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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  package org.apache.hc.client5.http.impl.cache;
28  
29  import java.util.LinkedHashMap;
30  import java.util.LinkedList;
31  import java.util.Map;
32  import java.util.Queue;
33  import java.util.function.Consumer;
34  
35  import org.apache.hc.client5.http.cache.HttpCacheEntry;
36  import org.apache.hc.client5.http.cache.HttpCacheStorageEntry;
37  import org.apache.hc.core5.annotation.Internal;
38  
39  @Internal
40  final public class InternalCacheStorage {
41  
42      private final Map<String, HttpCacheEntry> map;
43      private final Queue<HttpCacheStorageEntry> evictionQueue;
44      private final Consumer<HttpCacheStorageEntry> evictionCallback;
45  
46      public InternalCacheStorage(final int maxEntries, final Consumer<HttpCacheStorageEntry> evictionCallback) {
47          this.evictionCallback = evictionCallback;
48          this.map = new LinkedHashMap<String, HttpCacheEntry>(20, 0.75f, true) {
49  
50              @Override
51              protected boolean removeEldestEntry(final Map.Entry<String, HttpCacheEntry> eldest) {
52                  if (size() > maxEntries) {
53                      if (evictionCallback != null) {
54                          evictionQueue.add(new HttpCacheStorageEntry(eldest.getKey(), eldest.getValue()));
55                      }
56                      return true;
57                  }
58                  return false;
59              }
60  
61          };
62          this.evictionQueue = new LinkedList<>();
63      }
64  
65      public InternalCacheStorage(final int maxEntries) {
66          this(maxEntries, null);
67      }
68  
69      public InternalCacheStorage() {
70          this(Integer.MAX_VALUE, null);
71      }
72  
73      public void put(final String key, final HttpCacheEntry entry) {
74          map.put(key, entry);
75          HttpCacheStorageEntry evicted;
76          while ((evicted = evictionQueue.poll()) != null) {
77              if (evictionCallback != null) {
78                  evictionCallback.accept(evicted);
79              }
80          }
81      }
82  
83      public HttpCacheEntry get(final String key) {
84          return map.get(key);
85      }
86  
87      public HttpCacheEntry remove(final String key) {
88          return map.remove(key);
89      }
90  
91      public void clear() {
92          map.clear();
93      }
94  
95  }