001/*
002 * Copyright (C) 2007 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.eventbus;
018
019import com.google.common.annotations.Beta;
020
021import java.lang.annotation.ElementType;
022import java.lang.annotation.Retention;
023import java.lang.annotation.RetentionPolicy;
024import java.lang.annotation.Target;
025
026/**
027 * Marks a method as an event handler, as used by
028 * {@link AnnotatedHandlerFinder} and {@link EventBus}.
029 *
030 * <p>The type of event will be indicated by the method's first (and only)
031 * parameter.  If this annotation is applied to methods with zero parameters,
032 * or more than one parameter, the object containing the method will not be able
033 * to register for event delivery from the {@link EventBus}.
034 *
035 * <p>Unless also annotated with @{@link AllowConcurrentEvents}, event handler
036 * methods will be invoked serially by each event bus that they are registered
037 * with.
038 *
039 * @author Cliff Biffle
040 * @since 10.0
041 */
042@Retention(RetentionPolicy.RUNTIME)
043@Target(ElementType.METHOD)
044@Beta
045public @interface Subscribe {
046}