001// Copyright 2005 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.tapestry.web;
016
017import org.apache.tapestry.describe.Describable;
018
019/**
020 * Primarily concerned with maintaining server-side state as attributes.
021 * 
022 * @author Howard M. Lewis Ship
023 * @since 4.0
024 */
025public interface WebSession extends AttributeHolder, Describable
026{
027    /**
028     * Returns a unique string identifier used to identify the session. This value is provided by
029     * the container, and is typically incorporated into URLs, or stored as a HTTP cookie.
030     * 
031     * @see org.apache.tapestry.web.WebResponse#encodeURL(String).
032     */
033    public String getId();
034
035    /**
036     * Returns true if the client does not yet know about the session or if the client chooses not
037     * to join the session.
038     */
039    public boolean isNew();
040
041    /**
042     * Invalidates this session then unbinds any objects bound to it.
043     * 
044     * @throws IllegalStateException
045     *             if the session is already invalidated.
046     */
047
048    public void invalidate();
049}