--- /dev/null
+/*
+ * Copyright (c) 2016 Cisco Systems, Inc. and others. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.netconf.impl.osgi;
+
+import com.google.common.base.Optional;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Collections2;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Sets;
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import org.opendaylight.controller.config.threadpool.ScheduledThreadPool;
+import org.opendaylight.netconf.api.monitoring.NetconfManagementSession;
+import org.opendaylight.netconf.api.monitoring.NetconfMonitoringService;
+import org.opendaylight.netconf.api.monitoring.SessionEvent;
+import org.opendaylight.netconf.api.monitoring.SessionListener;
+import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.monitoring.rev101004.netconf.state.Sessions;
+import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.monitoring.rev101004.netconf.state.SessionsBuilder;
+import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.netconf.monitoring.rev101004.netconf.state.sessions.Session;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This class implements {@link SessionListener} to receive updates about Netconf sessions. Instance notifies its
+ * listeners
+ * about session start and end. It also publishes on regular interval list of sessions,
+ * where events like rpc or notification happened.
+ */
+class NetconfSessionMonitoringService implements SessionListener, AutoCloseable {
+
+ private static final Logger LOG = LoggerFactory.getLogger(NetconfSessionMonitoringService.class);
+
+ private final Set<NetconfManagementSession> sessions = Sets.newHashSet();
+ private final Set<NetconfManagementSession> changedSessions = Sets.newHashSet();
+ private final Set<NetconfMonitoringService.SessionsListener> listeners = Sets.newHashSet();
+ private final ScheduledExecutorService executor;
+ private final long updateInterval;
+ private boolean running;
+
+ /**
+ * Constructor for {@code NetconfSessionMonitoringService}.
+ *
+ * @param schedulingThreadPool thread pool for scheduling session stats updates. If not present, updates won't be
+ * scheduled.
+ * @param updateInterval update interval. If is less than 0, updates won't be scheduled
+ */
+ NetconfSessionMonitoringService(Optional<ScheduledThreadPool> schedulingThreadPool, long updateInterval) {
+ this.updateInterval = updateInterval;
+ if (schedulingThreadPool.isPresent() && updateInterval > 0) {
+ this.executor = schedulingThreadPool.get().getExecutor();
+ LOG.info("/netconf-state/sessions will be updated every {} seconds.", updateInterval);
+ } else {
+ LOG.info("Scheduling thread pool is present = {}, "
+ + "update interval {}: /netconf-state/sessions won't be updated.",
+ schedulingThreadPool.isPresent(), updateInterval);
+ this.executor = null;
+ }
+ }
+
+ synchronized Sessions getSessions() {
+ final Collection<Session> managementSessions = Collections2.transform(sessions,
+ NetconfManagementSession::toManagementSession);
+ return new SessionsBuilder().setSession(ImmutableList.copyOf(managementSessions)).build();
+ }
+
+ @Override
+ public synchronized void onSessionUp(final NetconfManagementSession session) {
+ LOG.debug("Session {} up", session);
+ Preconditions.checkState(!sessions.contains(session), "Session %s was already added", session);
+ sessions.add(session);
+ notifySessionUp(session);
+ }
+
+ @Override
+ public synchronized void onSessionDown(final NetconfManagementSession session) {
+ LOG.debug("Session {} down", session);
+ Preconditions.checkState(sessions.contains(session), "Session %s not present", session);
+ sessions.remove(session);
+ changedSessions.remove(session);
+ notifySessionDown(session);
+ }
+
+ @Override
+ public synchronized void onSessionEvent(SessionEvent event) {
+ changedSessions.add(event.getSession());
+ }
+
+ synchronized AutoCloseable registerListener(final NetconfMonitoringService.SessionsListener listener) {
+ listeners.add(listener);
+ if (!running) {
+ startUpdateSessionStats();
+ }
+ return () -> listeners.remove(listener);
+ }
+
+ @Override
+ public synchronized void close() {
+ stopUpdateSessionStats();
+ listeners.clear();
+ sessions.clear();
+ }
+
+ private synchronized void updateSessionStats() {
+ if (changedSessions.isEmpty()) {
+ return;
+ }
+ final List<Session> changed = changedSessions.stream()
+ .map(NetconfManagementSession::toManagementSession)
+ .collect(Collectors.toList());
+ final ImmutableList<Session> sessionImmutableList = ImmutableList.copyOf(changed);
+ for (NetconfMonitoringService.SessionsListener listener : listeners) {
+ listener.onSessionsUpdated(sessionImmutableList);
+ }
+ changedSessions.clear();
+ }
+
+ private void notifySessionUp(NetconfManagementSession managementSession) {
+ Session session = managementSession.toManagementSession();
+ for (NetconfMonitoringService.SessionsListener listener : listeners) {
+ listener.onSessionStarted(session);
+ }
+ }
+
+ private void notifySessionDown(NetconfManagementSession managementSession) {
+ Session session = managementSession.toManagementSession();
+ for (NetconfMonitoringService.SessionsListener listener : listeners) {
+ listener.onSessionEnded(session);
+ }
+ }
+
+ private void startUpdateSessionStats() {
+ if (executor != null) {
+ executor.scheduleAtFixedRate(this::updateSessionStats, 1, updateInterval, TimeUnit.SECONDS);
+ running = true;
+ }
+ }
+
+ private void stopUpdateSessionStats() {
+ if (executor != null) {
+ executor.shutdownNow();
+ running = false;
+ }
+ }
+}