/*

  * This software is licensed under the Apache License, Version 2.0

  * (the "License") agreement; 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 net.admin4j.ui.servlets;

 import java.io.ByteArrayInputStream;

 import java.io.ByteArrayOutputStream;

 import java.io.IOException;

 import java.io.OutputStreamWriter;

 import java.util.Enumeration;

 import java.util.Map;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import net.admin4j.deps.commons.io.IOUtils;

 import net.admin4j.util.Admin4jRuntimeException;

 import net.admin4j.util.FreemarkerUtils;

 import freemarker.template.Template;

 /**

  * Base class for Administrative display servlets.

  * @author D. Ashmore

  * @since 1.0

  */

 public abstract class AdminDisplayServlet extends Admin4JServlet {

     public static final String ADMIN4J_SESSION_VARIABLE_PREFIX = "Admin4j";

     private static final long serialVersionUID = -7324380011384838424L;

     /**

      * Will generate Freemarker template results and write it to the output stream.

      * @param response

      * @param templateName

      * @param variableMap

      * @throws IOException

      */

     protected void displayFreeMarkerPage(HttpServletRequest request, 

             HttpServletResponse response, String templateName,

             Map<String, Object> variableMap) throws IOException {

                 response.setContentType("text/html");

                 displayFreeMarkerResponse(request, response, templateName, variableMap);

             }

     @SuppressWarnings("unchecked")

     protected void displayFreeMarkerResponse(HttpServletRequest request, 

             HttpServletResponse response,

             String templateName, Map<String, Object> variableMap)

             throws IOException {

         Enumeration<String> attrNameEnum = request.getSession().getAttributeNames();

         String attrName;

         while (attrNameEnum.hasMoreElements()) {

             attrName = attrNameEnum.nextElement();

             if (attrName != null && attrName.startsWith(ADMIN4J_SESSION_VARIABLE_PREFIX)) {

                 variableMap.put("Session" +attrName, request.getSession().getAttribute(attrName));

             }

         }

         variableMap.put("RequestAdmin4jCurrentUri", request.getRequestURI());

         Template temp = FreemarkerUtils.createConfiguredTemplate(this.getClass(), templateName);

         ByteArrayOutputStream outStream = new ByteArrayOutputStream();

         try {

             temp.process(variableMap, new OutputStreamWriter(outStream));

             response.setContentLength(outStream.size());

             IOUtils.copy(new ByteArrayInputStream(outStream.toByteArray()), response.getOutputStream());

             response.getOutputStream().flush();

             response.getOutputStream().close();

         }

         catch (Exception e) {

             throw new Admin4jRuntimeException(e);

         }

     }

     /* (non-Javadoc)

      * @see net.admin4j.ui.servlets.Admin4JServlet#hasDisplay()

      */

     @Override

     public boolean hasDisplay() {

         return true;

     }

     public abstract String getServletLabel();

 }