Project Tiles has retired. For details please refer to its Attic page.
BasicAttributeEvaluatorFactory xref
View Javadoc

1   /*
2    * $Id: BasicAttributeEvaluatorFactory.java 788032 2009-06-24 14:08:32Z 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.evaluator;
23  
24  import java.util.HashMap;
25  import java.util.Map;
26  
27  import org.apache.tiles.Attribute;
28  import org.apache.tiles.Expression;
29  
30  /**
31   * Basic implementation of {@link AttributeEvaluatorFactory}. It supports a
32   * default attribute evaluator, in case the language is not recognized.
33   *
34   * @version $Rev: 788032 $ $Date: 2009-06-25 00:08:32 +1000 (Thu, 25 Jun 2009) $
35   * @since 2.2.0
36   */
37  public class BasicAttributeEvaluatorFactory implements
38          AttributeEvaluatorFactory {
39  
40      /**
41       * The default evaluator to return if it is not found in the map of known
42       * languages.
43       */
44      private AttributeEvaluator defaultEvaluator;
45  
46      /**
47       * Maps names of expression languages to their attribute evaluator.
48       *
49       * @since 2.2.0
50       */
51      private Map<String, AttributeEvaluator> language2evaluator;
52  
53      /**
54       * Constructor.
55       *
56       * @param defaultEvaluator The default evaluator to return if it is not
57       * found in the map of known languages.
58       * @since 2.2.0
59       */
60      public BasicAttributeEvaluatorFactory(AttributeEvaluator defaultEvaluator) {
61          this.defaultEvaluator = defaultEvaluator;
62          language2evaluator = new HashMap<String, AttributeEvaluator>();
63      }
64  
65      /**
66       * Registers a known expression language with its attribute evaluator.
67       *
68       * @param language The name of the expression language.
69       * @param evaluator The associated attribute evaluator.
70       * @since 2.2.0
71       */
72      public void registerAttributeEvaluator(String language, AttributeEvaluator evaluator) {
73          language2evaluator.put(language, evaluator);
74      }
75  
76      /** {@inheritDoc} */
77      public AttributeEvaluator getAttributeEvaluator(String language) {
78          AttributeEvaluator retValue = language2evaluator.get(language);
79          if (retValue == null) {
80              retValue = defaultEvaluator;
81          }
82          return retValue;
83      }
84  
85      /** {@inheritDoc} */
86      public AttributeEvaluator getAttributeEvaluator(Attribute attribute) {
87          Expression expression = attribute.getExpressionObject();
88          if (expression != null) {
89              return getAttributeEvaluator(expression.getLanguage());
90          }
91          return defaultEvaluator;
92      }
93  }