NavField


1   
2   /*
3    * Copyright (c) 1998 - 2005 Versant Corporation
4    * All rights reserved. This program and the accompanying materials
5    * are made available under the terms of the Eclipse Public License v1.0
6    * which accompanies this distribution, and is available at
7    * http://www.eclipse.org/legal/epl-v10.html
8    *
9    * Contributors:
10   * Versant Corporation - initial API and implementation
11   */
12  package com.versant.core.ejb.query;
13  
14  import com.versant.core.metadata.FieldMetaData;
15  import com.versant.core.metadata.ClassMetaData;
16  
17  /**
18   * Navigation through a field.
19   */
20  public class NavField extends NavBase {
21  
22      private FieldMetaData fmd;  // the field being navigated
23      private boolean outer;      // navigate with outer join semantics
24      private boolean fetch;      // is this navigation for a fetch?
25  
26      private NavBase parent; // our parent
27      private NavField next;  // our next sibling
28  
29      /**
30       * This will append us to our parents list of children.
31       */
32      public NavField(FieldMetaData fmd, NavBase parent, boolean outer,
33              boolean fetch) {
34          this.fmd = fmd;
35          this.outer = outer;
36          this.fetch = fetch;
37          setParent(parent);
38      }
39  
40      /**
41       * Remove us from our current parent (if any) and add us to np.
42       */
43      public void setParent(NavBase np) {
44          if (parent == np) {
45              return;
46          }
47          if (parent != null) {
48              NavField p = null;
49              for (NavField i = parent.children; i != this; i = i.next);
50              if (p == null) {
51                  parent.children = next;
52              } else {
53                  p.next = next;
54              }
55              next = null;
56          }
57          parent = np;
58          if (parent != null) {
59              if (parent.children == null) {
60                  parent.children = this;
61              } else {
62                  NavField i;
63                  for (i = parent.children; i.next != null; i = i.next);
64                  i.next = this;
65              }
66          }
67      }
68  
69      /**
70       * Get the field being navigated.
71       */
72      public FieldMetaData getFmd() {
73          return fmd;
74      }
75  
76      public NavRoot getRoot() {
77          return parent == null ? null : parent.getRoot();
78      }
79  
80      public NavBase getParent() {
81          return parent;
82      }
83  
84      public NavField getNext() {
85          return next;
86      }
87  
88      public boolean isOuter() {
89          return outer;
90      }
91  
92      public boolean isFetch() {
93          return fetch;
94      }
95  
96      public ClassMetaData getNavClassMetaData() {
97          return fmd.getRefOrValueClassMetaData();
98      }
99  
100     public String   toString() {
101         StringBuffer   s = new StringBuffer  ();
102         s.append(fmd.name);
103         childrenToString(s);
104         return s.toString();
105     }
106 
107 }
108 
109
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