import com.allanbank.mongodb.bson.Document; //导入方法依赖的package包/类
/**
* Extract the number of seconds this Server is behind the primary by
* comparing its latest optime with that of the absolute latest optime.
*
* To account for idle servers we use the optime for each server and assign
* a value of zero to the "latest" optime and then subtract the remaining
* servers from that optime.
*
*
* Lastly, the state of the server is also checked and the seconds behind is
* set to {@link Double#MAX_VALUE} if not in the primary (
* {@value #PRIMARY_STATE}) or secondary ({@value #SECONDARY_STATE}).
*
*
* @param replicaStateDoc
* The document to extract the seconds behind from.
*/
private void updateSecondsBehind(final Document replicaStateDoc) {
final State oldValue = myState;
final NumericElement state = replicaStateDoc.get(NUMERIC_TYPE,
"myState");
if (state != null) {
final int value = state.getIntValue();
if (value == PRIMARY_STATE) {
myState = State.WRITABLE;
mySecondsBehind = 0;
}
else if (value == SECONDARY_STATE) {
myState = State.READ_ONLY;
TimestampElement serverTimestamp = null;
final StringElement expectedName = new StringElement("name",
myCanonicalName);
for (final DocumentElement member : replicaStateDoc.find(
DOCUMENT_TYPE, "members", ".*")) {
if (expectedName.equals(member.get("name"))
&& (member.get(TIMESTAMP_TYPE, "optimeDate") != null)) {
serverTimestamp = member.get(TIMESTAMP_TYPE,
"optimeDate");
}
}
if (serverTimestamp != null) {
TimestampElement latestTimestamp = serverTimestamp;
for (final TimestampElement time : replicaStateDoc.find(
TIMESTAMP_TYPE, "members", ".*", "optimeDate")) {
if (latestTimestamp.getTime() < time.getTime()) {
latestTimestamp = time;
}
}
final double msBehind = latestTimestamp.getTime()
- serverTimestamp.getTime();
mySecondsBehind = (msBehind / TimeUnit.SECONDS.toMillis(1));
}
}
else {
// "myState" != 1 and "myState" != 2
mySecondsBehind = Double.MAX_VALUE;
myState = State.UNAVAILABLE;
}
}
myEventSupport.firePropertyChange(STATE_PROP, oldValue, myState);
}
)
)
