/*
 * Copyright (c) 1997, 2023 Oracle and/or its affiliates and others.
 * All rights reserved.
 * Copyright 2004 The Apache Software Foundation
 *
 * 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 jakarta.servlet;

import java.util.EventListener;

/**
 * Interface for receiving notification events about requests coming into and going out of scope of a web application.
 *
 * <p>
 * A ServletRequest is defined as coming into scope of a web application when it is about to enter the first servlet or
 * filter of the web application, and as going out of scope as it exits the last servlet or the first filter in the
 * chain.
 *
 * <p>
 * In order to receive these notification events, the implementation class must be either declared in the deployment
 * descriptor of the web application, annotated with {@link jakarta.servlet.annotation.WebListener}, or registered via
 * one of the addListener methods defined on {@link ServletContext}.
 *
 * <p>
 * Implementations of this interface are invoked at their {@link #requestInitialized} method in the order in which they
 * have been declared, and at their {@link #requestDestroyed} method in reverse order.
 *
 * @since Servlet 2.4
 */
public interface ServletRequestListener extends EventListener {

    /**
     * Receives notification that a ServletRequest is about to go out of scope of the web application.
     *
     * @param sre the ServletRequestEvent containing the ServletRequest and the ServletContext representing the web
     * application
     *
     * @implSpec The default implementation takes no action.
     */
    default void requestDestroyed(ServletRequestEvent sre) {
    }

    /**
     * Receives notification that a ServletRequest is about to come into scope of the web application.
     *
     * @param sre the ServletRequestEvent containing the ServletRequest and the ServletContext representing the web
     * application
     *
     * @implSpec The default implementation takes no action.
     */
    default void requestInitialized(ServletRequestEvent sre) {
    }
}
