    001// Copyright 2006, 2008, 2020 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007// http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5.http.services;
    016
    017import java.util.List;
    018
    019import javax.servlet.http.HttpSession;
    020
    021import org.apache.tapestry5.http.OptimizedSessionPersistedObject;
    022import org.apache.tapestry5.http.annotations.ImmutableSessionPersistedObject;
    023import org.apache.tapestry5.http.internal.services.OptimizedSessionPersistedObjectAnalyzer;
    024
    025/**
    026 * Generic version of {@link HttpSession}, used to bridge the gaps between the Servlet API and the Portlet API.
    027 */
    028public interface Session
    029{
    030    /**
    031     * Returns a list of the names of all attributes stored in the session. The names are returned sorted
    032     * alphabetically.
    033     */
    034    List<String> getAttributeNames();
    035
    036    /**
    037     * Returns a list of the names of all attributes stored in the session whose name has the provided prefix. The names
    038     * are returned in alphabetical order.
    039     */
    040    List<String> getAttributeNames(String prefix);
    041
    042    /**
    043     * Returns the value previously stored in the session.
    044     */
    045    Object getAttribute(String name);
    046
    047    /**
    048     * Sets the value of an attribute. If the value is null, then the attribute is deleted.
    049     */
    050    void setAttribute(String name, Object value);
    051
    052    /**
    053     * Returns the maximum time interval, in seconds, that the servlet container will keep this session open between
    054     * client accesses. After this interval, the servlet container will invalidate the session. The maximum time
    055     * interval can be set with the setMaxInactiveInterval method. A negative time indicates the session should never
    056     * timeout.
    057     */
    058    int getMaxInactiveInterval();
    059
    060    /**
    061     * Specifies the time, in seconds, between client requests before the servlet container will invalidate this
    062     * session. A negative time indicates the session should never timeout.
    063     */
    064    void setMaxInactiveInterval(int seconds);
    065
    066    /**
    067     * Invalidates this session then unbinds any objects bound to it.
    068     *
    069     * @throws IllegalStateException
    070     *             if this method is called on an already invalidated session
    071     */
    072    void invalidate();
    073
    074    /**
    075     * Checks to see if the session has been invalidated. Note: since 5.3 this will also catch calls to
    076     * {@link javax.servlet.http.HttpSession#invalidate()}.
    077     *
    078     * @since 5.1.0.0
    079     */
    080    boolean isInvalidated();
    081
    082    /**
    083     * Re-stores dirty objects back into the session. This is necessary to support clustering, because (in most
    084     * application servers) session objects are only broadcast around the cluster from setAttribute(). If a mutable
    085     * session object is read and changed, those changes will be limited to a single server in the cluster, which can
    086     * cause confusing application failures in the event of a failover. Does nothing if there are no changes, or
    087     * the session has been invalidated.
    088     *
    089     * @see OptimizedSessionPersistedObject
    090     * @see OptimizedSessionPersistedObjectAnalyzer
    091     * @see ImmutableSessionPersistedObject
    092     * @since 5.1.0.0
    093     */
    094    void restoreDirtyObjects();
    095}