hazelcast-master/hazelcast/src/main/java/com/hazelcast/map/impl/MapSplitBrainProtectionAwareService.java
/*
 * Copyright (c) 2008-2023, Hazelcast, Inc. All Rights Reserved.
 *
 * 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 com.hazelcast.map.impl;

import com.hazelcast.internal.services.SplitBrainProtectionAwareService;
import com.hazelcast.internal.util.ConstructorFunction;
import com.hazelcast.internal.util.ContextMutexFactory;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

import static com.hazelcast.internal.util.ConcurrencyUtil.getOrPutSynchronized;

/**
 * Split brain protection service will ask map service about whether map has defined split brain protection or not.
 */
public class MapSplitBrainProtectionAwareService implements SplitBrainProtectionAwareService {

    private static final Object NULL_OBJECT = new Object();

    private final MapServiceContext mapServiceContext;

    private final ConcurrentMap<String, Object> splitBrainProtectionConfigCache = new ConcurrentHashMap<>();
    private final ContextMutexFactory splitBrainProtectionConfigCacheMutexFactory = new ContextMutexFactory();
    private final ConstructorFunction<String, Object> splitBrainProtectionConfigConstructor =
            new ConstructorFunction<String, Object>() {
        @Override
        public Object createNew(String name) {
            MapContainer mapContainer = mapServiceContext.getMapContainer(name);
            String splitBrainProtectionName = mapContainer.getSplitBrainProtectionName();
            return splitBrainProtectionName == null ? NULL_OBJECT : splitBrainProtectionName;
        }
    };

    public MapSplitBrainProtectionAwareService(MapServiceContext mapServiceContext) {
        this.mapServiceContext = mapServiceContext;
    }

    @Override
    public String getSplitBrainProtectionName(String name) {
        Object splitBrainProtectionName = getOrPutSynchronized(splitBrainProtectionConfigCache, name,
                splitBrainProtectionConfigCacheMutexFactory, splitBrainProtectionConfigConstructor);
        return splitBrainProtectionName == NULL_OBJECT ? null : (String) splitBrainProtectionName;
    }

    public void onDestroy(String name) {
        splitBrainProtectionConfigCache.remove(name);
    }
}
