1 package org.eclipse.aether;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import static java.util.Objects.requireNonNull;
23
24 import java.util.concurrent.ConcurrentHashMap;
25 import java.util.concurrent.ConcurrentMap;
26
27 /**
28 * A simple session data storage backed by a thread-safe map.
29 */
30 public final class DefaultSessionData
31 implements SessionData
32 {
33
34 private final ConcurrentMap<Object, Object> data;
35
36 public DefaultSessionData()
37 {
38 data = new ConcurrentHashMap<>();
39 }
40
41 public void set( Object key, Object value )
42 {
43 requireNonNull( key, "key cannot be null" );
44
45 if ( value != null )
46 {
47 data.put( key, value );
48 }
49 else
50 {
51 data.remove( key );
52 }
53 }
54
55 public boolean set( Object key, Object oldValue, Object newValue )
56 {
57 requireNonNull( key, "key cannot be null" );
58
59 if ( newValue != null )
60 {
61 if ( oldValue == null )
62 {
63 return data.putIfAbsent( key, newValue ) == null;
64 }
65 return data.replace( key, oldValue, newValue );
66 }
67 else
68 {
69 if ( oldValue == null )
70 {
71 return !data.containsKey( key );
72 }
73 return data.remove( key, oldValue );
74 }
75 }
76
77 public Object get( Object key )
78 {
79 requireNonNull( key, "key cannot be null" );
80
81 return data.get( key );
82 }
83
84 }