content: /*
   * Copyright 2013-2023 the original author or authors.
   *
   * 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
   *
   *      https://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.alibaba.cloud.nacos.refresh;
  
  import java.util.Iterator;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * @author: ruansheng
   * @date: 2024-01-22
   */
  public final class NacosSnapshotConfigManager {
  
  	private NacosSnapshotConfigManager() {
  	}
  
  	private static final Logger log = LoggerFactory
  			.getLogger(NacosSnapshotConfigManager.class);
  
  	private static final Map<String, String> CONFIG_INFO_SNAPSHOT_MAP = new ConcurrentHashMap<>(
  			8);
  
  	private static final int MAX_SNAPSHOT_COUNT = 100;
  
  	private static String formatConfigSnapshotKey(String dataId, String group) {
  		return dataId + "@" + group;
  	}
  
  	public static String getAndRemoveConfigSnapshot(String dataId, String group) {
  		String configInfo = CONFIG_INFO_SNAPSHOT_MAP
  				.get(formatConfigSnapshotKey(dataId, group));
  		removeConfigSnapshot(dataId, group);
  		return configInfo;
  	}
  
  	public static void putConfigSnapshot(String dataId, String group, String configInfo) {
  		try {
  			// Theoretically, the capacity limit restriction will never be triggered.
  			// This portion of the code serves as an additional fault tolerance layer.
  			if (CONFIG_INFO_SNAPSHOT_MAP.size() > MAX_SNAPSHOT_COUNT) {
  				Iterator<Map.Entry<String, String>> iterator = CONFIG_INFO_SNAPSHOT_MAP
  						.entrySet().iterator();
  				iterator.next();
  				iterator.remove();
  			}
  			String snapshotKey = formatConfigSnapshotKey(dataId, group);
  			if (configInfo == null) {
  				CONFIG_INFO_SNAPSHOT_MAP.remove(snapshotKey);
  			}
  			else {
  				CONFIG_INFO_SNAPSHOT_MAP.put(snapshotKey, configInfo);
  			}
  		}
  		catch (Exception e) {
  			log.warn("remove nacos config snapshot error", e);
  		}
  	}
  
  	public static void removeConfigSnapshot(String dataId, String group) {
  		CONFIG_INFO_SNAPSHOT_MAP.remove(formatConfigSnapshotKey(dataId, group));
  	}
  
  }
  