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1   /*
2    * $Id: AddAttributeModel.java 1305937 2012-03-27 18:15:15Z nlebas $
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  
22  package org.apache.tiles.template;
23  
24  import java.io.IOException;
25  import java.util.Deque;
26  
27  import org.apache.tiles.Attribute;
28  import org.apache.tiles.Expression;
29  import org.apache.tiles.ListAttribute;
30  import org.apache.tiles.autotag.core.runtime.ModelBody;
31  import org.apache.tiles.request.Request;
32  
33  /**
34   * <p>
35   * <strong>Add an element to the surrounding list. Equivalent to 'putAttribute',
36   * but for list element.</strong>
37   * </p>
38   *
39   * <p>
40   * Add an element to the surrounding list. This tag can only be used inside
41   * 'putListAttribute' or 'addListAttribute' tags. Value can come from a direct
42   * assignment (value="aValue")
43   * </p>
44   *
45   * @version $Rev: 1305937 $ $Date: 2012-03-28 05:15:15 +1100 (Wed, 28 Mar 2012) $
46   * @since 2.2.0
47   */
48  public class AddAttributeModel {
49  
50      /**
51       * Executes the operation.
52       * @param value The value of the attribute. Use this parameter, or
53       * expression, or body.
54       * @param expression The expression to calculate the value from. Use this
55       * parameter, or value, or body.
56       * @param role A comma-separated list of roles. If present, the attribute
57       * will be rendered only if the current user belongs to one of the roles.
58       * @param type The type (renderer) of the attribute.
59       * @param request The request.
60       * @param modelBody The body.
61       * @throws IOException If the body cannot be correctly evaluated.
62       * @since 2.2.0
63       */
64      public void execute(Object value, String expression, String role,
65              String type, Request request, ModelBody modelBody)
66              throws IOException {
67          Attribute attribute = new Attribute();
68          Deque<Object> composeStack = ComposeStackUtil.getComposeStack(request);
69          composeStack.push(attribute);
70          String body = modelBody.evaluateAsString();
71          attribute = (Attribute) composeStack.pop();
72          addAttributeToList(attribute, composeStack, value, expression, body,
73                  role, type);
74      }
75  
76      /**
77       * Adds the attribute to the containing list attribute.
78       *
79       * @param attribute The attribute to add to the list attribute.
80       * @param composeStack The composing stack.
81       * @param value The value of the attribute. Use this parameter, or
82       * expression, or body.
83       * @param expression The expression to calculate the value from. Use this
84       * parameter, or value, or body.
85       * @param body The body of the tag. Use this parameter, or value, or
86       * expression.
87       * @param role A comma-separated list of roles. If present, the attribute
88       * will be rendered only if the current user belongs to one of the roles.
89       * @param type The type (renderer) of the attribute.
90       * @since 2.2.0
91       */
92      private void addAttributeToList(Attribute attribute,
93              Deque<Object> composeStack, Object value, String expression,
94              String body, String role, String type) {
95          ListAttribute listAttribute = (ListAttribute) ComposeStackUtil
96                  .findAncestorWithClass(composeStack, ListAttribute.class);
97  
98          if (listAttribute == null) {
99              throw new NullPointerException("There is no ListAttribute in the stack");
100         }
101         if (value != null) {
102             attribute.setValue(value);
103         } else if (attribute.getValue() == null && body != null) {
104             attribute.setValue(body);
105         }
106         if (expression != null) {
107             attribute.setExpressionObject(Expression
108                     .createExpressionFromDescribedExpression(expression));
109         }
110         if (role != null) {
111             attribute.setRole(role);
112         }
113         if (type != null) {
114             attribute.setRenderer(type);
115         }
116         listAttribute.add(attribute);
117     }
118 }