/** Subscribe for value updates. */
private void subscribe() {
synchronized (this) {
// Prevent multiple subscriptions.
if (subscription != null) {
return;
}
// Late callback, channel already closed?
final RefCountedChannel ch_ref = channel_ref;
if (ch_ref == null) {
return;
}
final Channel channel = ch_ref.getChannel();
// final Logger logger = Activator.getLogger();
try {
if (channel.getConnectionState() != Channel.CONNECTED) {
return;
}
//
// the RefCountedChannel should maintain a single
// subscription to the underlying CAJ/JCA channel.
// So even with N PVs for the same channel, it's
// only one subscription on the network instead of
// N subscriptions.
final DBRType type = DBR_Helper.getTimeType(plain, channel.getFieldType());
state = PVConnectionState.Subscribing;
totalMetaInfo.setStartTime(System.currentTimeMillis());
// isnotTimestampDBR
if (this.name.endsWith(".RTYP")) {
subscription = channel.addMonitor(MonitorMask.ARCHIVE.getMask(), this);
} else {
subscription =
channel.addMonitor(
type, channel.getElementCount(), MonitorMask.ARCHIVE.getMask(), this);
}
} catch (final Exception ex) {
logger.error("exception when subscribing pv " + name, ex);
}
}
}
