1 /*
2 * *************************************************************************************************************************************************************
3 *
4 * TheseFoolishThings: Miscellaneous utilities
5 * http://tidalwave.it/projects/thesefoolishthings
6 *
7 * Copyright (C) 2009 - 2026 by Tidalwave s.a.s. (http://tidalwave.it)
8 *
9 * *************************************************************************************************************************************************************
10 *
11 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
12 * You may obtain a copy of the License at
13 *
14 * http://www.apache.org/licenses/LICENSE-2.0
15 *
16 * 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
17 * CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
18 *
19 * *************************************************************************************************************************************************************
20 *
21 * git clone https://bitbucket.org/tidalwave/thesefoolishthings-src
22 * git clone https://github.com/tidalwave-it/thesefoolishthings-src
23 *
24 * *************************************************************************************************************************************************************
25 */
26 package it.tidalwave.messagebus.impl.spring;
27
28 import java.lang.reflect.Method;
29 import jakarta.annotation.Nonnull;
30 import it.tidalwave.util.annotation.VisibleForTesting;
31 import it.tidalwave.messagebus.MessageBus;
32 import it.tidalwave.messagebus.MessageBusHelper;
33 import it.tidalwave.messagebus.MessageBusHelper.MethodAdapter;
34 import lombok.Getter;
35 import lombok.RequiredArgsConstructor;
36 import lombok.ToString;
37 import lombok.extern.slf4j.Slf4j;
38
39 /***************************************************************************************************************************************************************
40 * An implementation of {@link MessageBusHelper.Adapter} that subscribes listener methods to a given {@link MessageBus}.
41 * @author Fabrizio Giudici
42 **************************************************************************************************************************************************************/
43 @RequiredArgsConstructor @Slf4j
44 public class MessageBusAdapterFactory implements MessageBusHelper.Adapter
45 {
46 /** The message bus. */
47 @Nonnull
48 private final MessageBus messageBus;
49
50 /***********************************************************************************************************************************************************
51 * A listener that delivers messages to a method of an object, and that can subscribe and unsubscribe itself.
52 * @param <T> the static type of the topic
53 **********************************************************************************************************************************************************/
54 @Getter @VisibleForTesting @ToString(of = "method")
55 class MessageBusListenerAdapter<T> implements MethodAdapter<T>, MessageBus.Listener<T>
56 {
57 @Nonnull
58 private final Object owner;
59
60 @Nonnull
61 private final Method method;
62
63 @Nonnull
64 private final Class<T> topic;
65
66 /*******************************************************************************************************************************************************
67 * Creates a new instance.
68 * @param owner the object that owns the method
69 * @param method the listener method
70 * @param topic the topic
71 ******************************************************************************************************************************************************/
72 public MessageBusListenerAdapter (@Nonnull final Object owner,
73 @Nonnull final Method method,
74 @Nonnull final Class<T> topic)
75 {
76 this.owner = owner;
77 this.method = method;
78 this.topic = topic;
79 method.setAccessible(true);
80 }
81
82 /*******************************************************************************************************************************************************
83 * {@inheritDoc} Exceptions thrown by the listener method are logged.
84 ******************************************************************************************************************************************************/
85 @Override
86 public void notify (@Nonnull final T message)
87 {
88 log.trace("notify({})", message);
89
90 try
91 {
92 method.invoke(owner, message);
93 }
94 catch (Throwable t)
95 {
96 log.error("Error calling {} with {}", method, message.getClass());
97 log.error("", t);
98 }
99 }
100
101 /*******************************************************************************************************************************************************
102 * {@inheritDoc}
103 ******************************************************************************************************************************************************/
104 @Override
105 public void subscribe()
106 {
107 messageBus.subscribe(topic, this);
108 }
109
110 /*******************************************************************************************************************************************************
111 * {@inheritDoc}
112 ******************************************************************************************************************************************************/
113 @Override
114 public void unsubscribe()
115 {
116 messageBus.unsubscribe(this);
117 }
118 }
119
120 /***********************************************************************************************************************************************************
121 * {@inheritDoc}
122 **********************************************************************************************************************************************************/
123 @Override @Nonnull
124 public <T> MethodAdapter<T> createMethodAdapter (@Nonnull final Object owner,
125 @Nonnull final Method method,
126 @Nonnull final Class<T> topic)
127 {
128 return new MessageBusListenerAdapter<>(owner, method, topic);
129 }
130
131 /***********************************************************************************************************************************************************
132 * {@inheritDoc}
133 **********************************************************************************************************************************************************/
134 @Override
135 public void publish (@Nonnull final Object message)
136 {
137 messageBus.publish(message);
138 }
139
140 /***********************************************************************************************************************************************************
141 * {@inheritDoc}
142 **********************************************************************************************************************************************************/
143 @Override
144 public <T> void publish (@Nonnull final Class<T> topic, @Nonnull final T message)
145 {
146 messageBus.publish(topic, message);
147 }
148 }