PersistenceElement


1   /*
2    * The contents of this file are subject to the terms 
3    * of the Common Development and Distribution License 
4    * (the License).  You may not use this file except in
5    * compliance with the License.
6    * 
7    * You can obtain a copy of the license at 
8    * https://glassfish.dev.java.net/public/CDDLv1.0.html or
9    * glassfish/bootstrap/legal/CDDLv1.0.txt.
10   * See the License for the specific language governing 
11   * permissions and limitations under the License.
12   * 
13   * When distributing Covered Code, include this CDDL 
14   * Header Notice in each file and include the License file 
15   * at glassfish/bootstrap/legal/CDDLv1.0.txt.  
16   * If applicable, add the following below the CDDL Header, 
17   * with the fields enclosed by brackets [] replaced by
18   * you own identifying information: 
19   * "Portions Copyrighted [year] [name of copyright owner]"
20   * 
21   * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
22   */
23  
24  /*
25   * PersistenceElement.java
26   *
27   * Created on February 28, 2000, 3:37 PM
28   */
29  
30  package com.sun.jdo.api.persistence.model.jdo;
31  
32  import java.util.ResourceBundle  ;
33  import java.beans.PropertyChangeListener  ;
34  import java.beans.VetoableChangeListener  ;
35  import java.text.Collator  ;
36  
37  import com.sun.jdo.api.persistence.model.ModelException;
38  import com.sun.jdo.spi.persistence.utility.I18NHelper;
39  
40  /** 
41   *
42   * @author raccah
43   * @version %I%
44   */
45  public abstract class PersistenceElement extends Object  
46      implements PersistenceElementProperties, Comparable  
47  {
48      /** I18N message handler */
49      private static final ResourceBundle   _messages = I18NHelper.loadBundle(
50          "com.sun.jdo.api.persistence.model.Bundle",     // NOI18N
51          PersistenceElement.class.getClassLoader());
52  
53      /** Implementation */
54      Impl _impl;
55  
56      /** Create new PersistenceElement with no implementation. 
57       * This constructor should only be used for cloning and archiving.
58       */
59      public PersistenceElement ()
60      {
61          this(null);
62      }
63  
64      /** Create new PersistenceElement with the provided implementation. The 
65       * implementation is responsible for storing all properties of the object.
66       * @param impl the implementation to use
67       */
68      protected PersistenceElement (PersistenceElement.Impl impl)
69      {
70          setImpl(impl);
71      }
72  
73      /** @return implemetation factory for this element
74       */
75      public final Impl getImpl () { return _impl; }
76  
77      /** @return I18N message handler for this element
78       */
79      protected static final ResourceBundle   getMessages () { return _messages; }
80  
81      /** Add a property change listener.
82       * @param l the listener to add
83       * @see PersistenceElementProperties
84       */
85      public final void addPropertyChangeListener (PropertyChangeListener   l)
86      {
87          getImpl().addPropertyChangeListener(l);
88      }
89  
90      /** Remove a property change listener.
91       * @param l the listener to remove
92       * @see PersistenceElementProperties
93       */
94      public final void removePropertyChangeListener (PropertyChangeListener   l)
95      {
96          getImpl().removePropertyChangeListener(l);
97      }
98  
99      /** Add a vetoable change listener.
100      * @param l the listener to add
101      * @see PersistenceElementProperties
102      */
103     public final void addVetoableChangeListener (VetoableChangeListener   l)
104     {
105         getImpl().addVetoableChangeListener(l);
106     }
107 
108     /** Remove a vetoable change listener.
109      * @param l the listener to remove
110      * @see PersistenceElementProperties
111      */
112     public final void removeVetoableChangeListener (VetoableChangeListener   l)
113     {
114         getImpl().removeVetoableChangeListener(l);
115     }
116 
117     /** Get the name of this persistence element.
118      * @return the name
119      */
120     public String   getName() { return getImpl().getName(); }
121 
122     /** Set the name of this persistence element.
123      * @param name the name
124      * @exception ModelException if impossible
125      */
126     public void setName (String   name) throws ModelException
127     {
128         getImpl().setName(name);
129     }
130     
131     /** Overrides Object's <code>toString</code> method to return the name 
132      * of this persistence element.
133      * @return a string representation of the object
134      */
135     public String   toString () { return getName(); }
136 
137     /** Overrides Object's <code>equals</code> method by comparing the name of this persistence element
138      * with the name of the argument obj. The method returns <code>false</code> if obj does not have 
139      * the same dynamic type as this persistence element.
140      * @return <code>true</code> if this object is the same as the obj argument; <code>false</code> otherwise.
141      * @param obj the reference object with which to compare.
142      */
143     public boolean equals(Object   obj)
144     {
145         if (obj == null)
146             return false;
147         if (obj == this)
148             return true;
149 
150         // check for the right class and then do the name check by calling compareTo.
151         return (getClass() == obj.getClass()) && (compareTo(obj) == 0);
152     }
153     
154     /** Overrides Object's <code>hashCode</code> method to return the hashCode of this persistence element's name.
155      * @return a hash code value for this object.
156      */
157     public int hashCode()
158     {
159         return (getName()==null) ? 0 : getName().hashCode();
160     }
161 
162     //================= implementation of Comparable ================
163     
164     /** Compares this object with the specified object for order. Returns a negative integer, zero, 
165      * or a positive integer as this object is less than, equal to, or greater than the specified object.
166      * The specified object must be persistence element, meaning it must be an instance of class 
167      * PersistenceElement or any subclass. If not a ClassCastException is thrown.
168      * The order of PersistenceElement objects is defined by the order of their names.
169      * Persistence elements without name are considered to be less than any named persistence element.
170      * @param o the Object to be compared.
171      * @return a negative integer, zero, or a positive integer as this object is less than, equal to, 
172      * or greater than the specified object.
173      * @exception ClassCastException - if the specified object is null or is not an instance of PersistenceElement
174      */
175     public int compareTo(Object   o)
176     {
177         // null is not allowed
178         if (o == null)
179             throw new ClassCastException  ();
180         if (o == this)
181             return 0;
182 
183         String   thisName = getName();
184         // the following statement throws a ClassCastException if o is not a PersistenceElement
185         String   otherName = ((PersistenceElement)o).getName();
186         // if this does not have a name it should compare less than any named object
187         if (thisName == null)
188             return (otherName == null) ? 0 : -1;
189         // if this is named and o does not have a name it should compare greater
190         if (otherName == null)
191             return 1;
192         // now we know that this and o are named persistence elements => 
193         // use locale-sensitive String comparison 
194         int ret = Collator.getInstance().compare(thisName, otherName);
195         // if both names are equal, both objects might have different types. 
196         // If so order both objects by their type names (necessary to be consistent with equals)
197         if ((ret == 0) && (getClass() != o.getClass()))
198             ret = getClass().getName().compareTo(o.getClass().getName());
199         return ret;
200     }
201     
202     //=============== extra set methods needed for xml archiver ==============
203 
204     /** Set the implementation factory of this persistence element.  
205      * This method should only be used internally and for cloning 
206      * and archiving.
207      * @param impl the implementation to use
208      */
209     public void setImpl (PersistenceElement.Impl impl)
210     {
211         _impl = impl;
212 
213         if (_impl != null)
214             getImpl().attachToElement(this);
215     }
216 
217     /** Pluggable implementation of the storage of element properties.
218      * @see PersistenceElement#PersistenceElement
219      */
220     public interface Impl
221     {
222         /** Add some items. */
223         public static final int ADD = 1;
224         /** Remove some items. */
225         public static final int REMOVE = -1;
226         /** Set some items, replacing the old ones. */
227         public static final int SET = 0;
228         
229         /** Called to attach the implementation to a specific
230          * element. Will be called in the element's constructor.
231          * Allows implementors of this interface to store a reference to the
232          * holder class, useful for implementing the property change listeners.
233          *
234          * @param element the element to attach to
235          */
236         public void attachToElement (PersistenceElement element);
237 
238         /** Add a property change listener.
239          * @param l the listener to add
240          */
241         public void addPropertyChangeListener (PropertyChangeListener   l);
242 
243         /** Remove a property change listener.
244          * @param l the listener to remove
245          */
246         public void removePropertyChangeListener (PropertyChangeListener   l);
247 
248         /** Add a vetoable change listener.
249          * @param l the listener to add
250          */
251         public void addVetoableChangeListener (VetoableChangeListener   l);
252 
253         /** Remove a vetoable change listener.
254          * @param l the listener to remove
255          */
256         public void removeVetoableChangeListener (VetoableChangeListener   l);
257 
258         /** Get the name of this persistence element.
259          * @return the name
260          */
261         public String   getName ();
262 
263         /** Set the name of this persistence element.
264          * @param name the name
265          * @exception ModelException if impossible
266          */
267         public void setName (String   name) throws ModelException;
268     }
269 }
270
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags