Package: MessageBus

MessageBus

Coverage

1: /*
2: * *********************************************************************************************************************
3: *
4: * TheseFoolishThings: Miscellaneous utilities
5: * http://tidalwave.it/projects/thesefoolishthings
6: *
7: * Copyright (C) 2009 - 2023 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
12: * the License. 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
17: * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
18: * specific language governing permissions and limitations under the License.
19: *
20: * *********************************************************************************************************************
21: *
22: * git clone https://bitbucket.org/tidalwave/thesefoolishthings-src
23: * git clone https://github.com/tidalwave-it/thesefoolishthings-src
24: *
25: * *********************************************************************************************************************
26: */
27: package it.tidalwave.messagebus;
28:
29: import javax.annotation.Nonnull;
30:
31: /***********************************************************************************************************************
32: *
33: * A simple message bus for a local publish/subscribe facility.
34: *
35: * @author Fabrizio Giudici
36: *
37: **********************************************************************************************************************/
38: public interface MessageBus
39: {
40: /*******************************************************************************************************************
41: *
42: * A listener to receive notifications from a {@link MessageBus}.
43: *
44: * @stereotype Listener
45: *
46: ******************************************************************************************************************/
47: public static interface Listener<TOPIC>
48: {
49: /***************************************************************************************************************
50: *
51: * Notifies the reception of the given message.
52: *
53: * @param message the event
54: *
55: **************************************************************************************************************/
56: public void notify (@Nonnull TOPIC message);
57: }
58:
59: /*******************************************************************************************************************
60: *
61: * Publishes the given event. The topic is the class of the event.
62: *
63: * @param <TOPIC> the static type of the topic
64: * @param message the event
65: *
66: ******************************************************************************************************************/
67: public <TOPIC> void publish (@Nonnull TOPIC message);
68:
69: /*******************************************************************************************************************
70: *
71: * Publishes the given message and topic. Passing an explicit topic can be useful when dealing with a hierarchy of
72: * events (so, perhaps a subclass is passed but the topic is the root of the hierarchy).
73: *
74: * @param <TOPIC> the static type of the topic
75: * @param topic the topic
76: * @param message the message
77: *
78: ******************************************************************************************************************/
79: public <TOPIC> void publish (@Nonnull Class<TOPIC> topic, @Nonnull TOPIC message);
80:
81: /*******************************************************************************************************************
82: *
83: * Subscribes a {@link Listener} to a topic.
84: *
85: * @param <TOPIC> the static type of the topic
86: * @param topic the topic
87: * @param listener the listener
88: *
89: ******************************************************************************************************************/
90: public <TOPIC> void subscribe (@Nonnull Class<TOPIC> topic, @Nonnull Listener<TOPIC> listener);
91:
92: /*******************************************************************************************************************
93: *
94: * Unsubscribes a {@link Listener}.
95: *
96: * @param listener the listener
97: *
98: ******************************************************************************************************************/
99: public void unsubscribe (@Nonnull Listener<?> listener);
100: }