oak-store-document/src/main/java/org/apache/jackrabbit/oak/plugins/document/util/MapFactory.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.jackrabbit.oak.plugins.document.util;

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

import org.apache.jackrabbit.oak.plugins.document.Path;
import org.apache.jackrabbit.oak.plugins.document.Revision;

/**
 * Experimental extension point for OAK-1772 to try out alternative approaches for persisting in memory state
 * Not part of API
 */
public abstract class MapFactory {
    private static MapFactory DEFAULT = new MapFactory() {
        @Override
        public ConcurrentMap<Path, Revision> create() {
            return new ConcurrentHashMap<>();
        }
    };

    public abstract ConcurrentMap<Path, Revision> create();

    private static MapFactory instance = DEFAULT;

    public static MapFactory getInstance(){
        return instance;
    }

    public static void setInstance(MapFactory instance) {
        MapFactory.instance = instance;
    }
}