001/*
002 * Copyright 2002-2020 the original author or 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 *      https://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 org.springframework.transaction.event;
018
019import java.lang.annotation.Documented;
020import java.lang.annotation.ElementType;
021import java.lang.annotation.Retention;
022import java.lang.annotation.RetentionPolicy;
023import java.lang.annotation.Target;
024
025import org.springframework.context.event.EventListener;
026import org.springframework.core.annotation.AliasFor;
027
028/**
029 * An {@link EventListener} that is invoked according to a {@link TransactionPhase}.
030 *
031 * <p>If the event is not published within an active transaction, the event is discarded
032 * unless the {@link #fallbackExecution} flag is explicitly set. If a transaction is
033 * running, the event is processed according to its {@code TransactionPhase}.
034 *
035 * <p>Adding {@link org.springframework.core.annotation.Order @Order} to your annotated
036 * method allows you to prioritize that listener amongst other listeners running before
037 * or after transaction completion.
038 *
039 * <p><b>NOTE: Transactional event listeners only work with thread-bound transactions
040 * managed by {@link org.springframework.transaction.PlatformTransactionManager}.</b>
041 * A reactive transaction managed by {@link org.springframework.transaction.ReactiveTransactionManager}
042 * uses the Reactor context instead of thread-local attributes, so from the perspective of
043 * an event listener, there is no compatible active transaction that it can participate in.
044 *
045 * @author Stephane Nicoll
046 * @author Sam Brannen
047 * @since 4.2
048 */
049@Target({ElementType.METHOD, ElementType.ANNOTATION_TYPE})
050@Retention(RetentionPolicy.RUNTIME)
051@Documented
052@EventListener
053public @interface TransactionalEventListener {
054
055        /**
056         * Phase to bind the handling of an event to.
057         * <p>The default phase is {@link TransactionPhase#AFTER_COMMIT}.
058         * <p>If no transaction is in progress, the event is not processed at
059         * all unless {@link #fallbackExecution} has been enabled explicitly.
060         */
061        TransactionPhase phase() default TransactionPhase.AFTER_COMMIT;
062
063        /**
064         * Whether the event should be processed if no transaction is running.
065         */
066        boolean fallbackExecution() default false;
067
068        /**
069         * Alias for {@link #classes}.
070         */
071        @AliasFor(annotation = EventListener.class, attribute = "classes")
072        Class<?>[] value() default {};
073
074        /**
075         * The event classes that this listener handles.
076         * <p>If this attribute is specified with a single value, the annotated
077         * method may optionally accept a single parameter. However, if this
078         * attribute is specified with multiple values, the annotated method
079         * must <em>not</em> declare any parameters.
080         */
081        @AliasFor(annotation = EventListener.class, attribute = "classes")
082        Class<?>[] classes() default {};
083
084        /**
085         * Spring Expression Language (SpEL) attribute used for making the event
086         * handling conditional.
087         * <p>The default is {@code ""}, meaning the event is always handled.
088         * @see EventListener#condition
089         */
090        String condition() default "";
091
092}