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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    * 
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software 
12   * distributed under the License is distributed on an "AS IS" BASIS, 
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
14   * See the License for the specific language governing permissions and 
15   * limitations under the License.
16   */
17  
18  package org.apache.jdo.impl.model.jdo.caching;
19  
20  import org.apache.jdo.model.java.JavaType;
21  import org.apache.jdo.model.jdo.JDORelationship;
22  import org.apache.jdo.impl.model.jdo.JDOArrayImplDynamic;
23  
24  /***
25   * An instance of this class represents the JDO relationship metadata 
26   * of a array relationship field. This caching implementation
27   * caches any calulated value to avoid re-calculating it if it is
28   * requested again. 
29   *
30   * @author Michael Bouschen
31   * @since 1.1
32   * @version 2.0
33   */
34  public class JDOArrayImplCaching extends JDOArrayImplDynamic {
35      
36      /*** Type of the array element. */
37      private transient JavaType elementType;
38      
39      /*** 
40       * Get the mappedBy relationship. If there is no mappedBy relationship
41       * set, the method checks the mappedBy name as specified in the declaring
42       * field and resolves the relationship. The method returns
43       * <code>null</code> if there is no mappedBy relationship set and there
44       * is no mappedBy name specified on the declaring field.
45       * @return the mappedBy relationship if available; <code>null</code>
46       * otherwise.
47       */
48      public JDORelationship getMappedBy() {
49          if (mappedBy == null) {
50              mappedBy = super.getMappedBy();
51          }
52          return mappedBy;
53      }
54  
55      /***
56       * Get the inverse JDORelationship in the case of a two-way relationship.
57       * @return the inverse relationship
58       */
59      public JDORelationship getInverseRelationship() {
60          if (inverse == null) {
61              inverse = super.getInverseRelationship();
62          }
63          return inverse;
64      }
65  
66      /***
67       * Determines whether the values of the elements should be stored 
68       * if possible as part of the instance instead of as their own instances 
69       * in the datastore.
70       * @return <code>true</code> if the elements should be stored as part of 
71       * the instance; <code>false</code> otherwise
72       */
73      public boolean isEmbeddedElement() {
74          if (embeddedElement == null) {
75              embeddedElement = 
76                  super.isEmbeddedElement() ? Boolean.TRUE : Boolean.FALSE;
77          }
78          return embeddedElement.booleanValue();
79      }
80      
81      /*** 
82       * Get the type representation of the array component type. 
83       * @return the array component type
84       */
85      public JavaType getElementType() {
86          if (elementType == null) {
87              elementType = super.getElementType();
88          }
89          return elementType;
90      }
91  
92  }
93