/*
    * $Id: VelocityStyleTilesTool.java 1058140 2011-01-12 13:49:44Z 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.Writer;
  
  import javax.servlet.ServletContext;
  
  import org.apache.tiles.Attribute;
  import org.apache.tiles.AttributeContext;
  import org.apache.tiles.TilesContainer;
  import org.apache.tiles.access.TilesAccess;
  import org.apache.tiles.request.Request;
  import org.apache.tiles.request.servlet.ServletUtil;
  import org.apache.tiles.request.velocity.VelocityRequest;
  import org.apache.velocity.context.InternalContextAdapter;
  import org.apache.velocity.runtime.Renderable;
  
  /**
   * Tiles Tool to be used "the classic way".
   *
   * @version $Rev: 1058140 $ $Date: 2011-01-13 00:49:44 +1100 (Thu, 13 Jan 2011) $
   * @since 2.2.0
   */
  public class VelocityStyleTilesTool extends ContextHolder {
  
      /**
       * Returns an attribute.
       *
       * @param key The name of the attribute to get.
       * @return The Attribute.
       * @since 2.2.0
       */
      public Attribute get(String key) {
          Request velocityRequest = createVelocityRequest(getServletContext(),
                  null);
          TilesContainer container = TilesAccess.getCurrentContainer(velocityRequest);
          AttributeContext attributeContext = container
                  .getAttributeContext(velocityRequest);
          Attribute attribute = attributeContext.getAttribute(key);
          return attribute;
      }
  
      /**
       * Creates a new empty attribute.
       *
       * @return The created attribute.
       * @since 2.2.0
       */
      public Attribute createAttribute() {
          return new Attribute();
      }
  
      /**
       * Creates an attribute that is a copy of the one passed as a parameter.
       *
       * @param attribute The attribute to copy.
       * @return The copied attribute.
       * @since 2.2.0
       */
      public Attribute clone(Attribute attribute) {
          return new Attribute(attribute);
      }
  
      /**
       * Creates an attribute that represents a template.
       *
       * @param template The template.
       * @return The attribute.
       * @since 2.2.0
       */
      public Attribute createTemplateAttribute(String template) {
          return Attribute.createTemplateAttribute(template);
      }
  
      /**
       * Renders an attribute.
       *
       * @param attribute The attribute to render.
      * @return The renderable object, ready to be rendered.
      * @since 2.2.0
      */
     public Renderable render(final Attribute attribute) {
         return new AbstractDefaultToStringRenderable(getVelocityContext(),
                 null, getResponse(), getRequest()) {
 
             public boolean render(InternalContextAdapter context, Writer writer)
                     throws IOException {
                 Request velocityRequest = createVelocityRequest(
                         getServletContext(), writer);
                 TilesContainer container = TilesAccess
                         .getCurrentContainer(velocityRequest);
                 container.render(attribute, velocityRequest);
                 return true;
             }
 
         };
     }
 
     /**
      * Renders a definition. It can be used in conjunction with
      * {@link #startAttributeContext()} and {@link #endAttributeContext()} to
      * customize appearance.
      *
      * @param definitionName The name of the definition to render.
      * @return The renderable that renders the definition.
      * @since 2.2.0
      */
     public Renderable renderDefinition(final String definitionName) {
         return new AbstractDefaultToStringRenderable(getVelocityContext(),
                 null, getResponse(), getRequest()) {
 
             public boolean render(InternalContextAdapter context, Writer writer) {
                 Request velocityRequest = createVelocityRequest(
                         getServletContext(), writer);
                 TilesContainer container = TilesAccess
                         .getCurrentContainer(velocityRequest);
                 container.render(definitionName, velocityRequest);
                 return true;
             }
 
         };
     }
 
     /**
      * Renders the current attribute context. It can be used in conjunction with
      * {@link #startAttributeContext()} and {@link #endAttributeContext()} to
      * customize appearance.
      *
      * @return The renderable that renders the current attribute context.
      * @since 2.2.0
      */
     public Renderable renderAttributeContext() {
         return new AbstractDefaultToStringRenderable(getVelocityContext(),
                 null, getResponse(), getRequest()) {
 
             public boolean render(InternalContextAdapter context, Writer writer) {
                 Request velocityRequest = createVelocityRequest(
                         getServletContext(), writer);
                 TilesContainer container = TilesAccess
                         .getCurrentContainer(velocityRequest);
                 container.renderContext(velocityRequest);
                 return true;
             }
 
         };
     }
 
     /**
      * Starts the attribute context. Remember to call
      * {@link #endAttributeContext()} when finished!
      *
      * @return The started attribute context, ready to be customized.
      * @since 2.2.0
      */
     public AttributeContext startAttributeContext() {
         Request velocityRequest = createVelocityRequest(
                 getServletContext(), null);
         TilesContainer container = TilesAccess
                 .getCurrentContainer(velocityRequest);
         return container.startContext(velocityRequest);
     }
 
     /**
      * Ends the current attribute context. To be called after
      * {@link #startAttributeContext()}.
      *
      * @return The tool itself.
      * @since 2.2.0
      */
     public VelocityStyleTilesTool endAttributeContext() {
         Request velocityRequest = createVelocityRequest(getServletContext(),
                 null);
         TilesContainer container = TilesAccess
                 .getCurrentContainer(velocityRequest);
         container.endContext(velocityRequest);
         return this;
     }
 
     /**
      * Returns the current attribute context.
      *
      * @return The current attribute context.
      * @since 2.2.0
      */
     public AttributeContext getAttributeContext() {
         Request velocityRequest = createVelocityRequest(
                 getServletContext(), null);
         TilesContainer container = TilesAccess
                 .getCurrentContainer(velocityRequest);
         return container.getAttributeContext(velocityRequest);
     }
 
     /**
      * Sets the current container for the current request.
      *
      * @param containerKey The key of the container to set as "current" for the current request.
      * @return The tool itself.
      * @since 2.2.0
      */
     public VelocityStyleTilesTool setCurrentContainer(String containerKey) {
         Request velocityRequest = createVelocityRequest(
                 getServletContext(), null);
         TilesAccess.setCurrentContainer(velocityRequest, containerKey);
         return this;
     }
 
     /** {@inheritDoc} */
     @Override
     public String toString() {
         return "";
     }
 
     /**
      * Creates a Velocity request.
      *
      * @param servletContext The servlet context.
      * @param writer The writer.
      * @return The created request.
      */
     protected Request createVelocityRequest(
             ServletContext servletContext, Writer writer) {
         return VelocityRequest.createVelocityRequest(ServletUtil
                 .getApplicationContext(servletContext), getRequest(),
                 getResponse(), getVelocityContext(), writer);
     }
 }