    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.beanmodel.services.*;
    016import org.apache.tapestry5.http.services.Dispatcher;
    017import org.apache.tapestry5.http.services.Request;
    018import org.apache.tapestry5.http.services.Response;
    019import org.apache.tapestry5.internal.InternalConstants;
    020import org.apache.tapestry5.services.ComponentEventLinkEncoder;
    021import org.apache.tapestry5.services.ComponentEventRequestParameters;
    022import org.apache.tapestry5.services.ComponentRequestHandler;
    023
    024import java.io.IOException;
    025
    026/**
    027 * Processes component action events sent as requests from the client. Component events include an event type, identify
    028 * a page and a component, and may provide additional context strings.
    029 *
    030 * @see org.apache.tapestry5.services.ComponentEventLinkEncoder
    031 */
    032public class ComponentEventDispatcher implements Dispatcher
    033{
    034    private final ComponentRequestHandler componentRequestHandler;
    035
    036    private final ComponentEventLinkEncoder linkEncoder;
    037
    038    public ComponentEventDispatcher(ComponentRequestHandler componentRequestHandler,
    039                                    ComponentEventLinkEncoder linkEncoder)
    040    {
    041        this.componentRequestHandler = componentRequestHandler;
    042        this.linkEncoder = linkEncoder;
    043    }
    044
    045    public boolean dispatch(Request request, Response response) throws IOException
    046    {
    047        ComponentEventRequestParameters parameters = linkEncoder.decodeComponentEventRequest(request);
    048
    049        if (parameters == null) return false;
    050
    051        // Inside this pipeline, may find that the component id does not exist (this check only occurs in production
    052        // mode) ...
    053
    054        componentRequestHandler.handleComponentEvent(parameters);
    055
    056        // ... in which case, this attribute is set.
    057        if (request.getAttribute(InternalConstants.REFERENCED_COMPONENT_NOT_FOUND) != null) {
    058            return false;
    059        }
    060
    061        return true;
    062    }
    063}