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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.shiro.event;
20  
21  import java.lang.annotation.ElementType;
22  import java.lang.annotation.Retention;
23  import java.lang.annotation.RetentionPolicy;
24  import java.lang.annotation.Target;
25  
26  /**
27   * Indicates a method is an event consumer.  The method must have a single argument and the argument's type determines
28   * what type of events should be delivered to the method for consumption.
29   * <p/>
30   * For example:
31   * <pre>
32   * &#64;Subscribe
33   * public void onSomeEvent(SomeEvent event) { ... }
34   * </pre>
35   * <p/>
36   * Because the method argument is declared as a {@code SomeEvent} type, the method will be called by the event
37   * dispatcher whenever a {@code SomeEvent} instance (or one of its subclass instances that is not already registered)
38   * is published.
39   *
40   * @since 1.3
41   */
42  @Retention(value = RetentionPolicy.RUNTIME)
43  @Target(value = ElementType.METHOD)
44  public @interface Subscribe {
45  }