org.springframework.boot.builder.ParentContextApplicationContextInitializer Maven / Gradle / Ivy
/*
* Copyright 2012-2018 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
*
* 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.boot.builder;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextInitializer;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.core.Ordered;
/**
* {@link ApplicationContextInitializer} for setting the parent context. Also publishes
* {@link ParentContextAvailableEvent} when the context is refreshed to signal to other
* listeners that the context is available and has a parent.
*
* @author Dave Syer
*/
public class ParentContextApplicationContextInitializer implements
ApplicationContextInitializer, Ordered {
private int order = Ordered.HIGHEST_PRECEDENCE;
private final ApplicationContext parent;
public ParentContextApplicationContextInitializer(ApplicationContext parent) {
this.parent = parent;
}
public void setOrder(int order) {
this.order = order;
}
@Override
public int getOrder() {
return this.order;
}
@Override
public void initialize(ConfigurableApplicationContext applicationContext) {
if (applicationContext != this.parent) {
applicationContext.setParent(this.parent);
applicationContext.addApplicationListener(EventPublisher.INSTANCE);
}
}
private static class EventPublisher
implements ApplicationListener, Ordered {
private static final EventPublisher INSTANCE = new EventPublisher();
@Override
public int getOrder() {
return Ordered.HIGHEST_PRECEDENCE;
}
@Override
public void onApplicationEvent(ContextRefreshedEvent event) {
ApplicationContext context = event.getApplicationContext();
if (context instanceof ConfigurableApplicationContext
&& context == event.getSource()) {
context.publishEvent(new ParentContextAvailableEvent(
(ConfigurableApplicationContext) context));
}
}
}
/**
* {@link ApplicationEvent} fired when a parent context is available.
*/
@SuppressWarnings("serial")
public static class ParentContextAvailableEvent extends ApplicationEvent {
public ParentContextAvailableEvent(
ConfigurableApplicationContext applicationContext) {
super(applicationContext);
}
public ConfigurableApplicationContext getApplicationContext() {
return (ConfigurableApplicationContext) getSource();
}
}
}