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