On Wed, 29 Nov 2000 09:44:04 -0500, Ruoqi Chen <[EMAIL PROTECTED]>
wrote:
>Rickard,
>
>May you tell me how to synchronize the static hashtable of a bean? Is
>synchronization allowed in beans?
First, yes it is allowed since this is static read-only state. I don't
want to pick up the discussion again on what is allowed and what is not
allowed. This Will Work.
Here's what you should do. In your stateless session bean have a static
field with a hashtable:
static Hashtable valueCache = new Hashtable();
in your session bean code you should use it as follows:
public Collection getValues(String key)
{
Collection values = valueCache.get(key);
if (values == null)
{
// Load values from DB
values = ...
valueCache.put(key, values);
}
return values
}
Since java.util.Hashtable is synchronized there is no chance for two
threads to update it simultaneously.
The above pattern will allow you to put the list in a database, but
cache it so that the DB is not used all the time for this static data.
If there is a chance that the value list is updated during the
application lifetime (i.e. it is semi-static), then just add a timeout
that clears the cache at regular intervals. It will be reloaded the next
time it is used.
regards,
Rickard
--
Rickard �berg
Email: [EMAIL PROTECTED]
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