package org.trails.exception;

 import java.io.IOException;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.apache.tapestry.IPage;

 import org.apache.tapestry.IRequestCycle;

 import org.apache.tapestry.error.ExceptionPresenterImpl;

 import org.trails.exception.TrailsRuntimeException;

 import org.trails.page.PageResolver;

 import org.trails.page.PageType;

 /* kaosko 2007-06-18:

  * I would have really liked to implement the exception presenter only as a handler in pipeline

  * (as described at http://mail-archives.apache.org/mod_mbox/tapestry-dev/200606.mbox/%3C000a01c6906b$6ba3b8b0$6601a8c0@CARMANI9300%3E)

  * It required some changed in Hivemind core that were already implemented in Hivemind 1.1.2 which was never

  * released even though it apparently came very close. I've inquired about the status of 1.1.2 on Hivemind list

  */

 public class ApplicationExceptionPresenterImpl extends ExceptionPresenterImpl {

         private static final Log log = LogFactory.getLog(ApplicationExceptionPresenterImpl.class);

         private PageResolver pageResolver;

         public void presentException(IRequestCycle cycle, Throwable throwable) {

                 if (throwable.getCause() == null || !(throwable.getCause() instanceof TrailsRuntimeException)) {

                         super.presentException(cycle, throwable);

                         return;

                 }

                 TrailsRuntimeException trailsRuntimeException = (TrailsRuntimeException)throwable.getCause();

                 if (log.isWarnEnabled())

                 {

                         if (trailsRuntimeException.getEntityType() == null)

                         {

                                 log.warn("Trails specific exception happened while handling unknown entity, caused by: " + throwable.getCause().getMessage());

                         } else

                         {

                                 log.warn("Trails specific exception happened while handling entity type " + trailsRuntimeException.getEntityType().getName() + ", caused by: " + throwable.getCause().getMessage());

                         }

                 }

                 log.debug("The problem was caused by: ", throwable.getCause());

                 IPage page = pageResolver.resolvePage(cycle, trailsRuntimeException.getEntityType(), PageType.EXCEPTION);

                 cycle.activate(page);

                 try {

                         cycle.getResponseBuilder().renderResponse(cycle);

                 } catch (IOException e) {

                         log.error("Couldn't render a Trails specific error page because of : ", e);

                         super.presentException(cycle, throwable);

                 }

         }

         public void setPageResolver(PageResolver pageResolver) {

                 this.pageResolver = pageResolver;

         }

 }