001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.shiro.event;
020
021import java.lang.annotation.Documented;
022import java.lang.annotation.ElementType;
023import java.lang.annotation.Retention;
024import java.lang.annotation.RetentionPolicy;
025import java.lang.annotation.Target;
026
027/**
028 * Indicates a method is an event consumer.  The method must have a single argument and the argument's type determines
029 * what type of events should be delivered to the method for consumption.
030 * <p/>
031 * For example:
032 * <pre>
033 * &#64;Subscribe
034 * public void onSomeEvent(SomeEvent event) { ... }
035 * </pre>
036 * <p/>
037 * Because the method argument is declared as a {@code SomeEvent} type, the method will be called by the event
038 * dispatcher whenever a {@code SomeEvent} instance (or one of its subclass instances that is not already registered)
039 * is published.
040 *
041 * @since 1.3
042 */
043@Retention(value = RetentionPolicy.RUNTIME)
044@Target(value = ElementType.METHOD)
045@Documented
046public @interface Subscribe {
047}