cvs commit: jakarta-velocity/src/java/org/apache/velocity/servlet VelocityServlet.java

[da...@locus.apache.org]

daveb       00/08/27 17:45:43

  Added:       src/java/org/apache/velocity/servlet VelocityServlet.java
  Log:
  Initial add.
  
  Revision  Changes    Path
  1.1                  jakarta-velocity/src/java/org/apache/velocity/servlet/VelocityServlet.java
  
  Index: VelocityServlet.java
  ===================================================================
  package org.apache.velocity.servlet;
  
  /*
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 2000 The Apache Software Foundation.  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.
   *
   * 3. The end-user documentation included with the redistribution, if
   *    any, must include the following acknowlegement:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowlegement may appear in the software itself,
   *    if and wherever such third-party acknowlegements normally appear.
   *
   * 4. The names "The Jakarta Project", "Velocity", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache"
   *    nor may "Apache" appear in their names without prior written
   *    permission of the Apache Group.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
   * ITS 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   */
  
  import java.io.*;
  import java.util.*;
  
  import javax.servlet.*;
  import javax.servlet.http.*;
  
  import org.apache.velocity.*;
  import org.apache.velocity.runtime.*;
  
  /**
   * Base class to use Velocity with Servlets.
   * Simply extend this class, override the handleRequest method
   * and add your data to the context. Then call getTemplate("mytemplate.wm")
   * 
   * @author Dave Bryson
   * $Revision: 1.1 $
   */
  public abstract class VelocityServlet extends HttpServlet
  {
      private TemplateLoader loader;
  
      /** 
       * Init the loader
       * @param ServletConfig
       */
      public void init( ServletConfig config )
       throws ServletException
      {
          super.init( config );
          
          String file = config.getInitParameter("properties");
           try
           {
               Configuration.setPropertiesFile(file);
               loader = TemplateFactory.getLoader();
           }
           catch( Exception e1 )
           {
               throw new ServletException( "Error configuring the loader: " + e1);
           }
          
      }
      
      /**
       * Handles GET
       */
      public void doGet( HttpServletRequest request, HttpServletResponse response )
          throws ServletException, IOException
      {
          doRequest(request, response);
      }
  
      /**
       * Handle a POST
       */
      public void doPost( HttpServletRequest request, HttpServletResponse response )
          throws ServletException, IOException
      {
          doRequest(request, response);
      }
      
      /**
       * Process the request.
       */
      private void doRequest(HttpServletRequest request, HttpServletResponse response )
           throws ServletException, IOException
      {
          Context ctx = new Context();
          Template t = handleRequest(ctx);
          
          if ( t == null )
          {
              error( response, "Cannot find template!");
              return;
          }
          
          t.setContext(ctx);
          writeTemplate( response, t); 
      }
      
      /**
       * @return the requested template
       */
      public Template getTemplate( String name )
       throws Exception
      {
          return loader.getTemplate(name);
      }
      
      /**
       * Override the method to add your information to the
       * context and call the getTemplate method.
       * @param Context 
       * @return Template
       */
      public abstract Template handleRequest( Context ctx );
   
      /**
       * Write the template out
       */
      private void writeTemplate( HttpServletResponse response,  Template template )
          throws ServletException, IOException
      {
          response.setContentType("text/html");
          PrintWriter out = response.getWriter();
          try
          {
              template.parse();
              out.println( template.toString() );
          }
          catch( Exception e )
          {
              error( response, e.toString() );
          }
      }
  
      /**
       * Send an error message
       */
      private void error( HttpServletResponse response, String message )
          throws ServletException, IOException
      {
          StringBuffer html = new StringBuffer();
          html.append("<html>");
          html.append("<body bgcolor=\"#ffffff\">");
          html.append("<h2>Error processing the template</h2>");
          html.append(message);
          html.append("</body>");
          html.append("</html>");
          
          response.setContentType("text/html");
          PrintWriter out = response.getWriter();
          
          out.println( html.toString() );
      }
  }