    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
    017    package com.google.common.eventbus;
    018
    019    import com.google.common.annotations.Beta;
    020
    021    import java.lang.annotation.ElementType;
    022    import java.lang.annotation.Retention;
    023    import java.lang.annotation.RetentionPolicy;
    024    import 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
    045    public @interface Subscribe {
    046    }