001// Copyright 2004, 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;
016
017/**
018 *  Interface that defines classes that may be messaged by the direct
019 *  service.
020 *
021 *  @author Howard Lewis Ship
022 **/
023
024public interface IDirect extends IComponent
025{
026    /**
027     *  Invoked by the direct service to have the component peform
028     *  the appropriate action.  The {@link org.apache.tapestry.link.DirectLink} component will
029     *  notify its listener.
030     *
031     **/
032
033    public void trigger(IRequestCycle cycle);
034
035    /**
036     *  Invoked by the direct service to query the component as to
037     *  whether it is stateful.  If stateful and no 
038     *  {@link javax.servlet.http.HttpSession} is active, then a
039     *  {@link org.apache.tapestry.StaleSessionException} is
040     *  thrown by the service.
041     * 
042     *  @since 2.3
043     * 
044     **/
045
046    public boolean isStateful();
047
048}