spring ServletListenerRegistrationBean 源码

springboot ServletListenerRegistrationBean 代码

文件路径：/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/servlet/ServletListenerRegistrationBean.java

/*
 * Copyright 2012-2021 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.web.servlet;

import java.util.Collections;
import java.util.EventListener;
import java.util.HashSet;
import java.util.Set;

import jakarta.servlet.ServletContext;
import jakarta.servlet.ServletContextAttributeListener;
import jakarta.servlet.ServletContextListener;
import jakarta.servlet.ServletRequestAttributeListener;
import jakarta.servlet.ServletRequestListener;
import jakarta.servlet.http.HttpSessionAttributeListener;
import jakarta.servlet.http.HttpSessionIdListener;
import jakarta.servlet.http.HttpSessionListener;

import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;

/**
 * A {@link ServletContextInitializer} to register {@link EventListener}s in a Servlet
 * 3.0+ container. Similar to the {@link ServletContext#addListener(EventListener)
 * registration} features provided by {@link ServletContext} but with a Spring Bean
 * friendly design.
 *
 * This bean can be used to register the following types of listener:
 * <ul>
 * <li>{@link ServletContextAttributeListener}</li>
 * <li>{@link ServletRequestListener}</li>
 * <li>{@link ServletRequestAttributeListener}</li>
 * <li>{@link HttpSessionAttributeListener}</li>
 * <li>{@link HttpSessionIdListener}</li>
 * <li>{@link HttpSessionListener}</li>
 * <li>{@link ServletContextListener}</li>
 * </ul>
 *
 * @param <T> the type of listener
 * @author Dave Syer
 * @author Phillip Webb
 * @since 1.4.0
 */
public class ServletListenerRegistrationBean<T extends EventListener> extends RegistrationBean {

	private static final Set<Class<?>> SUPPORTED_TYPES;

	static {
		Set<Class<?>> types = new HashSet<>();
		types.add(ServletContextAttributeListener.class);
		types.add(ServletRequestListener.class);
		types.add(ServletRequestAttributeListener.class);
		types.add(HttpSessionAttributeListener.class);
		types.add(HttpSessionIdListener.class);
		types.add(HttpSessionListener.class);
		types.add(ServletContextListener.class);
		SUPPORTED_TYPES = Collections.unmodifiableSet(types);
	}

	private T listener;

	/**
	 * Create a new {@link ServletListenerRegistrationBean} instance.
	 */
	public ServletListenerRegistrationBean() {
	}

	/**
	 * Create a new {@link ServletListenerRegistrationBean} instance.
	 * @param listener the listener to register
	 */
	public ServletListenerRegistrationBean(T listener) {
		Assert.notNull(listener, "Listener must not be null");
		Assert.isTrue(isSupportedType(listener), "Listener is not of a supported type");
		this.listener = listener;
	}

	/**
	 * Set the listener that will be registered.
	 * @param listener the listener to register
	 */
	public void setListener(T listener) {
		Assert.notNull(listener, "Listener must not be null");
		Assert.isTrue(isSupportedType(listener), "Listener is not of a supported type");
		this.listener = listener;
	}

	/**
	 * Return the listener to be registered.
	 * @return the listener to be registered
	 */
	public T getListener() {
		return this.listener;
	}

	@Override
	protected String getDescription() {
		Assert.notNull(this.listener, "Listener must not be null");
		return "listener " + this.listener;
	}

	@Override
	protected void register(String description, ServletContext servletContext) {
		try {
			servletContext.addListener(this.listener);
		}
		catch (RuntimeException ex) {
			throw new IllegalStateException("Failed to add listener '" + this.listener + "' to servlet context", ex);
		}
	}

	/**
	 * Returns {@code true} if the specified listener is one of the supported types.
	 * @param listener the listener to test
	 * @return if the listener is of a supported type
	 */
	public static boolean isSupportedType(EventListener listener) {
		for (Class<?> type : SUPPORTED_TYPES) {
			if (ClassUtils.isAssignableValue(type, listener)) {
				return true;
			}
		}
		return false;
	}

	/**
	 * Return the supported types for this registration.
	 * @return the supported types
	 */
	public static Set<Class<?>> getSupportedTypes() {
		return SUPPORTED_TYPES;
	}

}

相关信息

spring 源码目录

相关文章

spring AbstractFilterRegistrationBean 源码

spring DelegatingFilterProxyRegistrationBean 源码

spring DispatcherType 源码

spring DynamicRegistrationBean 源码

spring FilterRegistrationBean 源码

spring MultipartConfigFactory 源码

spring RegistrationBean 源码

spring ServletComponentHandler 源码

spring ServletComponentRegisteringPostProcessor 源码

spring ServletComponentScan 源码