/*
* Copyright 2002-2018 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
*
* http://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.context.event;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.core.Ordered;
import org.springframework.core.ResolvableType;
import org.springframework.lang.Nullable;
Extended variant of the standard ApplicationListener
interface, exposing further metadata such as the supported event and source type. As of Spring Framework 4.2, this interface supersedes the Class-based SmartApplicationListener
with full handling of generic event types.
Author: Stephane Nicoll See Also: Since: 4.2
/**
* Extended variant of the standard {@link ApplicationListener} interface,
* exposing further metadata such as the supported event and source type.
*
* <p>As of Spring Framework 4.2, this interface supersedes the Class-based
* {@link SmartApplicationListener} with full handling of generic event types.
*
* @author Stephane Nicoll
* @since 4.2
* @see SmartApplicationListener
* @see GenericApplicationListenerAdapter
*/
public interface GenericApplicationListener extends ApplicationListener<ApplicationEvent>, Ordered {
Determine whether this listener actually supports the given event type.
Params: - eventType – the event type (never
null
)
/**
* Determine whether this listener actually supports the given event type.
* @param eventType the event type (never {@code null})
*/
boolean supportsEventType(ResolvableType eventType);
Determine whether this listener actually supports the given source type.
The default implementation always returns true
.
Params: - sourceType – the source type, or
null
if no source
/**
* Determine whether this listener actually supports the given source type.
* <p>The default implementation always returns {@code true}.
* @param sourceType the source type, or {@code null} if no source
*/
default boolean supportsSourceType(@Nullable Class<?> sourceType) {
return true;
}
Determine this listener's order in a set of listeners for the same event.
The default implementation returns Ordered.LOWEST_PRECEDENCE
.
/**
* Determine this listener's order in a set of listeners for the same event.
* <p>The default implementation returns {@link #LOWEST_PRECEDENCE}.
*/
@Override
default int getOrder() {
return LOWEST_PRECEDENCE;
}
}