    001    // Copyright 2008, 2010 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.tapestry5.internal.services;
    016
    017    import java.io.IOException;
    018
    019    import org.apache.tapestry5.internal.InternalConstants;
    020    import org.apache.tapestry5.internal.structure.Page;
    021    import org.apache.tapestry5.services.Request;
    022
    023    /**
    024     * Alternative implementation, used when {@link org.apache.tapestry5.SymbolConstants#SUPPRESS_REDIRECT_FROM_ACTION_REQUESTS}
    025     * is set to true.
    026     */
    027    public class ImmediateActionRenderResponseGenerator implements ActionRenderResponseGenerator
    028    {
    029        private final Request request;
    030
    031        public ImmediateActionRenderResponseGenerator(Request request)
    032        {
    033            this.request = request;
    034        }
    035
    036        public void generateResponse(Page page) throws IOException
    037        {
    038            assert page != null;
    039            if (request.getAttribute(InternalConstants.IMMEDIATE_RESPONSE_PAGE_ATTRIBUTE) != null) return;
    040
    041            // We are somewhere in the middle of processing an action request, possibly something
    042            // complicated like a form submission.  Tapestry components are not re-entrant, so we
    043            // can't render the request right now, instead we record that we need to render
    044            // a response as an attribute, and let a filter on the ComponentEventRequestHandler service
    045            // do the work.
    046
    047            request.setAttribute(InternalConstants.IMMEDIATE_RESPONSE_PAGE_ATTRIBUTE, page);
    048        }
    049    }