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/**
* Copyright 2012 Kjetil Ørbekk <kjetil.orbekk@gmail.com>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.orbekk.same;
import java.util.List;
import java.util.concurrent.atomic.AtomicLong;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.protobuf.RpcCallback;
import com.google.protobuf.RpcController;
import com.orbekk.protobuf.Rpc;
import com.orbekk.same.Services.ClientState;
import com.orbekk.same.Services.Empty;
import com.orbekk.same.Services.MasterTakeoverResponse;
import com.orbekk.same.State.Component;
public class Master {
private Logger logger = LoggerFactory.getLogger(getClass());
private final ConnectionManager connections;
private String myLocation; // Protobuf server location, i.e., myIp:port
private String networkName;
private AtomicLong revision = new AtomicLong(1);
State state;
private volatile int masterId = 1;
private final RpcFactory rpcf;
class RemoveParticipantIfFailsCallback<T> implements RpcCallback<T> {
private final String participantLocation;
private final Rpc rpc;
public RemoveParticipantIfFailsCallback(
String participantLocation, Rpc rpc) {
this.participantLocation = participantLocation;
this.rpc = rpc;
}
@Override
public void run(T unused) {
if (rpc.isOk()) {
if (rpc.failed()) {
removeParticipant(participantLocation);
}
}
}
}
public static Master create(ConnectionManager connections,
String myUrl, String networkName,
String myLocation, RpcFactory rpcf) {
State state = new State();
return new Master(state, connections, networkName, myLocation, rpcf);
}
Master(State initialState, ConnectionManager connections,
String networkName, String myLocation, RpcFactory rpcf) {
this.state = initialState;
this.connections = connections;
this.myLocation = myLocation;
this.networkName = networkName;
this.rpcf = rpcf;
}
public String getNetworkName() {
return networkName;
}
public String getLocation() {
return myLocation;
}
public Services.MasterState getMasterInfo() {
return Services.MasterState.newBuilder()
.setMasterLocation(getLocation())
.setNetworkName(getNetworkName())
.setMasterId(masterId)
.setRevision(revision.get())
.build();
}
private Services.Master newMasterImpl = new Services.Master() {
@Override public void joinNetworkRequest(RpcController controller,
ClientState request, RpcCallback<Empty> done) {
sendInitialMasterTakeover(request.getLocation());
sendFullState(request.getLocation());
addParticipant(request.getLocation());
done.run(Empty.getDefaultInstance());
}
@Override public void updateStateRequest(RpcController controller,
Services.Component request,
RpcCallback<Services.UpdateComponentResponse> done) {
logger.info("updateStateRequest({})", request);
boolean success = false;
if (state.checkRevision(request.getId(), request.getRevision())) {
success = true;
long newRevision = revision.incrementAndGet();
state.forceUpdate(request.getId(), request.getData(), newRevision);
sendStateToClients(state.getComponent(request.getId()));
}
done.run(Services.UpdateComponentResponse.newBuilder()
.setSuccess(success).build());
}
};
private void sendStateToClients(State.Component component) {
for (String clientLocation : state.getList(
com.orbekk.same.State.PARTICIPANTS)) {
sendComponent(clientLocation, component);
}
}
private void sendComponent(String clientLocation, Component component) {
Services.Client client = connections.getClient0(clientLocation);
if (client == null) {
removeParticipant(clientLocation);
}
Services.Component componentProto = ServicesPbConversion.componentToPb(component);
Rpc rpc = rpcf.create();
RpcCallback<Empty> done =
new RemoveParticipantIfFailsCallback<Empty>(clientLocation,
rpc);
client.setState(rpc, componentProto, done);
}
private void sendComponents(String clientLocation,
List<Component> components) {
Services.Client client = connections.getClient0(clientLocation);
if (client == null) {
removeParticipant(clientLocation);
}
for (Component component : components) {
Services.Component componentProto = ServicesPbConversion.componentToPb(component);
Rpc rpc = rpcf.create();
RpcCallback<Empty> done =
new RemoveParticipantIfFailsCallback<Empty>(clientLocation,
rpc);
client.setState(rpc, componentProto, done);
}
}
private void sendFullState(String clientLocation) {
List<Component> components = state.getComponents();
sendComponents(clientLocation, components);
}
private void sendInitialMasterTakeover(String clientLocation) {
Services.Client client = connections.getClient0(clientLocation);
Rpc rpc = rpcf.create();
RpcCallback<MasterTakeoverResponse> done =
new RemoveParticipantIfFailsCallback<MasterTakeoverResponse>(
clientLocation, rpc);
client.masterTakeover(rpc, getMasterInfo(), done);
}
void performWork() {
}
public void start() {
}
public void interrupt() {
}
public Services.Master getNewService() {
return newMasterImpl;
}
private synchronized void addParticipant(String location) {
List<String> participants = state.getList(State.PARTICIPANTS);
if (!participants.contains(location)) {
participants.add(location);
state.updateFromObject(State.PARTICIPANTS, participants,
state.getRevision(State.PARTICIPANTS) + 1);
sendStateToClients(state.getComponent(State.PARTICIPANTS));
}
}
private synchronized void removeParticipant(String url) {
List<String> participants0 = state.getList(State.PARTICIPANTS);
if (participants0.contains(url)) {
logger.info("removeParticipant({})", url);
participants0.remove(url);
state.updateFromObject(State.PARTICIPANTS, participants0,
state.getRevision(State.PARTICIPANTS) + 1);
sendStateToClients(state.getComponent(State.PARTICIPANTS));
}
}
/** This master should take over from an earlier master. */
public void resumeFrom(State lastKnownState, final int masterId) {
state = lastKnownState;
this.masterId = masterId;
for (final String location : state.getList(State.PARTICIPANTS)) {
Services.Client client = connections.getClient0(location);
final Rpc rpc = rpcf.create();
RpcCallback<MasterTakeoverResponse> done = new RemoveParticipantIfFailsCallback<Services.MasterTakeoverResponse>(location, rpc);
if (client == null) {
removeParticipant(location);
continue;
}
client.masterTakeover(rpc, getMasterInfo(), done);
}
}
}
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