001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
004//
005// http://www.apache.org/licenses/LICENSE-2.0
006//
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
012
013package org.apache.tapestry5.internal.services;
014
015import org.apache.tapestry5.TrackableComponentEventCallback;
016import org.apache.tapestry5.beanmodel.services.*;
017import org.apache.tapestry5.commons.internal.util.TapestryException;
018import org.apache.tapestry5.http.services.Response;
019import org.apache.tapestry5.internal.EmptyEventContext;
020import org.apache.tapestry5.internal.structure.ComponentPageElement;
021import org.apache.tapestry5.internal.structure.Page;
022import org.apache.tapestry5.ioc.annotations.Primary;
023import org.apache.tapestry5.services.ComponentEventRequestHandler;
024import org.apache.tapestry5.services.ComponentEventRequestParameters;
025import org.apache.tapestry5.services.ComponentEventResultProcessor;
026import org.apache.tapestry5.services.Environment;
027import org.apache.tapestry5.services.Traditional;
028
029import java.io.IOException;
030
031@SuppressWarnings("unchecked")
032public class ComponentEventRequestHandlerImpl implements ComponentEventRequestHandler
033{
034    private final ComponentEventResultProcessor resultProcessor;
035
036    private final RequestPageCache cache;
037
038    private final Response response;
039
040    private final PageActivator pageActivator;
041
042    private final Environment environment;
043
044    public ComponentEventRequestHandlerImpl(@Traditional
045                                            @Primary
046                                            ComponentEventResultProcessor resultProcessor,
047
048                                            RequestPageCache cache, Response response,
049
050                                            PageActivator pageActivator,
051
052                                            Environment environment)
053    {
054        this.resultProcessor = resultProcessor;
055        this.cache = cache;
056        this.response = response;
057        this.pageActivator = pageActivator;
058        this.environment = environment;
059    }
060
061    public void handle(ComponentEventRequestParameters parameters) throws IOException
062    {
063        Page activePage = cache.get(parameters.getActivePageName());
064
065        if (pageActivator.activatePage(activePage.getRootElement().getComponentResources(), parameters
066                .getPageActivationContext(), resultProcessor))
067        {
068            return;
069        }
070
071        Page containerPage = cache.get(parameters.getContainingPageName());
072
073        // When the event targets a component from a different page than the active page, the
074        // containing page also has code executing for this request, and must also trigger its
075        // activation event.
076        // An empty context is used because the activation context in the request belongs to
077        // the active page.
078        if (containerPage != activePage
079                && pageActivator.activatePage(containerPage.getRootElement().getComponentResources(),
080                        new EmptyEventContext(), resultProcessor))
081        {
082            return;
083        }
084
085        TrackableComponentEventCallback callback = new ComponentResultProcessorWrapper(resultProcessor);
086
087        environment.push(ComponentEventResultProcessor.class, resultProcessor);
088        environment.push(TrackableComponentEventCallback.class, callback);
089
090        ComponentPageElement element = containerPage.getComponentElementByNestedId(parameters.getNestedComponentId());
091
092        boolean handled = element.triggerContextEvent(parameters.getEventType(), parameters.getEventContext(), callback);
093
094        if (!handled)
095        {
096            throw new TapestryException(String.format("Request event '%s' (on component %s) was not handled; you must provide a matching event handler method in the component or in one of its containers.", parameters.getEventType(), element.getCompleteId()), element,
097                    null);
098        }
099
100        environment.pop(TrackableComponentEventCallback.class);
101        environment.pop(ComponentEventResultProcessor.class);
102
103        if (callback.isAborted())
104        {
105            callback.rethrow();
106            return;
107        }
108
109        // If we get this far without generating a response, the default behavior is to
110        // generate a redirect back to the active page; we can let the ComponentEventResultProcessor handle that.
111
112        if (!response.isCommitted())
113        {
114            resultProcessor.processResultValue(activePage.getName());
115        }
116    }
117}