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
015package org.apache.tapestry5.internal.services;
016
017import java.io.IOException;
018
019import org.apache.tapestry5.internal.InternalConstants;
020import org.apache.tapestry5.internal.structure.Page;
021import 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 */
027public 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}