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.internal.InternalConstants;
016import org.apache.tapestry5.internal.structure.Page;
017import org.apache.tapestry5.ioc.util.UnknownValueException;
018import org.apache.tapestry5.services.*;
019
020import java.io.IOException;
021
022/**
023 * A filter, used only in production mode, that does a "pre-flight check" that the indicated component
024 * actually exists. If it does not, then the handling of the component event is aborted and other
025 * hooks will ensure that request ultimately becomes a 404.
026 *
027 * @since 5.4
028 */
029public class ProductionModeUnknownComponentFilter implements ComponentRequestFilter
030{
031    private final Request request;
032
033    private final RequestPageCache cache;
034
035    public ProductionModeUnknownComponentFilter(Request request, RequestPageCache cache)
036    {
037        this.request = request;
038        this.cache = cache;
039    }
040
041    @Override
042    public void handleComponentEvent(ComponentEventRequestParameters parameters, ComponentRequestHandler handler) throws IOException
043    {
044        Page containerPage = cache.get(parameters.getContainingPageName());
045
046        try
047        {
048            containerPage.getComponentElementByNestedId(parameters.getNestedComponentId());
049
050            handler.handleComponentEvent(parameters);
051
052        } catch (UnknownValueException ex)
053        {
054            request.setAttribute(InternalConstants.REFERENCED_COMPONENT_NOT_FOUND, true);
055        }
056    }
057
058    @Override
059    public void handlePageRender(PageRenderRequestParameters parameters, ComponentRequestHandler handler) throws IOException
060    {
061        // Pass these through to the default handler.
062        handler.handlePageRender(parameters);
063    }
064}