/*
* The parameter is a map that maps the nodeName to a list of ZNRecords.
*/
public List<ZNRecord> computeExternalView(
Map<String, List<ZNRecord>> currentStates, List<ZNRecord> idealStates) {
List<ZNRecord> resultList = new ArrayList<ZNRecord>();
Map<String, ZNRecord> resultRoutingTable = new HashMap<String, ZNRecord>();
// maps from resourceName to another map : partition -> map <nodename,
// master/slave>;
// Fill the routing table with "empty" default state according to ideals
// states
// in the cluster
if (idealStates != null) {
for (ZNRecord idealState : idealStates) {
ZNRecord defaultExternalView = new ZNRecord(idealState.getId());
resultRoutingTable.put(idealState.getId(), defaultExternalView);
}
} else {
assert (!currentStates.isEmpty());
return resultList;
}
for (String nodeName : currentStates.keySet()) {
List<ZNRecord> znStates = currentStates.get(nodeName);
for (ZNRecord nodeStateRecord : znStates) {
Map<String, Map<String, String>> resourceStates = nodeStateRecord.getMapFields();
for (String stateUnitKey : resourceStates.keySet()) {
Map<String, String> partitionStates = resourceStates.get(stateUnitKey);
String resourceName = partitionStates.get(Message.Attributes.RESOURCE_NAME.toString());
ZNRecord partitionStatus = resultRoutingTable.get(resourceName);
if (partitionStatus == null) {
partitionStatus = new ZNRecord(resourceName);
resultRoutingTable.put(resourceName, partitionStatus);
}
String currentStateKey = CurrentStateProperty.CURRENT_STATE.toString();
if (!partitionStatus.getMapFields().containsKey(stateUnitKey)) {
partitionStatus.setMapField(stateUnitKey, new TreeMap<String, String>());
}
partitionStatus
.getMapField(stateUnitKey)
.put(nodeName, partitionStates.get(currentStateKey));
}
}
}
for (ZNRecord record : resultRoutingTable.values()) {
resultList.add(record);
}
return resultList;
}
/*
* Given a list of external view ZNRecord nodes(one for each cluster),
* calculate the routing map.
* The format of the routing map is like this:
* Map<String, Map<String, Set<String>>> maps from a partitionName to its
* states Map<String, List<String>> The second Map maps from a state
* ("MASTER", "SLAVE"...) to a list of nodeNames
* So that the we can query the map for the list of nodes by providing the
* partition name and the expected state.
*/
public Map<String, Map<String, Set<String>>> getRouterMapFromExternalView(
List<ZNRecord> externalViewList) {
Map<String, Map<String, Set<String>>> result = new TreeMap<String, Map<String, Set<String>>>();
for (ZNRecord nodeView : externalViewList) {
Map<String, Map<String, String>> partitionNodeStateMap = nodeView.getMapFields();
for (String partitionId : partitionNodeStateMap.keySet()) {
if (!result.containsKey(partitionId)) {
result.put(partitionId, new TreeMap<String, Set<String>>());
}
Map<String, String> nodeStateMap = partitionNodeStateMap.get(partitionId);
for (String nodeName : nodeStateMap.keySet()) {
String state = nodeStateMap.get(nodeName);
if (!result.get(partitionId).containsKey(state)) {
result.get(partitionId).put(state, new TreeSet<String>());
}
result.get(partitionId).get(state).add(nodeName);
}
}
}
return result;
}