MiG InfoCom MiG Calendar DBConnect Guide User Manual

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the queue and an exception is fired to the

ExceptionListener

It is then up to the listeners to handle the situation.

Loading only Visible Activities

The DBConnect activity poll does not out of the box know about what
date/time ranges the user are currently watching in the date areas.
This means that it will load all activities which is many times not
desirable, since keeping them all in memory can be too much. Even
though MiG Calendar can typically hold about 100.000 activities in a
normal PC's memory it will still reduce performance.

There is an easy way you can make DBConnect only load activities
that are visible. You can even add date ranges that are interesting
other than the ones handled automatically by the date areas. All date
areas (e.g.

DefaultDateArea

) register their visible date range as

Subscription

to the

ActivityDepository

. What you need

to do is to add a specific

WHERE

clause to the

DBDataProvider

that tells the database to only return activities between certain ranges.
Fortunately there is a utility method that creates this

SQLExpression

for you and it is even dynamic in that it reads the

active subscriptions for every call.

All you have to do is:

SQLExpression expr =
DBUtil.getDynamicActivitySubscriptionsSQLExpression("affect_start_millis",
"affect_end_millis", null);

DBDataProvider provider = (DBDataProvider) activitySynchronizer.getDataProvider()
provider.setReadWhereExpression(expr);

There is also a static version of the method above. It will create a filter
for the subscriptions as they are registered at the time of the method
call.

Custom Properties in Activities or Categories
Both the

Activity

and