core/store/dist/src/main/java/org/onosproject/store/flow/impl/ReplicaInfoManager.java

/*
 * Copyright 2014 Open Networking Laboratory
 *
 * 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 org.onosproject.store.flow.impl;

import static com.google.common.base.Preconditions.checkNotNull;
import static org.slf4j.LoggerFactory.getLogger;
import static org.onosproject.store.flow.ReplicaInfoEvent.Type.MASTER_CHANGED;
import static org.onosproject.store.flow.ReplicaInfoEvent.Type.BACKUPS_CHANGED;

import java.util.Collections;
import java.util.List;
import java.util.Map;

import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Deactivate;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.ReferenceCardinality;
import org.apache.felix.scr.annotations.Service;
import org.onosproject.cluster.NodeId;
import org.onosproject.cluster.RoleInfo;
import org.onosproject.event.AbstractListenerRegistry;
import org.onosproject.event.EventDeliveryService;
import org.onosproject.mastership.MastershipEvent;
import org.onosproject.mastership.MastershipListener;
import org.onosproject.mastership.MastershipService;
import org.onosproject.net.DeviceId;
import org.onosproject.store.flow.ReplicaInfo;
import org.onosproject.store.flow.ReplicaInfoEvent;
import org.onosproject.store.flow.ReplicaInfoEventListener;
import org.onosproject.store.flow.ReplicaInfoService;
import org.slf4j.Logger;

import com.google.common.base.Objects;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Maps;

/**
 * Manages replica placement information.
 */
@Component(immediate = true)
@Service
public class ReplicaInfoManager implements ReplicaInfoService {

    private final Logger log = getLogger(getClass());

    private final MastershipListener mastershipListener = new InternalMastershipListener();

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected EventDeliveryService eventDispatcher;

    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
    protected MastershipService mastershipService;

    protected final AbstractListenerRegistry<ReplicaInfoEvent, ReplicaInfoEventListener>
        listenerRegistry = new AbstractListenerRegistry<>();

    private final Map<DeviceId, ReplicaInfo> deviceReplicaInfoMap = Maps.newConcurrentMap();

    @Activate
    public void activate() {
        eventDispatcher.addSink(ReplicaInfoEvent.class, listenerRegistry);
        mastershipService.addListener(mastershipListener);
        log.info("Started");
    }

    @Deactivate
    public void deactivate() {
        eventDispatcher.removeSink(ReplicaInfoEvent.class);
        mastershipService.removeListener(mastershipListener);
        log.info("Stopped");
    }

    @Override
    public ReplicaInfo getReplicaInfoFor(DeviceId deviceId) {
        return deviceReplicaInfoMap.computeIfAbsent(
                    deviceId,
                    id -> buildFromRoleInfo(mastershipService.getNodesFor(deviceId)));
    }

    @Override
    public void addListener(ReplicaInfoEventListener listener) {
        listenerRegistry.addListener(checkNotNull(listener));
    }

    @Override
    public void removeListener(ReplicaInfoEventListener listener) {
        listenerRegistry.removeListener(checkNotNull(listener));
    }

    private static ReplicaInfo buildFromRoleInfo(RoleInfo roles) {
        List<NodeId> backups = roles.backups() == null ?
                Collections.emptyList() : ImmutableList.copyOf(roles.backups());
        return new ReplicaInfo(roles.master(), backups);
    }

    final class InternalMastershipListener implements MastershipListener {

        @Override
        public void event(MastershipEvent event) {
            final DeviceId deviceId = event.subject();
            final ReplicaInfo replicaInfo = buildFromRoleInfo(event.roleInfo());
            ReplicaInfo oldReplicaInfo = deviceReplicaInfoMap.put(deviceId, replicaInfo);
            if (Objects.equal(oldReplicaInfo, replicaInfo)) {
                return;
            }
            switch (event.type()) {
            case MASTER_CHANGED:
                eventDispatcher.post(new ReplicaInfoEvent(MASTER_CHANGED,
                                                          event.subject(),
                                                          replicaInfo));
                break;
            case BACKUPS_CHANGED:
                eventDispatcher.post(new ReplicaInfoEvent(BACKUPS_CHANGED,
                                                          event.subject(),
                                                          replicaInfo));
                break;
            default:
                break;
            }
        }
    }

}