/*
 * 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.http;

import java.util.EventListener;

/**
 * Causes an object to be notified when it is bound to or unbound from a session. The object is notified by an
 * {@link HttpSessionBindingEvent} object. This may be as a result of a servlet programmer explicitly unbinding an
 * attribute from a session, due to a session being invalidated, or due to a session timing out.
 *
 *
 * @author Various
 *
 * @see HttpSession
 * @see HttpSessionBindingEvent
 *
 */
public interface HttpSessionBindingListener extends EventListener {

    /**
     *
     * Notifies the object that it is being bound to a session and identifies the session.
     *
     * @implSpec The default implementation takes no action.
     *
     * @param event the event that identifies the session
     *
     * @see #valueUnbound
     *
     */
    default void valueBound(HttpSessionBindingEvent event) {
    }

    /**
     *
     * Notifies the object that it is being unbound from a session and identifies the session.
     *
     * @implSpec The default implementation takes no action.
     *
     * @param event the event that identifies the session
     *
     * @see #valueBound
     *
     */
    default void valueUnbound(HttpSessionBindingEvent event) {
    }
}
