001/*
002 * Copyright (C) 2007 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005 * in compliance with the License. You may obtain a copy of the License at
006 *
007 * http://www.apache.org/licenses/LICENSE-2.0
008 *
009 * Unless required by applicable law or agreed to in writing, software distributed under the License
010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
011 * or implied. See the License for the specific language governing permissions and limitations under
012 * the License.
013 */
014
015package com.google.common.eventbus;
016
017import com.google.common.annotations.Beta;
018import java.lang.annotation.ElementType;
019import java.lang.annotation.Retention;
020import java.lang.annotation.RetentionPolicy;
021import java.lang.annotation.Target;
022
023/**
024 * Marks a method as an event subscriber.
025 *
026 * <p>The type of event will be indicated by the method's first (and only) parameter. If this
027 * annotation is applied to methods with zero parameters, or more than one parameter, the object
028 * containing the method will not be able to register for event delivery from the {@link EventBus}.
029 *
030 * <p>Unless also annotated with @{@link AllowConcurrentEvents}, event subscriber methods will be
031 * invoked serially by each event bus that they are registered with.
032 *
033 * @author Cliff Biffle
034 * @since 10.0
035 */
036@Retention(RetentionPolicy.RUNTIME)
037@Target(ElementType.METHOD)
038@Beta
039public @interface Subscribe {}