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    
015    package org.apache.tapestry.web;
016    
017    import 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     */
025    public 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    }