/**
* Determines the read preference that should be used for the given command.
*
* @param command the {@link DBObject} representing the command
* @param requestedPreference the preference requested by the client.
* @return the read preference to use for the given command. It will never return {@code null}.
* @see com.mongodb.ReadPreference
*/
ReadPreference getCommandReadPreference(DBObject command, ReadPreference requestedPreference) {
String comString = command.keySet().iterator().next();
if (comString.equals("getnonce") || comString.equals("authenticate")) {
return ReadPreference.primaryPreferred();
}
boolean primaryRequired;
// explicitly check mapreduce commands are inline
if (comString.equals("mapreduce")) {
Object out = command.get("out");
if (out instanceof BSONObject) {
BSONObject outMap = (BSONObject) out;
primaryRequired = outMap.get("inline") == null;
} else primaryRequired = true;
} else {
primaryRequired = !_obedientCommands.contains(comString.toLowerCase());
}
if (primaryRequired) {
return ReadPreference.primary();
} else if (requestedPreference == null) {
return ReadPreference.primary();
} else {
return requestedPreference;
}
}
@Test
public void testPrimaryPreferredWithNoPrimary() {
for (int i = 0; i < 1000; i++) {
nodeSet.add(ReadPreference.primaryPreferred().getNode(_setNoPrimary));
}
expectedNodeSet.addAll(Arrays.asList(_secondary1, _secondary2));
assertEquals(expectedNodeSet, nodeSet);
}
@Test
public void testTaggedPrimaryPreferredWithNoPrimary() {
final TaggableReadPreference readPreference =
ReadPreference.primaryPreferred(new BasicDBObject("dc", "ny"));
for (int i = 0; i < 1000; i++) {
nodeSet.add(readPreference.getNode(_setNoPrimary));
}
expectedNodeSet.addAll(Arrays.asList(_secondary1, _secondary2));
assertEquals(expectedNodeSet, nodeSet);
}
