	/**
	* Prints a HTML footer.
	*/
	private void printFooter(PrintWriter pw) {
	pw.println("</body>");
	pw.println("</html>");
	}

	/**
	* Prints a HTML error message.
	*/
	private void printError(HttpServletRequest req, HttpServletResponse resp, String message, Exception e)
	throws IOException {
	resp.setContentType("text/html;charset=utf-8");
	PrintWriter pw = resp.getWriter();

	printHeader(pw, "Error");
	pw.println("<div class=\"box\">");
	pw.println("<h3>" + message + "</h3>");

	if (e != null) {
	pw.print("<pre>");
	e.printStackTrace(pw);
	pw.println("</pre>");
	}

	pw.println("</div>");
	printFooter(pw);
	}

	/**
	* Prints an HTML input box.
	*/
	private void printInput(HttpServletRequest req, HttpServletResponse resp) throws IOException {
	resp.setContentType("text/html;charset=utf-8");
	PrintWriter pw = resp.getWriter();

	printHeader(pw, "OpenCMIS Browser");
	pw.println("<img src=\"" + getAuxRoot(req, fAuxRoot) + "cmis.png\" " + "style=\"float: right;\" />");
	pw.println("<h1 style=\"font-family: Georgia;\">OpenCMIS Browser</h1>");
	pw.println("<div class=\"box\">");
	pw.println("<form action=\"\" method=\"GET\">");
	pw.println("CMIS AtomPub URL: ");
	pw.println("<input name=\"url\" type=\"text\" size=\"100\" value=\"\"/>");
	pw.println("<input type=\"submit\" value=\" GO \"/>");
	pw.println("</form>");
	pw.println("</div>");
	printFooter(pw);
	}
	}