/*
    * $Id: GetAsStringModel.java 797765 2009-07-25 13:20:26Z 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.template;
  
  import java.io.IOException;
  import java.io.Writer;
  
  import org.apache.tiles.ArrayStack;
  import org.apache.tiles.Attribute;
  import org.apache.tiles.TilesContainer;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /***
   * <p>
   * <strong> Render the value of the specified template attribute to the current
   * Writer</strong>
   * </p>
   *
   * <p>
   * Retrieve the value of the specified template attribute property, and render
   * it to the current Writer as a String. The usual toString() conversions is
   * applied on found value.
   * </p>
   *
   * @version $Rev: 797765 $ $Date: 2009-07-25 15:20:26 +0200 (sab, 25 lug 2009) $
   * @since 2.2.0
   */
  public class GetAsStringModel {
  
      /***
       * The logging object.
       */
      private Logger log = LoggerFactory.getLogger(getClass());
  
      /***
       * The attribute resolver to use.
       */
      private AttributeResolver attributeResolver;
  
      /***
       * Constructor.
       *
       * @param attributeResolver The attribute resolver to use.
       * @since 2.2.0
       */
      public GetAsStringModel(AttributeResolver attributeResolver) {
          this.attributeResolver = attributeResolver;
      }
  
      /***
       * Starts the operation.
       *
       * @param composeStack The compose stack,
       * @param container The Tiles container to use.
       * @param ignore If <code>true</code>, if an exception happens during
       * rendering, of if the attribute is null, the problem will be ignored.
       * @param preparer The preparer to invoke before rendering the attribute.
       * @param role A comma-separated list of roles. If present, the attribute
       * will be rendered only if the current user belongs to one of the roles.
       * @param defaultValue The default value of the attribute. To use only if
       * the attribute was not computed.
       * @param defaultValueRole The default comma-separated list of roles. To use
       * only if the attribute was not computed.
       * @param defaultValueType The default type of the attribute. To use only if
       * the attribute was not computed.
       * @param name The name of the attribute.
       * @param value The attribute to use immediately, if not null.
       * @param requestItems The request objects.
       * @since 2.2.0
       */
      public void start(ArrayStack<Object> composeStack, TilesContainer container,
              boolean ignore, String preparer, String role, Object defaultValue,
              String defaultValueRole, String defaultValueType, String name,
              Attribute value, Object... requestItems) {
          Attribute attribute = resolveAttribute(container, ignore, preparer,
                  role, defaultValue, defaultValueRole, defaultValueType, name,
                  value, requestItems);
          composeStack.push(attribute);
      }
 
     /***
      * Ends the operation.
      *
      * @param composeStack The compose stack,
      * @param container The Tiles container to use.
      * @param writer The writer into which the attribute will be written.
      * @param ignore If <code>true</code>, if an exception happens during
      * rendering, of if the attribute is null, the problem will be ignored.
      * @param requestItems The request objects.
      * @throws IOException If an I/O error happens during rendering.
      */
     public void end(ArrayStack<Object> composeStack, TilesContainer container,
             Writer writer, boolean ignore, Object... requestItems)
             throws IOException {
         Attribute attribute = (Attribute) composeStack.pop();
         renderAttribute(attribute, container, writer, ignore, requestItems);
     }
 
     /***
      * Executes the operation.
      *
      * @param container The Tiles container to use.
      * @param writer The writer into which the attribute will be written.
      * @param ignore If <code>true</code>, if an exception happens during
      * rendering, of if the attribute is null, the problem will be ignored.
      * @param preparer The preparer to invoke before rendering the attribute.
      * @param role A comma-separated list of roles. If present, the attribute
      * will be rendered only if the current user belongs to one of the roles.
      * @param defaultValue The default value of the attribute. To use only if
      * the attribute was not computed.
      * @param defaultValueRole The default comma-separated list of roles. To use
      * only if the attribute was not computed.
      * @param defaultValueType The default type of the attribute. To use only if
      * the attribute was not computed.
      * @param name The name of the attribute.
      * @param value The attribute to use immediately, if not null.
      * @param requestItems The request objects.
      * @throws IOException If an I/O error happens during rendering.
      * @since 2.2.0
      */
     public void execute(TilesContainer container, Writer writer,
             boolean ignore, String preparer, String role, Object defaultValue,
             String defaultValueRole, String defaultValueType, String name,
             Attribute value, Object... requestItems) throws IOException {
         Attribute attribute = resolveAttribute(container, ignore, preparer,
                 role, defaultValue, defaultValueRole, defaultValueType, name,
                 value, requestItems);
         renderAttribute(attribute, container, writer, ignore, requestItems);
     }
 
     /***
      * Resolves the attribute. and starts the context.
      *
      * @param container The Tiles container to use.
      * @param ignore If <code>true</code>, if an exception happens during
      * rendering, of if the attribute is null, the problem will be ignored.
      * @param preparer The preparer to invoke before rendering the attribute.
      * @param role A comma-separated list of roles. If present, the attribute
      * will be rendered only if the current user belongs to one of the roles.
      * @param defaultValue The default value of the attribute. To use only if
      * the attribute was not computed.
      * @param defaultValueRole The default comma-separated list of roles. To use
      * only if the attribute was not computed.
      * @param defaultValueType The default type of the attribute. To use only if
      * the attribute was not computed.
      * @param name The name of the attribute.
      * @param value The attribute to use immediately, if not null.
      * @param requestItems The request objects.
      * @return The resolved attribute.
      */
     private Attribute resolveAttribute(TilesContainer container,
             boolean ignore, String preparer, String role, Object defaultValue,
             String defaultValueRole, String defaultValueType, String name,
             Attribute value, Object... requestItems) {
         if (preparer != null) {
             container.prepare(preparer, requestItems);
         }
         Attribute attribute = attributeResolver.computeAttribute(container,
                 value, name, role, ignore, defaultValue, defaultValueRole,
                 defaultValueType, requestItems);
         container.startContext(requestItems);
         return attribute;
     }
 
     /***
      * Renders the attribute as a string.
      *
      * @param attribute The attribute to use, previously resolved.
      * @param container The Tiles container to use.
      * @param writer The writer into which the attribute will be written.
      * @param ignore If <code>true</code>, if an exception happens during
      * rendering, of if the attribute is null, the problem will be ignored.
      * @param requestItems The request objects.
      * @throws IOException If an I/O error happens during rendering.
      */
     private void renderAttribute(Attribute attribute, TilesContainer container,
             Writer writer, boolean ignore, Object... requestItems)
             throws IOException {
         if (attribute == null && ignore) {
             return;
         }
         try {
             writer.write(attribute.getValue().toString());
         } catch (IOException e) {
             if (!ignore) {
                 throw e;
             } else if (log.isDebugEnabled()) {
                 log.debug("Ignoring exception", e);
             }
         } catch (RuntimeException e) {
             if (!ignore) {
                 throw e;
             } else if (log.isDebugEnabled()) {
                 log.debug("Ignoring exception", e);
             }
         } finally {
             container.endContext(requestItems);
         }
     }
 }