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.schedule;
28
29 import java.util.concurrent.ConcurrentHashMap;
30 import java.util.concurrent.ConcurrentMap;
31 import java.util.concurrent.atomic.AtomicInteger;
32
33 import org.apache.hc.core5.annotation.Contract;
34 import org.apache.hc.core5.annotation.ThreadingBehavior;
35 import org.apache.hc.core5.util.Args;
36
37 /**
38 * Concurrent map of integer counts.
39 *
40 * @since 5.0
41 *
42 * @param <T> identifier used as a map key
43 */
44 @Contract(threading = ThreadingBehavior.SAFE)
45 public final class ConcurrentCountMap<T> {
46
47 private final ConcurrentMap<T, AtomicInteger> map;
48
49 public ConcurrentCountMap() {
50 this.map = new ConcurrentHashMap<>();
51 }
52
53 public int getCount(final T identifier) {
54 Args.notNull(identifier, "Identifier");
55 final AtomicInteger count = map.get(identifier);
56 return count != null ? count.get() : 0;
57 }
58
59 public void resetCount(final T identifier) {
60 Args.notNull(identifier, "Identifier");
61 map.remove(identifier);
62 }
63
64 public int increaseCount(final T identifier) {
65 Args.notNull(identifier, "Identifier");
66 final AtomicInteger count = get(identifier);
67 return count.incrementAndGet();
68 }
69
70 private AtomicInteger get(final T identifier) {
71 AtomicInteger entry = map.get(identifier);
72 if (entry == null) {
73 final AtomicInteger newEntry = new AtomicInteger();
74 entry = map.putIfAbsent(identifier, newEntry);
75 if (entry == null) {
76 entry = newEntry;
77 }
78 }
79 return entry;
80 }
81
82 }