javax.servlet.http.HttpSessionAttributeListener Maven / Gradle / Ivy

/*
 * Copyright (c) 1997-2018 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 javax.servlet.http;

import java.util.EventListener;

/**
 * Interface for receiving notification events about HttpSession attribute changes.
 *
 * 
 * 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 javax.servlet.annotation.WebListener}, or registered via one
 * of the addListener methods defined on {@link javax.servlet.ServletContext}.
 *
 * 
 * The order in which implementations of this interface are invoked is unspecified.
 *
 * @since Servlet 2.3
 */
public interface HttpSessionAttributeListener extends EventListener {

    /**
     * Receives notification that an attribute has been added to a session.
     *
     * @param event the HttpSessionBindingEvent containing the session and the name and value of the attribute that was
     *              added
     */
    default public void attributeAdded(HttpSessionBindingEvent event) {
    }

    /**
     * Receives notification that an attribute has been removed from a session.
     *
     * @param event the HttpSessionBindingEvent containing the session and the name and value of the attribute that was
     *              removed
     */
    default public void attributeRemoved(HttpSessionBindingEvent event) {
    }

    /**
     * Receives notification that an attribute has been replaced in a session.
     *
     * @param event the HttpSessionBindingEvent containing the session and the name and (old) value of the attribute
     *              that was replaced
     */
    default public void attributeReplaced(HttpSessionBindingEvent event) {
    }

}