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1   /*
2    * $Id: TemplateAttributeRenderer.java 821299 2009-10-03 12:15:05Z apetrelli $
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   * http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  package org.apache.tiles.renderer.impl;
22  
23  import java.io.IOException;
24  
25  import org.apache.tiles.Attribute;
26  import org.apache.tiles.context.TilesRequestContext;
27  import org.apache.tiles.impl.InvalidTemplateException;
28  
29  /***
30   * Renders an attribute that contains a reference to a template.
31   *
32   * @version $Rev: 821299 $ $Date: 2009-10-03 14:15:05 +0200 (sab, 03 ott 2009) $
33   * @since 2.1.0
34   */
35  public class TemplateAttributeRenderer extends AbstractTypeDetectingAttributeRenderer {
36  
37      /*** {@inheritDoc} */
38      @Override
39      public void write(Object value, Attribute attribute,
40              TilesRequestContext request)
41              throws IOException {
42          if (value != null) {
43              if (value instanceof String) {
44                  request.dispatch(value.toString());
45              } else {
46                  throw new InvalidTemplateException(
47                          "Cannot render a template that is not a string: "
48                                  + value.toString());
49              }
50          } else {
51              throw new InvalidTemplateException("Cannot render a null template");
52          }
53      }
54  
55      /*** {@inheritDoc} */
56      public boolean isRenderable(Object value, Attribute attribute,
57              TilesRequestContext request) {
58          if (value instanceof String) {
59              return ((String) value).startsWith("/");
60          }
61          return false;
62      }
63  }