org.springframework.integration.annotation.Aggregator Maven / Gradle / Ivy
/*
* Copyright 2002-2019 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.integration.annotation;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Indicates that a method is capable of aggregating messages.
*
* A method annotated with @Aggregator may accept a collection
* of Messages or Message payloads and should return a single
* Message or a single Object to be used as a Message payload.
*
* @author Marius Bogoevici
* @author Oleg Zhurakousky
* @author Artem Bilan
*/
@Target({ ElementType.METHOD, ElementType.ANNOTATION_TYPE })
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Aggregator {
/**
* @return The channel name for receiving messages to be aggregated
*/
String inputChannel() default "";
/**
* @return The channel name for sending aggregated result messages
*/
String outputChannel() default "";
/**
* @return The channel name for sending discarded messages (due to a timeout)
*/
String discardChannel() default "";
/**
* Specify the maximum amount of time in milliseconds to wait when sending a reply
* {@link org.springframework.messaging.Message} to the {@link #outputChannel()}.
* Defaults to {@code -1} - blocking indefinitely.
* It is applied only if the output channel has some 'sending' limitations, e.g.
* {@link org.springframework.integration.channel.QueueChannel} with
* a fixed 'capacity' and is currently full.
* In this case a {@link org.springframework.messaging.MessageDeliveryException} is thrown.
* The 'sendTimeout' is ignored in case of
* {@link org.springframework.integration.channel.AbstractSubscribableChannel} implementations.
* Can be specified as 'property placeholder', e.g. {@code ${spring.integration.sendTimeout}}.
* @return The timeout for sending results to the reply target (in milliseconds)
*/
String sendTimeout() default "";
/**
* Specify whether messages that expired should be aggregated and sent to the {@link #outputChannel()}
* or {@code replyChannel} from message headers. Messages are expired when their containing
* {@link org.springframework.integration.store.MessageGroup} expires. One of the ways of expiring MessageGroups
* is by configuring a {@link org.springframework.integration.store.MessageGroupStoreReaper}.
* However MessageGroups can alternatively be expired by simply calling
* {@code MessageGroupStore.expireMessageGroup(groupId)}. That could be accomplished via a ControlBus operation
* or by simply invoking that method if you have a reference to the
* {@link org.springframework.integration.store.MessageGroupStore} instance.
* Defaults to {@code false}.
* * Can be specified as 'property placeholder', e.g. {@code ${spring.integration.sendPartialResultsOnExpiry}}.
* @return Indicates whether to send an incomplete aggregate on expiry of the message group
*/
String sendPartialResultsOnExpiry() default "";
/**
* The {@link org.springframework.context.SmartLifecycle} {@code autoStartup} option.
* Can be specified as 'property placeholder', e.g. {@code ${foo.autoStartup}}.
* Defaults to {@code true}.
* @return the auto startup {@code boolean} flag.
*/
String autoStartup() default "";
/**
* Specify a {@link org.springframework.context.SmartLifecycle} {@code phase} option.
* Defaults {@code Integer.MAX_VALUE / 2} for {@link org.springframework.integration.endpoint.PollingConsumer}
* and {@code Integer.MIN_VALUE} for {@link org.springframework.integration.endpoint.EventDrivenConsumer}.
* Can be specified as 'property placeholder', e.g. {@code ${foo.phase}}.
* @return the {@code SmartLifecycle} phase.
*/
String phase() default "";
/**
* @return the {@link Poller} options for a polled endpoint
* ({@link org.springframework.integration.scheduling.PollerMetadata}).
* This attribute is an {@code array} just to allow an empty default (no poller).
* Only one {@link Poller} element is allowed.
*/
Poller[] poller() default { };
}