Removing data from hashtable - blackberry

Question

I am adding some data in hashtable fetched from persistent store in blackberry,the use case is like for each date i get some data add it to persistent store.Now i have some data already in persistent store for date ,which i need to delete/update it and add the new data for that date,but the problem is the data is getting appended to the same date without removing the old data for that date.
public Hashtable getUserInfo() {
Hashtable eventBean = null;
store = PersistentStore.getPersistentObject(0xeb263c815d29213aL);
synchronized (store) {
eventBean = (Hashtable) store.getContents();
if (eventBean == null) {
eventBean = new Hashtable();
}
}
return eventBean;
}
private Hashtable getEvents(String usrDate, String timezone) {
listUserEvents = getUserInfo();
listEvents = new Vector();
Enumeration events = eventList.items();
while (events.hasMoreElements()) {
System.out.println("in while");
Event event = (Event) events.nextElement();
if (eventList.isSupportedField(Event.START) &&
event.countValues(Event.START) > 0)
{
long start = event.getDate(Event.START, 0);
SimpleDateFormat sdf =
new SimpleDateFormat("MMM dd,yyyy HH:mm");
String dateString = sdf.formatLocal(start);
SimpleDateFormat sdf1 =
new SimpleDateFormat("MMM dd,yyyy");
String date = sdf1.formatLocal(start);
System.out.println("dates are :" +date+ "user" +usrDate);
if (usrDate.equalsIgnoreCase(date)) {
System.out.println("dates are equal:" +date);
EventsBean eventBean = new EventsBean();
if (eventList.isSupportedField(Event.END) &&
event.countValues(Event.END) > 0)
{
long end = event.getDate(Event.END, 0);
SimpleDateFormat sdform =
new SimpleDateFormat("MMM dd, yyyy HH:mm");
String dateString1 = sdform.formatLocal(end);
eventBean.setStartDate(dateString);
eventBean.setEndDate(dateString1);
}
listEvents.addElement(eventBean);
System.out.println("the size bf hash is" + listEvents.size());
// changed it
if (listUserEvents.containsKey(usrDate)) {
Vector info = (Vector) listUserEvents.get(usrDate);
System.out.println("the size in getEvents is" +
info.size());
info.addElement(eventBean);
System.out.println("vector size info is" + info.size());
listUserEvents.put(usrDate, info);
} else {
listUserEvents.put(usrDate, listEvents);
}
} else {
// Dialog.alert("not equal");
}
}
}
}

Answer 1

You simply need to clear the old data from the vector stored for the date:
// changed it
if (listUserEvents.containsKey(usrDate)) {
Vector info = (Vector) listUserEvents.get(usrDate);
System.out.println("the size in getEvents is" +
info.size());
info.removeAllElements(); // <=== clears the old data
info.addElement(eventBean);
System.out.println("vector size info is" + info.size());
listUserEvents.put(usrDate, info);
} else {
listUserEvents.put(usrDate, listEvents);
}

Answer 2

Use the Following code to remove element from a vector at position i.
vector.removeElementAt(i);
Then add this vector to the persistent store. Every time update the vector and add the vector to the store.