Java tutorial
/* * This file is part of LCMC written by Rasto Levrinc. * * Copyright (C) 2014, Rastislav Levrinc. * * The LCMC is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as published * by the Free Software Foundation; either version 2, or (at your option) * any later version. * * The LCMC is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with LCMC; see the file COPYING. If not, write to * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ package lcmc.cluster.service.storage; import com.google.common.base.Optional; import com.google.common.eventbus.Subscribe; import lcmc.ClusterEventBus; import lcmc.HwEventBus; import lcmc.cluster.domain.Cluster; import lcmc.common.domain.util.Tools; import lcmc.event.CommonMountPointsEvent; import lcmc.event.HwMountPointsChangedEvent; import lcmc.host.domain.Host; import javax.inject.Inject; import javax.inject.Named; import javax.inject.Singleton; import java.util.Collection; import java.util.Map; import java.util.Set; import java.util.TreeSet; import java.util.concurrent.ConcurrentHashMap; @Named @Singleton public class MountPointService { @Inject private HwEventBus hwEventBus; @Inject private ClusterEventBus clusterEventBus; private Map<Host, Set<String>> mountPointsByHost = new ConcurrentHashMap<Host, Set<String>>(); private Map<Cluster, Set<String>> commonMountPointsByCluster = new ConcurrentHashMap<Cluster, Set<String>>(); public void init() { hwEventBus.register(this); } @Subscribe public void mountPointsChanged(final HwMountPointsChangedEvent event) { mountPointsByHost.put(event.getHost(), event.getMountPoints()); updateCommonMountPoints(Optional.fromNullable(event.getHost().getCluster())); } public Set<String> getCommonMountPoints(final Cluster cluster) { final Set<String> mountPoints = commonMountPointsByCluster.get(cluster); if (mountPoints == null) { return new TreeSet<String>(); } return mountPoints; } private Set<String> getCommonMountPoints(final Collection<Host> hosts) { Optional<Set<String>> mountPointsIntersection = Optional.absent(); for (final Host host : hosts) { final Set<String> mountPoints = mountPointsByHost.get(host); mountPointsIntersection = Tools.getIntersection(Optional.fromNullable(mountPoints), mountPointsIntersection); } return mountPointsIntersection.or(new TreeSet<String>()); } private void updateCommonMountPoints(final Optional<Cluster> cluster) { if (!cluster.isPresent()) { return; } final Set<String> commonMountPoints = getCommonMountPoints(cluster.get().getHosts()); final Set<String> oldCommonMountPoints = commonMountPointsByCluster.get(cluster.get()); commonMountPointsByCluster.put(cluster.get(), commonMountPoints); if (oldCommonMountPoints == null || oldCommonMountPoints.isEmpty() || !Tools.equalCollections(commonMountPoints, oldCommonMountPoints)) { clusterEventBus.post(new CommonMountPointsEvent(cluster.get(), commonMountPoints)); } } }