001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel.impl.ha;
018
019import java.util.ArrayList;
020import java.util.List;
021import java.util.Optional;
022import java.util.concurrent.locks.StampedLock;
023import java.util.function.Consumer;
024
025import org.apache.camel.CamelContext;
026import org.apache.camel.ha.CamelClusterEventListener;
027import org.apache.camel.ha.CamelClusterMember;
028import org.apache.camel.ha.CamelClusterService;
029import org.apache.camel.ha.CamelClusterView;
030import org.apache.camel.support.ServiceSupport;
031import org.apache.camel.util.concurrent.LockHelper;
032
033public abstract class AbstractCamelClusterView extends ServiceSupport implements CamelClusterView {
034    private final CamelClusterService clusterService;
035    private final String namespace;
036    private final List<CamelClusterEventListener> listeners;
037    private final StampedLock lock;
038    private CamelContext camelContext;
039
040    protected AbstractCamelClusterView(CamelClusterService cluster, String namespace) {
041        this.clusterService = cluster;
042        this.namespace = namespace;
043        this.listeners = new ArrayList<>();
044        this.lock = new StampedLock();
045    }
046
047    @Override
048    public void setCamelContext(CamelContext camelContext) {
049        this.camelContext = camelContext;
050    }
051
052    @Override
053    public CamelContext getCamelContext() {
054        return camelContext;
055    }
056
057    @Override
058    public CamelClusterService getClusterService() {
059        return this.clusterService;
060    }
061
062    @Override
063    public String getNamespace() {
064        return this.namespace;
065    }
066
067    @Override
068    public void addEventListener(CamelClusterEventListener listener) {
069        LockHelper.doWithWriteLock(lock, () -> listeners.add(listener));
070    }
071
072    @Override
073    public void removeEventListener(CamelClusterEventListener listener) {
074        LockHelper.doWithWriteLock(lock, () -> listeners.removeIf(l -> l == listener));
075    }
076
077    // **************************************
078    // Events
079    // **************************************
080
081    private <T extends CamelClusterEventListener> void doWithListener(Class<T> type, Consumer<T> consumer) {
082        LockHelper.doWithReadLock(
083            lock,
084            () -> {
085                for (int i = 0; i < listeners.size(); i++) {
086                    CamelClusterEventListener listener = listeners.get(0);
087
088                    if (type.isInstance(listener)) {
089                        consumer.accept(type.cast(listener));
090                    }
091                }
092            }
093        );
094    }
095
096    protected void fireLeadershipChangedEvent(Optional<CamelClusterMember> leader) {
097        doWithListener(
098            CamelClusterEventListener.Leadership.class,
099            listener -> listener.leadershipChanged(this, leader)
100        );
101    }
102
103    protected void fireMemberAddedEvent(CamelClusterMember member) {
104        doWithListener(
105            CamelClusterEventListener.Membership.class,
106            listener -> listener.memberAdded(this, member)
107        );
108    }
109
110    protected void fireMemberRemovedEvent(CamelClusterMember member) {
111        doWithListener(
112            CamelClusterEventListener.Membership.class,
113            listener -> listener.memberRemoved(this, member)
114        );
115    }
116}