package org.restafarian.core.filters;

 import java.io.IOException;

 import javax.servlet.Filter;

 import javax.servlet.FilterChain;

 import javax.servlet.FilterConfig;

 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.configuration.Configuration;

 import org.apache.commons.configuration.ConfigurationException;

 import org.apache.commons.configuration.ConfigurationFactory;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 /**

  * <p>This is the base class for all servlet filters.</p>

  */

 public abstract class FilterBase implements Filter {

         protected ServletContext context = null;

         protected Log log = LogFactory.getLog(getClass());

         /**

          * <p>Filter "do filter" method.</p>

          *

          * @param req the servlet request object

          * @param res the servlet response object

          * @param chain the filter chain object

          * @throws ServletException

          * @throws IOException

          */

         public abstract void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws ServletException, IOException;

         /**

          * <p>Sends the HTTP error code and message, and logs the code and message if enabled.</p>

          *

          * @param req the <code>HttpServletRequest</code> object

          * @param res the <code>HttpServletResponse</code> object

          * @param errorCode the error code to send

          * @param errorMessage the error message to send

          */

         protected void sendError(HttpServletRequest req, HttpServletResponse res, int errorCode, String errorMessage) throws IOException {

                 // log error, if enabled

                 if (log.isDebugEnabled()) {

                         log.debug("Sending error " + errorCode + "; message=" + errorMessage);

                 }

                 // send error

                 res.sendError(errorCode, errorMessage);

         }

         /**

          * <p>Filter init method.</p>

          *

          * @param config the FilterConfig object

          */

         public void init(FilterConfig config) {

                 log.info("Initializing " + getClass().getName());

                 // save servle context for later use

                 context = config.getServletContext();

                 // look for configuration source file name

                 String cfgsrc = config.getInitParameter("configFileName");

                 if (cfgsrc != null && cfgsrc.length() > 0) {

                         // configuration source file name found

                         log.info("Configuration source file specified: " + cfgsrc);

                         // build configuration factory using source file name

                         ConfigurationFactory factory = new ConfigurationFactory(cfgsrc);

                         try {

                                 // get configuration from factory

                                 Configuration configuration = factory.getConfiguration();

                                 // store configuration in servlet context for future use

                                 context.setAttribute("configuration", configuration);

                                 // log success

                                 log.info("Configuration loaded using bootstrap file " + cfgsrc);

                         } catch (ConfigurationException e) {

                                 // log the error

                                 log.error("Exception encountered when attempting to obtain current configuration: " + e, e);

                         }

                 }

         }

         /**

          * <p>Filter destroy method.</p>

          */

         public void destroy() {

         }

 }