Refactored various websockets to event bus from old BlockNotifier/StatusNotifier

src/main/java/org/qortal/api/websocket/AdminStatusWebSocket.java

@@ -13,59 +13,87 @@ import org.eclipse.jetty.websocket.api.annotations.OnWebSocketMessage;
 import org.eclipse.jetty.websocket.api.annotations.WebSocket;
 import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory;
 import org.qortal.api.model.NodeStatus;
-import org.qortal.controller.StatusNotifier;
+import org.qortal.controller.Controller;
-import org.qortal.repository.DataException;
+import org.qortal.event.Event;
-import org.qortal.repository.Repository;
+import org.qortal.event.EventBus;
-import org.qortal.repository.RepositoryManager;
+import org.qortal.event.Listener;
 
 @WebSocket
 @SuppressWarnings("serial")
-public class AdminStatusWebSocket extends ApiWebSocket {
+public class AdminStatusWebSocket extends ApiWebSocket implements Listener {
+
+	private static final AtomicReference<String> previousOutput = new AtomicReference<>(null);
 
 	@Override
 	public void configure(WebSocketServletFactory factory) {
 		factory.register(AdminStatusWebSocket.class);
+
+		try {
+			previousOutput.set(buildStatusString());
+		} catch (IOException e) {
+			// How to fail properly?
+			return;
+		}
+
+		EventBus.INSTANCE.addListener(this::listen);
+	}
+
+	@Override
+	public void listen(Event event) {
+		if (!(event instanceof Controller.StatusChangeEvent))
+			return;
+
+		String newOutput;
+		try {
+			newOutput = buildStatusString();
+		} catch (IOException e) {
+			// Ignore this time?
+			return;
+		}
+
+		if (previousOutput.getAndUpdate(currentValue -> newOutput).equals(newOutput))
+			// Output hasn't changed, so don't send anything
+			return;
+
+		for (Session session : getSessions())
+			this.sendStatus(session, newOutput);
 	}
 
 	@OnWebSocketConnect
+	@Override
 	public void onWebSocketConnect(Session session) {
-		AtomicReference<String> previousOutput = new AtomicReference<>(null);
+		this.sendStatus(session, previousOutput.get());
 
-		StatusNotifier.Listener listener = timestamp -> onNotify(session, previousOutput);
+		super.onWebSocketConnect(session);
-		StatusNotifier.getInstance().register(session, listener);
-
-		this.onNotify(session, previousOutput);
 	}
 
 	@OnWebSocketClose
+	@Override
 	public void onWebSocketClose(Session session, int statusCode, String reason) {
-		StatusNotifier.getInstance().deregister(session);
+		super.onWebSocketClose(session, statusCode, reason);
 	}
 
 	@OnWebSocketError
 	public void onWebSocketError(Session session, Throwable throwable) {
+		/* We ignore errors for now, but method here to silence log spam */
 	}
 
 	@OnWebSocketMessage
 	public void onWebSocketMessage(Session session, String message) {
+		/* ignored */
 	}
 
-	private void onNotify(Session session,AtomicReference<String> previousOutput) {
+	private static String buildStatusString() throws IOException {
-		try (final Repository repository = RepositoryManager.getRepository()) {
 		NodeStatus nodeStatus = new NodeStatus();
-
 		StringWriter stringWriter = new StringWriter();
-
 		marshall(stringWriter, nodeStatus);
+		return stringWriter.toString();
+	}
 
-			// Only output if something has changed
+	private void sendStatus(Session session, String status) {
-			String output = stringWriter.toString();
+		try {
-			if (output.equals(previousOutput.get()))
+			session.getRemote().sendStringByFuture(status);
-				return;
+		} catch (WebSocketException e) {
-
-			previousOutput.set(output);
-			session.getRemote().sendStringByFuture(output);
-		} catch (DataException | IOException | WebSocketException e) {
 			// No output this time?
 		}
 	}

src/main/java/org/qortal/api/websocket/BlocksWebSocket.java

@@ -14,7 +14,11 @@ import org.eclipse.jetty.websocket.api.annotations.WebSocket;
 import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory;
 import org.qortal.api.ApiError;
 import org.qortal.api.model.BlockInfo;
-import org.qortal.controller.BlockNotifier;
+import org.qortal.controller.Controller;
+import org.qortal.data.block.BlockData;
+import org.qortal.event.Event;
+import org.qortal.event.EventBus;
+import org.qortal.event.Listener;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.repository.RepositoryManager;
@@ -22,26 +26,42 @@ import org.qortal.utils.Base58;
 
 @WebSocket
 @SuppressWarnings("serial")
-public class BlocksWebSocket extends ApiWebSocket {
+public class BlocksWebSocket extends ApiWebSocket implements Listener {
 
 	@Override
 	public void configure(WebSocketServletFactory factory) {
 		factory.register(BlocksWebSocket.class);
+
+		EventBus.INSTANCE.addListener(this::listen);
+	}
+
+	@Override
+	public void listen(Event event) {
+		if (!(event instanceof Controller.NewBlockEvent))
+			return;
+
+		BlockData blockData = ((Controller.NewBlockEvent) event).getBlockData();
+		BlockInfo blockInfo = new BlockInfo(blockData);
+
+		for (Session session : getSessions())
+			sendBlockInfo(session, blockInfo);
 	}
 
 	@OnWebSocketConnect
+	@Override
 	public void onWebSocketConnect(Session session) {
-		BlockNotifier.Listener listener = blockInfo -> onNotify(session, blockInfo);
+		super.onWebSocketConnect(session);
-		BlockNotifier.getInstance().register(session, listener);
 	}
 
 	@OnWebSocketClose
+	@Override
 	public void onWebSocketClose(Session session, int statusCode, String reason) {
-		BlockNotifier.getInstance().deregister(session);
+		super.onWebSocketClose(session, statusCode, reason);
 	}
 
 	@OnWebSocketError
 	public void onWebSocketError(Session session, Throwable throwable) {
+		/* We ignore errors for now, but method here to silence log spam */
 	}
 
 	@OnWebSocketMessage
@@ -71,7 +91,7 @@ public class BlocksWebSocket extends ApiWebSocket {
 					return;
 				}
 
-				onNotify(session, blockInfos.get(0));
+				sendBlockInfo(session, blockInfos.get(0));
 			} catch (DataException e) {
 				sendError(session, ApiError.REPOSITORY_ISSUE);
 			}
@@ -100,13 +120,13 @@ public class BlocksWebSocket extends ApiWebSocket {
 				return;
 			}
 
-			onNotify(session, blockInfos.get(0));
+			sendBlockInfo(session, blockInfos.get(0));
 		} catch (DataException e) {
 			sendError(session, ApiError.REPOSITORY_ISSUE);
 		}
 	}
 
-	private void onNotify(Session session, BlockInfo blockInfo) {
+	private void sendBlockInfo(Session session, BlockInfo blockInfo) {
 		StringWriter stringWriter = new StringWriter();
 
 		try {

src/main/java/org/qortal/api/websocket/TradeOffersWebSocket.java

@@ -6,6 +6,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Predicate;
 import java.util.stream.Collectors;
 
 import org.eclipse.jetty.websocket.api.Session;
@@ -14,12 +15,15 @@ import org.eclipse.jetty.websocket.api.annotations.OnWebSocketConnect;
 import org.eclipse.jetty.websocket.api.annotations.OnWebSocketMessage;
 import org.eclipse.jetty.websocket.api.annotations.WebSocket;
 import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory;
-import org.qortal.api.model.BlockInfo;
 import org.qortal.api.model.CrossChainOfferSummary;
-import org.qortal.controller.BlockNotifier;
+import org.qortal.controller.Controller;
 import org.qortal.crosschain.BTCACCT;
 import org.qortal.data.at.ATStateData;
+import org.qortal.data.block.BlockData;
 import org.qortal.data.crosschain.CrossChainTradeData;
+import org.qortal.event.Event;
+import org.qortal.event.EventBus;
+import org.qortal.event.Listener;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.repository.RepositoryManager;
@@ -27,120 +31,56 @@ import org.qortal.utils.NTP;
 
 @WebSocket
 @SuppressWarnings("serial")
-public class TradeOffersWebSocket extends ApiWebSocket {
+public class TradeOffersWebSocket extends ApiWebSocket implements Listener {
+
+	private static final Map<String, BTCACCT.Mode> previousAtModes = new HashMap<>();
+
+	// OFFERING
+	private static final List<CrossChainOfferSummary> currentSummaries = new ArrayList<>();
+	// REDEEMED/REFUNDED/CANCELLED
+	private static final List<CrossChainOfferSummary> historicSummaries = new ArrayList<>();
+
+	private static final Predicate<CrossChainOfferSummary> isCurrent = offerSummary
+			-> offerSummary.getMode() == BTCACCT.Mode.OFFERING;
+
+	private static final Predicate<CrossChainOfferSummary> isHistoric = offerSummary
+			-> offerSummary.getMode() == BTCACCT.Mode.REDEEMED
+			|| offerSummary.getMode() == BTCACCT.Mode.REFUNDED
+			|| offerSummary.getMode() == BTCACCT.Mode.CANCELLED;
+
 
 	@Override
 	public void configure(WebSocketServletFactory factory) {
 		factory.register(TradeOffersWebSocket.class);
-	}
-
-	@OnWebSocketConnect
-	public void onWebSocketConnect(Session session) {
-		Map<String, List<String>> queryParams = session.getUpgradeRequest().getParameterMap();
-
-		final boolean includeHistoric = queryParams.get("includeHistoric") != null;
-		final Map<String, BTCACCT.Mode> previousAtModes = new HashMap<>();
-		List<CrossChainOfferSummary> crossChainOfferSummaries;
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
-			List<ATStateData> initialAtStates;
+			populateCurrentSummaries(repository);
-
-			// We want ALL OFFERING trades
-			Boolean isFinished = Boolean.FALSE;
-			Integer dataByteOffset = BTCACCT.MODE_BYTE_OFFSET;
-			Long expectedValue = (long) BTCACCT.Mode.OFFERING.value;
-			Integer minimumFinalHeight = null;
-
-			initialAtStates = repository.getATRepository().getMatchingFinalATStates(BTCACCT.CODE_BYTES_HASH,
-					isFinished, dataByteOffset, expectedValue, minimumFinalHeight,
-					null, null, null);
-
-			if (initialAtStates == null) {
-				session.close(4001, "repository issue fetching OFFERING trades");
-				return;
-			}
-
-			// Save initial AT modes
-			previousAtModes.putAll(initialAtStates.stream().collect(Collectors.toMap(ATStateData::getATAddress, atState -> BTCACCT.Mode.OFFERING)));
-
-			// Convert to offer summaries
-			crossChainOfferSummaries = produceSummaries(repository, initialAtStates, null);
-
-			if (includeHistoric) {
-				// We also want REDEEMED/REFUNDED/CANCELLED trades over the last 24 hours
-				long timestamp = NTP.getTime() - 24 * 60 * 60 * 1000L;
-				minimumFinalHeight = repository.getBlockRepository().getHeightFromTimestamp(timestamp);
-
-				if (minimumFinalHeight != 0) {
-					isFinished = Boolean.TRUE;
-					dataByteOffset = null;
-					expectedValue = null;
-					++minimumFinalHeight; // because height is just *before* timestamp
-
-					List<ATStateData> historicAtStates = repository.getATRepository().getMatchingFinalATStates(BTCACCT.CODE_BYTES_HASH,
-							isFinished, dataByteOffset, expectedValue, minimumFinalHeight,
-							null, null, null);
-
-					if (historicAtStates == null) {
-						session.close(4002, "repository issue fetching historic trades");
-						return;
-					}
-
-					for (ATStateData historicAtState : historicAtStates) {
-						CrossChainOfferSummary historicOfferSummary = produceSummary(repository, historicAtState, null);
-
-						switch (historicOfferSummary.getMode()) {
-							case REDEEMED:
-							case REFUNDED:
-							case CANCELLED:
-								break;
-
-							default:
-								continue;
-						}
-
-						// Add summary to initial burst
-						crossChainOfferSummaries.add(historicOfferSummary);
-
-						// Save initial AT mode
-						previousAtModes.put(historicAtState.getATAddress(), historicOfferSummary.getMode());
-					}
-				}
-			}
 
+			populateHistoricSummaries(repository);
 		} catch (DataException e) {
-			session.close(4003, "generic repository issue");
+			// How to fail properly?
 			return;
 		}
 
-		if (!sendOfferSummaries(session, crossChainOfferSummaries)) {
+		EventBus.INSTANCE.addListener(this::listen);
-			session.close(4004, "websocket issue");
+	}
+
+	@Override
+	public void listen(Event event) {
+		if (!(event instanceof Controller.NewBlockEvent))
 			return;
-		}
 
-		BlockNotifier.Listener listener = blockInfo -> onNotify(session, blockInfo, previousAtModes);
+		BlockData blockData = ((Controller.NewBlockEvent) event).getBlockData();
-		BlockNotifier.getInstance().register(session, listener);
-	}
 
-	@OnWebSocketClose
+		// Process any new info
-	public void onWebSocketClose(Session session, int statusCode, String reason) {
+		List<CrossChainOfferSummary> crossChainOfferSummaries;
-		BlockNotifier.getInstance().deregister(session);
-	}
-
-	@OnWebSocketMessage
-	public void onWebSocketMessage(Session session, String message) {
-		/* ignored */
-	}
-
-	private void onNotify(Session session, BlockInfo blockInfo, final Map<String, BTCACCT.Mode> previousAtModes) {
-		List<CrossChainOfferSummary> crossChainOfferSummaries = null;
 
 		try (final Repository repository = RepositoryManager.getRepository()) {
 			// Find any new trade ATs since this block
 			final Boolean isFinished = null;
 			final Integer dataByteOffset = null;
 			final Long expectedValue = null;
-			final Integer minimumFinalHeight = blockInfo.getHeight();
+			final Integer minimumFinalHeight = blockData.getHeight();
 
 			List<ATStateData> atStates = repository.getATRepository().getMatchingFinalATStates(BTCACCT.CODE_BYTES_HASH,
 					isFinished, dataByteOffset, expectedValue, minimumFinalHeight,
@@ -149,12 +89,13 @@ public class TradeOffersWebSocket extends ApiWebSocket {
 			if (atStates == null)
 				return;
 
-			crossChainOfferSummaries = produceSummaries(repository, atStates, blockInfo.getTimestamp());
+			crossChainOfferSummaries = produceSummaries(repository, atStates, blockData.getTimestamp());
 		} catch (DataException e) {
 			// No output this time
+			return;
 		}
 
-		synchronized (previousAtModes) { //NOSONAR squid:S2445 suppressed because previousAtModes is final and curried in lambda
+		synchronized (previousAtModes) {
 			// Remove any entries unchanged from last time
 			crossChainOfferSummaries.removeIf(offerSummary -> previousAtModes.get(offerSummary.getQortalAtAddress()) == offerSummary.getMode());
 
@@ -162,13 +103,63 @@ public class TradeOffersWebSocket extends ApiWebSocket {
 			if (crossChainOfferSummaries.isEmpty())
 				return;
 
-			final boolean wasSent = sendOfferSummaries(session, crossChainOfferSummaries);
+			// Update
-
-			if (!wasSent)
-				return;
-
 			previousAtModes.putAll(crossChainOfferSummaries.stream().collect(Collectors.toMap(CrossChainOfferSummary::getQortalAtAddress, CrossChainOfferSummary::getMode)));
+
+			synchronized (currentSummaries) {
+				// Add any OFFERING to 'current'
+				currentSummaries.addAll(crossChainOfferSummaries.stream().filter(isCurrent).collect(Collectors.toList()));
 			}
+
+			final long tooOldTimestamp = NTP.getTime() - 24 * 60 * 60 * 1000L;
+			synchronized (historicSummaries) {
+				// Add any REDEEMED/REFUNDED/CANCELLED
+				historicSummaries.addAll(crossChainOfferSummaries.stream().filter(isHistoric).collect(Collectors.toList()));
+
+				// But also remove any that are over 24 hours old
+				historicSummaries.removeIf(offerSummary -> offerSummary.getTimestamp() < tooOldTimestamp);
+			}
+		}
+
+		// Notify sessions
+		for (Session session : getSessions())
+			sendOfferSummaries(session, crossChainOfferSummaries);
+	}
+
+	@OnWebSocketConnect
+	@Override
+	public void onWebSocketConnect(Session session) {
+		Map<String, List<String>> queryParams = session.getUpgradeRequest().getParameterMap();
+		final boolean includeHistoric = queryParams.get("includeHistoric") != null;
+
+		List<CrossChainOfferSummary> crossChainOfferSummaries;
+
+		synchronized (currentSummaries) {
+			crossChainOfferSummaries = new ArrayList<>(currentSummaries);
+		}
+
+		if (includeHistoric)
+			synchronized (historicSummaries) {
+				crossChainOfferSummaries.addAll(historicSummaries);
+			}
+
+		if (!sendOfferSummaries(session, crossChainOfferSummaries)) {
+			session.close(4002, "websocket issue");
+			return;
+		}
+
+		super.onWebSocketConnect(session);
+	}
+
+	@OnWebSocketClose
+	@Override
+	public void onWebSocketClose(Session session, int statusCode, String reason) {
+		super.onWebSocketClose(session, statusCode, reason);
+	}
+
+	@OnWebSocketMessage
+	public void onWebSocketMessage(Session session, String message) {
+		/* ignored */
 	}
 
 	private boolean sendOfferSummaries(Session session, List<CrossChainOfferSummary> crossChainOfferSummaries) {
@@ -186,6 +177,68 @@ public class TradeOffersWebSocket extends ApiWebSocket {
 		return true;
 	}
 
+	private static void populateCurrentSummaries(Repository repository) throws DataException {
+		// We want ALL OFFERING trades
+		Boolean isFinished = Boolean.FALSE;
+		Integer dataByteOffset = BTCACCT.MODE_BYTE_OFFSET;
+		Long expectedValue = (long) BTCACCT.Mode.OFFERING.value;
+		Integer minimumFinalHeight = null;
+
+		List<ATStateData> initialAtStates = repository.getATRepository().getMatchingFinalATStates(BTCACCT.CODE_BYTES_HASH,
+				isFinished, dataByteOffset, expectedValue, minimumFinalHeight,
+				null, null, null);
+
+		if (initialAtStates == null)
+			throw new DataException("Couldn't fetch current trades from repository");
+
+		// Save initial AT modes
+		previousAtModes.putAll(initialAtStates.stream().collect(Collectors.toMap(ATStateData::getATAddress, atState -> BTCACCT.Mode.OFFERING)));
+
+		// Convert to offer summaries
+		currentSummaries.addAll(produceSummaries(repository, initialAtStates, null));
+	}
+
+	private static void populateHistoricSummaries(Repository repository) throws DataException {
+		// We want REDEEMED/REFUNDED/CANCELLED trades over the last 24 hours
+		long timestamp = System.currentTimeMillis() - 24 * 60 * 60 * 1000L;
+		int minimumFinalHeight = repository.getBlockRepository().getHeightFromTimestamp(timestamp);
+
+		if (minimumFinalHeight == 0)
+			throw new DataException("Couldn't fetch block timestamp from repository");
+
+		Boolean isFinished = Boolean.TRUE;
+		Integer dataByteOffset = null;
+		Long expectedValue = null;
+		++minimumFinalHeight; // because height is just *before* timestamp
+
+		List<ATStateData> historicAtStates = repository.getATRepository().getMatchingFinalATStates(BTCACCT.CODE_BYTES_HASH,
+				isFinished, dataByteOffset, expectedValue, minimumFinalHeight,
+				null, null, null);
+
+		if (historicAtStates == null)
+			throw new DataException("Couldn't fetch historic trades from repository");
+
+		for (ATStateData historicAtState : historicAtStates) {
+			CrossChainOfferSummary historicOfferSummary = produceSummary(repository, historicAtState, null);
+
+			switch (historicOfferSummary.getMode()) {
+				case REDEEMED:
+				case REFUNDED:
+				case CANCELLED:
+					break;
+
+				default:
+					continue;
+			}
+
+			// Add summary to initial burst
+			historicSummaries.add(historicOfferSummary);
+
+			// Save initial AT mode
+			previousAtModes.put(historicAtState.getATAddress(), historicOfferSummary.getMode());
+		}
+	}
+
 	private static CrossChainOfferSummary produceSummary(Repository repository, ATStateData atState, Long timestamp) throws DataException {
 		CrossChainTradeData crossChainTradeData = BTCACCT.populateTradeData(repository, atState);
 

src/main/java/org/qortal/controller/BlockNotifier.java

@@ -1,61 +0,0 @@
-package org.qortal.controller;
-
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.Map;
-
-import org.eclipse.jetty.websocket.api.Session;
-import org.qortal.api.model.BlockInfo;
-import org.qortal.data.block.BlockData;
-
-public class BlockNotifier {
-
-	private static BlockNotifier instance;
-
-	@FunctionalInterface
-	public interface Listener {
-		void notify(BlockInfo blockInfo);
-	}
-
-	private Map<Session, Listener> listenersBySession = new HashMap<>();
-
-	private BlockNotifier() {
-	}
-
-	public static synchronized BlockNotifier getInstance() {
-		if (instance == null)
-			instance = new BlockNotifier();
-
-		return instance;
-	}
-
-	public void register(Session session, Listener listener) {
-		synchronized (this.listenersBySession) {
-			this.listenersBySession.put(session, listener);
-		}
-	}
-
-	public void deregister(Session session) {
-		synchronized (this.listenersBySession) {
-			this.listenersBySession.remove(session);
-		}
-	}
-
-	public void onNewBlock(BlockData blockData) {
-		// Convert BlockData to BlockInfo
-		BlockInfo blockInfo = new BlockInfo(blockData);
-
-		for (Listener listener : getAllListeners())
-			listener.notify(blockInfo);
-	}
-
-	private Collection<Listener> getAllListeners() {
-		// Make a copy of listeners to both avoid concurrent modification
-		// and reduce synchronization time
-		synchronized (this.listenersBySession) {
-			return new ArrayList<>(this.listenersBySession.values());
-		}
-	}
-
-}

src/main/java/org/qortal/controller/Controller.java

@@ -50,6 +50,8 @@ import org.qortal.data.network.PeerData;
 import org.qortal.data.transaction.ArbitraryTransactionData;
 import org.qortal.data.transaction.TransactionData;
 import org.qortal.data.transaction.ArbitraryTransactionData.DataType;
+import org.qortal.event.Event;
+import org.qortal.event.EventBus;
 import org.qortal.data.transaction.ChatTransactionData;
 import org.qortal.globalization.Translator;
 import org.qortal.gui.Gui;
@@ -629,6 +631,11 @@ public class Controller extends Thread {
 		}
 	}
 
+	public static class StatusChangeEvent implements Event {
+		public StatusChangeEvent() {
+		}
+	}
+
 	private void updateSysTray() {
 		if (NTP.getTime() == null) {
 			SysTray.getInstance().setToolTipText(Translator.INSTANCE.translate("SysTray", "SYNCHRONIZING_CLOCK"));
@@ -656,7 +663,7 @@ public class Controller extends Thread {
 		SysTray.getInstance().setToolTipText(tooltip);
 
 		this.callbackExecutor.execute(() -> {
-			StatusNotifier.getInstance().onStatusChange(NTP.getTime());
+			EventBus.INSTANCE.notify(new StatusChangeEvent());
 		});
 	}
 
@@ -783,6 +790,18 @@ public class Controller extends Thread {
 		requestSysTrayUpdate = true;
 	}
 
+	public static class NewBlockEvent implements Event {
+		private final BlockData blockData;
+
+		public NewBlockEvent(BlockData blockData) {
+			this.blockData = blockData;
+		}
+
+		public BlockData getBlockData() {
+			return this.blockData;
+		}
+	}
+
 	public void onNewBlock(BlockData latestBlockData) {
 		this.setChainTip(latestBlockData);
 		requestSysTrayUpdate = true;
@@ -792,7 +811,8 @@ public class Controller extends Thread {
 			Network network = Network.getInstance();
 			network.broadcast(peer -> network.buildHeightMessage(peer, latestBlockData));
 
-			BlockNotifier.getInstance().onNewBlock(latestBlockData);
+			// Notify listeners of new block
+			EventBus.INSTANCE.notify(new NewBlockEvent(latestBlockData));
 
 			if (this.notifyGroupMembershipChange) {
 				this.notifyGroupMembershipChange = false;

src/main/java/org/qortal/controller/StatusNotifier.java

@@ -1,56 +0,0 @@
-package org.qortal.controller;
-
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.Map;
-
-import org.eclipse.jetty.websocket.api.Session;
-
-public class StatusNotifier {
-
-	private static StatusNotifier instance;
-
-	@FunctionalInterface
-	public interface Listener {
-		void notify(long timestamp);
-	}
-
-	private Map<Session, Listener> listenersBySession = new HashMap<>();
-
-	private StatusNotifier() {
-	}
-
-	public static synchronized StatusNotifier getInstance() {
-		if (instance == null)
-			instance = new StatusNotifier();
-
-		return instance;
-	}
-
-	public void register(Session session, Listener listener) {
-		synchronized (this.listenersBySession) {
-			this.listenersBySession.put(session, listener);
-		}
-	}
-
-	public void deregister(Session session) {
-		synchronized (this.listenersBySession) {
-			this.listenersBySession.remove(session);
-		}
-	}
-
-	public void onStatusChange(long now) {
-		for (Listener listener : getAllListeners())
-			listener.notify(now);
-	}
-
-	private Collection<Listener> getAllListeners() {
-		// Make a copy of listeners to both avoid concurrent modification
-		// and reduce synchronization time
-		synchronized (this.listenersBySession) {
-			return new ArrayList<>(this.listenersBySession.values());
-		}
-	}
-
-}