DBElement


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11   * If applicable, add the following below the CDDL Header, with the fields
12   * enclosed by brackets [] replaced by your own identifying information:
13   * "Portions Copyrighted [year] [name of copyright owner]"
14   *
15   * The Original Software is NetBeans. The Initial Developer of the Original
16   * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
17   * Microsystems, Inc. All Rights Reserved.
18   */
19  
20  package org.netbeans.modules.dbschema;
21  
22  import java.beans.PropertyChangeListener  ;
23  import java.beans.PropertyChangeSupport  ;
24  import java.text.Collator  ;
25  
26  /** Base class for representations of elements corresponding to the database metadata.
27   */
28  public abstract class DBElement implements Comparable  , DBElementProperties {
29  
30      /** Implementation */
31      Impl impl;
32  
33      /** Default constructor.
34       */
35      public DBElement() {
36      }
37  
38      /** Creates a new element with the provided implementation. The implementation
39       * is responsible for storing all properties of the object.
40       * @param impl the implementation to use
41       */
42      protected DBElement(Impl impl)    {
43          this.impl = impl;
44          impl.attachToElement(this);
45      }
46  
47      /** Returns the implementation of the element.
48       * @return implementation for the element
49       */
50      public final Impl getElementImpl() {
51          return (DBElement.Impl) impl;
52      }
53  
54     /** Sets the implementation factory of this database element.
55       * This method should only be used internally and for cloning
56       * and archiving.
57       * @param impl the implementation to use
58       */
59      public void setElementImpl (DBElement.Impl anImpl) {
60          impl = anImpl;
61  
62          if (impl != null)
63              impl.attachToElement(this);
64      }
65  
66      /** Gets the name of this element.
67       * @return the name
68       */
69      public DBIdentifier getName() { //cannot be final because of overriding in ColumnPairElement
70          DBIdentifier name = getElementImpl().getName();
71          
72          return name;
73      }
74      
75      /** Sets the name of this element.
76      * @param name the name
77      * @throws DBException if impossible
78      */
79      public final void setName(DBIdentifier name) throws DBException {
80          getElementImpl().setName(name);
81      }
82  
83      /** Add a property change listener.
84       * @param l the listener to add
85       * @see DBElementProperties
86       */
87      public final void addPropertyChangeListener(PropertyChangeListener   l)    {
88          getElementImpl().addPropertyChangeListener(l);
89      }
90  
91      /** Remove a property change listener.
92       * @param l the listener to remove
93       * @see DBElementProperties
94       */
95      public final void removePropertyChangeListener(PropertyChangeListener   l) {
96          getElementImpl().removePropertyChangeListener(l);
97      }
98  
99      /** Gets a string representation of the element.
100      * @return the string
101      */
102     public String   toString() {
103         return getName().toString();
104     }
105 
106     /** Compares two elements.
107      * @param obj the reference object with which to compare.
108      * @return the value 0 if the argument object is equal to
109      * this object; -1 if this object is less than the object
110      * argument; and 1 if this object is greater than the object argument.
111      * Null objects are "smaller".
112      */
113     public int compareTo(Object   obj) {
114         // null is not allowed
115         if (obj == null)
116             throw new ClassCastException  ();
117         if (obj == this)
118             return 0;
119 
120         String   thisName = getName().getFullName();
121         String   otherName = ((DBElement) obj).getName().getFullName();
122         
123         if (thisName == null)
124             return (otherName == null) ? 0 : -1;
125             
126         if (otherName == null)
127             return 1;
128             
129         int ret = Collator.getInstance().compare(thisName, otherName);
130         // if both names are equal, both objects might have different types.
131         // If so order both objects by their type names 
132         // (necessary to be consistent with equals)
133         if ((ret == 0) && (getClass() != obj.getClass()))
134             ret = getClass().getName().compareTo(obj.getClass().getName());
135         
136         return ret;
137     }
138     
139     /** Indicates whether some other object is "equal to" this one.
140      * @return true if this object is the same as the obj argument; false otherwise.
141      */
142     public boolean equals(Object   obj) {
143         if (obj == null)
144             return false;
145         if (obj == this)
146             return true;
147 
148         // check for the right class and then do the name check
149         // by calling compareTo.
150         return (getClass() == obj.getClass()) && (compareTo(obj) == 0);
151     }
152     
153     /** Returns a hash code value for the element.
154      * @return a hash code value for this object.
155      */
156     public int hashCode() {
157         return (getName() != null && getName().getFullName() != null) ? getName().getFullName().hashCode() : 0;
158     }
159     
160     
161     /** Pluggable implementation of the storage of element properties.
162     * @see DBElement#DBElement
163     */
164     public interface Impl {
165         /** Add some items. */
166         public static final int ADD = 1;
167         /** Remove some items. */
168         public static final int REMOVE = -1;
169         /** Set some items, replacing the old ones. */
170         public static final int SET = 0;
171 
172         /** Called to attach the implementation to a specific
173          * element. Will be called in the element's constructor.
174          * Allows implementors of this interface to store a reference to the
175          * holder class, useful for implementing the property change listeners.
176          *
177          * @param element the element to attach to
178          */
179         public void attachToElement(DBElement el);
180 
181         /** Get the name of this element.
182          * @return the name
183          */
184         public DBIdentifier getName();
185 
186         /** Set the name of this element.
187          * @param name the name
188          * @throws DBException if impossible
189          */
190         public void setName(DBIdentifier name) throws DBException;
191 
192         /** Add a property change listener.
193         * @param l the listener to add
194         */
195         public void addPropertyChangeListener(PropertyChangeListener   l);
196 
197         /** Remove a property change listener.
198          * @param l the listener to remove
199          */
200         public void removePropertyChangeListener(PropertyChangeListener   l);
201     }
202 
203     /** Default implementation of the Impl interface.
204      * It just holds the property values.
205      */
206     static abstract class Memory implements DBElement.Impl {
207         /** the element for this implementation */
208         protected DBElement _element;
209 
210         /** Name of this element */
211         private DBIdentifier _name;
212 
213         /** Property change support */
214         private PropertyChangeSupport   support;
215 
216         /** Constructor */
217         public Memory() {
218             super();
219         }
220 
221         /** Copy */
222         public Memory(DBElement el) {
223             super();
224             _name = el.getName();
225         }
226 
227         /** Attaches to element */
228         public void attachToElement(DBElement element) {
229             _element = element;
230         }
231 
232         /** Getter for name of the element.
233          * @return the name
234          */
235         public final synchronized DBIdentifier getName() {
236             if (_name == null)        // lazy initialization !?
237                 _name = DBIdentifier.create(""); //NOI18N
238 
239             return _name;
240         }
241 
242         /** Setter for name of the element.
243          * @param name the name of the element
244          */
245         public synchronized void setName(DBIdentifier name) {
246             DBIdentifier old = _name;
247 
248             _name = name;
249             firePropertyChange(PROP_NAME, old, name);
250         }
251 
252         /** Fires property change event.
253          * @param name property name
254          * @param o old value
255          * @param n new value
256          */
257         protected final void firePropertyChange(String   name, Object   o, Object   n) {
258             if (support != null)
259                 support.firePropertyChange(name, o, n);
260         }
261 
262         /** Adds property listener */
263         public synchronized void addPropertyChangeListener(PropertyChangeListener   l) {
264             if (support == null)
265                 synchronized (this) {
266                     // new test under synchronized block
267                     if (support == null)
268                         support = new PropertyChangeSupport  (_element);
269                 }
270 
271             support.addPropertyChangeListener(l);
272         }
273 
274         /** Removes property listener */
275         public void removePropertyChangeListener (PropertyChangeListener   l) {
276             if (support != null)
277                 support.removePropertyChangeListener(l);
278         }
279     }
280 }
281
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