1 /*
2 * $Id: DefaultAttributeResolver.java 836174 2009-11-14 13:40:31Z 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
22 package org.apache.tiles.template;
23
24 import org.apache.tiles.Attribute;
25 import org.apache.tiles.AttributeContext;
26 import org.apache.tiles.Expression;
27 import org.apache.tiles.TilesContainer;
28 import org.apache.tiles.request.Request;
29
30 /**
31 * The default implementation of AttributeResolver.
32 *
33 * @version $Rev: 836174 $ $Date: 2009-11-15 00:40:31 +1100 (Sun, 15 Nov 2009) $
34 * @since 2.2.0
35 */
36 public class DefaultAttributeResolver implements AttributeResolver {
37
38 /** {@inheritDoc} */
39 public Attribute computeAttribute(TilesContainer container, Attribute attribute,
40 String name, String role, boolean ignore,
41 Object defaultValue, String defaultValueRole, String defaultValueType, Request request) {
42 if (attribute == null) {
43 AttributeContext evaluatingContext = container
44 .getAttributeContext(request);
45 attribute = evaluatingContext.getAttribute(name);
46 if (attribute == null) {
47 attribute = computeDefaultAttribute(defaultValue,
48 defaultValueRole, defaultValueType);
49 if (attribute == null && !ignore) {
50 throw new NoSuchAttributeException("Attribute '" + name
51 + "' not found.");
52 }
53 }
54 }
55 if (attribute != null && role != null && !"".equals(role.trim())) {
56 attribute = new Attribute(attribute);
57 attribute.setRole(role);
58 }
59 return attribute;
60 }
61
62 /**
63 * Computes the default attribute.
64 *
65 * @param defaultValue The default value of the attribute.
66 * @param defaultValueRole The default role of tha attribute.
67 * @param defaultValueType The default type of the attribute.
68 * @return The default attribute.
69 */
70 private Attribute computeDefaultAttribute(Object defaultValue,
71 String defaultValueRole, String defaultValueType) {
72 Attribute attribute = null;
73 if (defaultValue != null) {
74 if (defaultValue instanceof Attribute) {
75 attribute = (Attribute) defaultValue;
76 } else if (defaultValue instanceof String) {
77 attribute = new Attribute(defaultValue, (Expression) null,
78 defaultValueRole, defaultValueType);
79 }
80 }
81 return attribute;
82 }
83 }