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package com.orbekk.same;
import com.orbekk.same.State.Component;
import java.util.Collections;
import java.util.List;
import com.orbekk.util.WorkQueue;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Master {
private Logger logger = LoggerFactory.getLogger(getClass());
private final ConnectionManager connections;
private String myUrl;
State state;
private Broadcaster broadcaster;
private volatile int masterId = 0;
public static Master create(ConnectionManager connections,
Broadcaster broadcaster, String myUrl, String networkName) {
State state = new State(networkName);
state.update(".masterUrl", myUrl, 1);
return new Master(state, connections, broadcaster, myUrl);
}
Master(State initialState, ConnectionManager connections,
Broadcaster broadcaster, String myUrl) {
this.state = initialState;
this.connections = connections;
this.broadcaster = broadcaster;
this.myUrl = myUrl;
}
public String getUrl() {
return myUrl;
}
private MasterService serviceImpl = new MasterService() {
@Override
public boolean updateStateRequest(String component,
String newData, long revision) {
logger.info("updateStateRequest({}, {}, {})",
new Object[]{component, newData, revision});
boolean updated = state.update(component, newData, revision + 1);
if (updated) {
updateStateRequestThread.add(component);
}
return updated;
}
@Override
public void joinNetworkRequest(String clientUrl) {
logger.info("joinNetworkRequest({})", clientUrl);
List<String> participants = state.getList(".participants");
sendFullStateThread.add(clientUrl);
if (!participants.contains(clientUrl)) {
participants.add(clientUrl);
synchronized (Master.this) {
state.updateFromObject(".participants", participants,
state.getRevision(".participants") + 1);
}
updateStateRequestThread.add(".participants");
} else {
logger.warn("Client {} joining: Already part of network");
}
}
};
WorkQueue<String> updateStateRequestThread = new WorkQueue<String>() {
@Override protected void onChange() {
List<String> pending = getAndClear();
logger.info("updateStateRequestThread: Updated state: {}",
pending);
for (String componentName : pending) {
Component component = state.getComponent(componentName);
List<String> participants = state.getList(".participants");
broadcastNewComponents(participants,
Collections.singletonList(component));
}
}
};
WorkQueue<String> sendFullStateThread = new WorkQueue<String>() {
@Override protected void onChange() {
List<String> pending = getAndClear();
logger.info("Sending full state to {}", pending);
final List<Component> components = state.getComponents();
broadcaster.broadcast(pending, new ServiceOperation() {
@Override public void run(String url) {
ClientService client = connections.getClient(url);
try {
client.masterTakeover(
state.getDataOf(".masterUrl"),
state.getDataOf(".networkName"),
masterId);
} catch (Exception e) {
logger.info("Client {} failed to acknowledge master. Remove.");
removeParticipant(url);
}
}
});
broadcastNewComponents(pending, components);
}
};
void performWork() {
sendFullStateThread.performWork();
updateStateRequestThread.performWork();
}
public void start() {
sendFullStateThread.start();
updateStateRequestThread.start();
}
public void interrupt() {
sendFullStateThread.interrupt();
updateStateRequestThread.interrupt();
}
public MasterService getService() {
return serviceImpl;
}
private synchronized void removeParticipant(String url) {
List<String> participants = state.getList(".participants");
if (participants.contains(url)) {
logger.info("removeParticipant({})", url);
participants.remove(url);
state.updateFromObject(".participants", participants,
state.getRevision(".participants") + 1);
updateStateRequestThread.add(".participants");
}
}
private void broadcastNewComponents(List<String> destinations,
final List<State.Component> components) {
broadcaster.broadcast(destinations, new ServiceOperation() {
@Override public void run(String url) {
ClientService client = connections.getClient(url);
try {
for (Component c : components) {
client.setState(c.getName(), c.getData(),
c.getRevision());
}
} catch (Exception e) {
logger.info("Client {} failed to receive state update.", url);
removeParticipant(url);
}
}
});
}
/** This master should take over from an earlier master. */
public void resumeFrom(State lastKnownState, final int masterId) {
state = lastKnownState;
state.update(".masterUrl", myUrl, state.getRevision(".masterUrl") + 100);
this.masterId = masterId;
broadcaster.broadcast(state.getList(".participants"),
new ServiceOperation() {
@Override
public void run(String url) {
ClientService client = connections.getClient(url);
try {
client.masterTakeover(myUrl,
state.getDataOf(".networkName"), masterId);
} catch (Exception e) {
logger.info("Client {} failed to acknowledge new master. " +
"Removing {}", url);
removeParticipant(url);
}
}
});
}
}
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