Retourner un ID non utilisé DB4O
bonjour
alors voila j'utilise DB4O et j'ai fait une classe qui la gère pour mon cas spécifique
c'est a dire la gestion des pannes
je voudrait faire une fonction qui me retourne un ID non utilisé
j'ai essayer cela :
Code:
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| public String getIDunused ( String NomClasse ) {
/* parcour DB4O et retourne un id non utilisé en fonction de la classe */
NomClasse = NomClasse.toLowerCase() ;
String ID = new String();
ObjectSet<ordinateur> result = this.getlesOrdinateurs() ;
ArrayList<String> tabID = new ArrayList<String>();
ID = null ;
for (Integer i = 0; i < result.size(); i++) {
ordinateur UnOrdinateur = result.get(i);
System.out.println("i :"+ i.toString());
tabID.add( UnOrdinateur.getID());
}
Integer j = null ;
/* while ((ID == null )) {
String sj = j.toString() ;
System.out.println("j :"+j);
if (!(tabID.contains(sj))) { ID = sj ;}
}*/
do {
String sj = j.toString() ;
System.out.println("j :"+j);
if (!(tabID.contains(sj))) { ID = sj ;}
} while (!(ID.equals(null)) );
return ID ;
} |
ca me met :
Citation:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
i :1
i :2
i :3
at clst.DB4O_GestPanne.getIDunused(DB4O_GestPanne.java:163)
at ihm.ordinateur.pan_OrdiAjout.<init>(pan_OrdiAjout.java:29)
at ihm.Frm_main.menu_ajoutordiActionPerformed(Frm_main.java:214)
at ihm.Frm_main.access$100(Frm_main.java:23)
at ihm.Frm_main$2.actionPerformed(Frm_main.java:77)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:809)
at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:850)
at java.awt.Component.processMouseEvent(Component.java:6289)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
at java.awt.Component.processEvent(Component.java:6054)
at java.awt.Container.processEvent(Container.java:2041)
at java.awt.Component.dispatchEventImpl(Component.java:4652)
at java.awt.Container.dispatchEventImpl(Container.java:2099)
at java.awt.Component.dispatchEvent(Component.java:4482)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4577)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
at java.awt.Container.dispatchEventImpl(Container.java:2085)
at java.awt.Window.dispatchEventImpl(Window.java:2478)
at java.awt.Component.dispatchEvent(Component.java:4482)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:644)
at java.awt.EventQueue.access$000(EventQueue.java:85)
at java.awt.EventQueue$1.run(EventQueue.java:603)
at java.awt.EventQueue$1.run(EventQueue.java:601)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
at java.awt.EventQueue$2.run(EventQueue.java:617)
at java.awt.EventQueue$2.run(EventQueue.java:615)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:614)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
quelqu'un connait un solution ?
cordialement