/*

  * $Id: AbstractDefaultToStringRenderable.java 791161 2009-07-04 18:53:36Z apetrelli $

  *

  * 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.tiles.velocity.template;

 import java.io.IOException;

 import java.io.StringWriter;

 import java.util.Map;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import org.apache.tiles.velocity.TilesVelocityException;

 import org.apache.velocity.context.Context;

 import org.apache.velocity.exception.MethodInvocationException;

 import org.apache.velocity.exception.ParseErrorException;

 import org.apache.velocity.exception.ResourceNotFoundException;

 import org.apache.velocity.runtime.Renderable;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 /**

  * Renderable that provides a default implementation of {@link Renderable#toString()}

  * and allows access to parameters and context objects.

  *

  * @version $Rev: 791161 $ $Date: 2009-07-05 04:53:36 +1000 (Sun, 05 Jul 2009) $

  * @since 2.2.0

  */

 public abstract class AbstractDefaultToStringRenderable implements Renderable {

     /**

      * The Velocity context.

      *

      * @since 2.2.0

      */

     protected final Context velocityContext;

     /**

      * The parameters used in the current tool call.

      *

      * @since 2.2.0

      */

     protected final Map<String, Object> params;

     /**

      * The HTTP response.

      *

      * @since 2.2.0

      */

     protected final HttpServletResponse response;

     /**

      * The HTTP request.

      *

      * @since 2.2.0

      */

     protected final HttpServletRequest request;

     /**

      * The logging object.

      */

     private final Logger log = LoggerFactory.getLogger(getClass());

     /**

      * Constructor.

      *

      * @param velocityContext The Velocity context.

      * @param params The parameters used in the current tool call.

      * @param response The HTTP response.

      * @param request The HTTP request.

      * @since 2.2.0

      */

     public AbstractDefaultToStringRenderable(Context velocityContext,

             Map<String, Object> params, HttpServletResponse response,

             HttpServletRequest request) {

         this.velocityContext = velocityContext;

         this.params = params;

         this.response = response;

         this.request = request;

     }

     /** {@inheritDoc} */

     @Override

     public String toString() {

         StringWriter writer = new StringWriter();

         try {

             render(null, writer);

         } catch (MethodInvocationException e) {

             throw new TilesVelocityException("Cannot invoke method when rendering", e);

         } catch (ParseErrorException e) {

             throw new TilesVelocityException("Cannot parse when rendering", e);

         } catch (ResourceNotFoundException e) {

             throw new TilesVelocityException("Cannot find resource when rendering", e);

         } catch (IOException e) {

             throw new TilesVelocityException("I/O exception when rendering", e);

         } finally {

             try {

                 writer.close();

             } catch (IOException e) {

                 log.error("Error when closing a StringWriter, the impossible happened!", e);

             }

         }

         return writer.toString();

     }

 }