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    
015    package org.apache.tapestry.engine;
016    
017    import java.io.IOException;
018    import java.util.HashMap;
019    import java.util.Map;
020    
021    import org.apache.hivemind.ApplicationRuntimeException;
022    import org.apache.hivemind.util.Defense;
023    import org.apache.tapestry.IAction;
024    import org.apache.tapestry.IComponent;
025    import org.apache.tapestry.IPage;
026    import org.apache.tapestry.IRequestCycle;
027    import org.apache.tapestry.StaleSessionException;
028    import org.apache.tapestry.Tapestry;
029    import org.apache.tapestry.services.LinkFactory;
030    import org.apache.tapestry.services.ResponseRenderer;
031    import org.apache.tapestry.services.ServiceConstants;
032    import org.apache.tapestry.web.WebRequest;
033    import org.apache.tapestry.web.WebSession;
034    
035    /**
036     * A context-sensitive service related to {@link org.apache.tapestry.form.Form}and
037     * {@link org.apache.tapestry.link.ActionLink}. Encodes the page, component and an action id in the
038     * service context.
039     * 
040     * @author Howard Lewis Ship
041     * @since 1.0.9
042     */
043    
044    public class ActionService implements IEngineService
045    {
046        /** @since 4.0 */
047        private ResponseRenderer _responseRenderer;
048    
049        /** @since 4.0 */
050        private LinkFactory _linkFactory;
051    
052        /** @since 4.0 */
053        private static final String ACTION = "action";
054    
055        /** @since 4.0 */
056        private WebRequest _request;
057    
058        public ILink getLink(IRequestCycle cycle, boolean post, Object parameter)
059        {
060            Defense.isAssignable(parameter, ActionServiceParameter.class, "parameter");
061    
062            ActionServiceParameter asp = (ActionServiceParameter) parameter;
063    
064            IComponent component = asp.getComponent();
065            IPage activePage = cycle.getPage();
066            IPage componentPage = component.getPage();
067    
068            Map parameters = new HashMap();
069    
070            boolean stateful = _request.getSession(false) != null;
071    
072            parameters.put(ServiceConstants.SERVICE, getName());
073            parameters.put(ServiceConstants.COMPONENT, component.getIdPath());
074            parameters.put(ServiceConstants.PAGE, activePage.getPageName());
075            parameters.put(ServiceConstants.CONTAINER, activePage == componentPage ? null
076                    : componentPage.getPageName());
077            parameters.put(ACTION, asp.getActionId());
078            parameters.put(ServiceConstants.SESSION, stateful ? "T" : null);
079    
080            return _linkFactory.constructLink(cycle, post, parameters, true);
081        }
082    
083        public void service(IRequestCycle cycle) throws IOException
084        {
085            String componentId = cycle.getParameter(ServiceConstants.COMPONENT);
086            String componentPageName = cycle.getParameter(ServiceConstants.CONTAINER);
087            String activePageName = cycle.getParameter(ServiceConstants.PAGE);
088            String actionId = cycle.getParameter(ACTION);
089            boolean activeSession = cycle.getParameter(ServiceConstants.SESSION) != null;
090    
091            IPage page = cycle.getPage(activePageName);
092    
093            // Setup the page for the rewind, then do the rewind.
094    
095            cycle.activate(page);
096    
097            IPage componentPage = componentPageName == null ? page : cycle.getPage(componentPageName);
098    
099            IComponent component = componentPage.getNestedComponent(componentId);
100    
101            IAction action = null;
102    
103            try
104            {
105                action = (IAction) component;
106            }
107            catch (ClassCastException ex)
108            {
109                throw new ApplicationRuntimeException(EngineMessages.wrongComponentType(
110                        component,
111                        IAction.class), component, null, ex);
112            }
113    
114            // Only perform the stateful check if the application was stateful
115            // when the URL was rendered.
116    
117            if (activeSession && action.getRequiresSession())
118            {
119                WebSession session = _request.getSession(false);
120    
121                if (session == null || session.isNew())
122                    throw new StaleSessionException(EngineMessages.requestStateSession(component),
123                            componentPage);
124    
125            }
126    
127            cycle.rewindPage(actionId, action);
128    
129            // During the rewind, a component may change the page. This will take
130            // effect during the second render, which renders the HTML response.
131    
132            // Render that response.
133    
134            _responseRenderer.renderResponse(cycle);
135        }
136    
137        public String getName()
138        {
139            return Tapestry.ACTION_SERVICE;
140        }
141    
142        /** @since 4.0 */
143        public void setResponseRenderer(ResponseRenderer responseRenderer)
144        {
145            _responseRenderer = responseRenderer;
146        }
147    
148        /** @since 4.0 */
149        public void setLinkFactory(LinkFactory linkFactory)
150        {
151            _linkFactory = linkFactory;
152        }
153    
154        /** @since 4.0 */
155        public void setRequest(WebRequest request)
156        {
157            _request = request;
158        }
159    }