content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * 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.alibaba.csp.sentinel.slots.statistic.cache;
  
  import java.util.Set;
  
  /**
   * A common cache map interface.
   *
   * @param <K> type of the key
   * @param <V> type of the value
   * @author Eric Zhao
   * @since 0.2.0
   */
  public interface CacheMap<K, V> {
  
      boolean containsKey(K key);
  
      V get(K key);
  
      V remove(K key);
  
      V put(K key, V value);
  
      V putIfAbsent(K key, V value);
  
      long size();
  
      void clear();
  
      Set<K> keySet(boolean ascending);
  }
  