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;
  
  import com.googlecode.concurrentlinkedhashmap.ConcurrentLinkedHashMap;
  import com.googlecode.concurrentlinkedhashmap.Weighers;
  
  /**
   * A {@link ConcurrentLinkedHashMap} wrapper for the universal {@link CacheMap}.
   *
   * @author Eric Zhao
   * @since 0.2.0
   */
  public class ConcurrentLinkedHashMapWrapper<T, R> implements CacheMap<T, R> {
  
      private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
  
      private final ConcurrentLinkedHashMap<T, R> map;
  
      public ConcurrentLinkedHashMapWrapper(long size) {
          if (size <= 0) {
              throw new IllegalArgumentException("Cache max capacity should be positive: " + size);
          }
          this.map = new ConcurrentLinkedHashMap.Builder<T, R>()
              .concurrencyLevel(DEFAULT_CONCURRENCY_LEVEL)
              .maximumWeightedCapacity(size)
              .weigher(Weighers.singleton())
              .build();
      }
  
      public ConcurrentLinkedHashMapWrapper(ConcurrentLinkedHashMap<T, R> map) {
          if (map == null) {
              throw new IllegalArgumentException("Invalid map instance");
          }
          this.map = map;
      }
  
      @Override
      public boolean containsKey(T key) {
          return map.containsKey(key);
      }
  
      @Override
      public R get(T key) {
          return map.get(key);
      }
  
      @Override
      public R remove(T key) {
          return map.remove(key);
      }
  
      @Override
      public R put(T key, R value) {
          return map.put(key, value);
      }
  
      @Override
      public R putIfAbsent(T key, R value) {
          return map.putIfAbsent(key, value);
      }
  
      @Override
      public long size() {
          return map.weightedSize();
      }
  
      @Override
      public void clear() {
          map.clear();
      }
  
      @Override
      public Set<T> keySet(boolean ascending) {
          if (ascending) {
              return map.ascendingKeySet();
          } else {
              return map.descendingKeySet();
          }
      }
  }
  