    001// Copyright 2007, 2008 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.upload.services;
    016
    017import org.apache.commons.fileupload.FileUploadException;
    018
    019import javax.servlet.http.HttpServletRequest;
    020
    021/**
    022 * Responsible for detecting and processing file upload requests, using Jakarta Commons FileUpload. Implementations of
    023 * this service typically use the threaded service lifecycle model.
    024 */
    025public interface MultipartDecoder
    026{
    027
    028    /**
    029     * @param parameterName Name of the query parameter associated with the uploaded file
    030     * @return a file upload with the given name, or null if no such file upload was in the request.
    031     */
    032    UploadedFile getFileUpload(String parameterName);
    033
    034    /**
    035     * Decodes the request, returning a new {@link javax.servlet.http.HttpServletRequest} implementation that will allow
    036     * access to the form fields submitted in the request (but omits uploaded files).
    037     *
    038     * @param request The incoming servlet request
    039     * @return decoded http request
    040     */
    041    HttpServletRequest decode(HttpServletRequest request);
    042
    043    /**
    044     * Returns the exception the occured during the file upload, or null if the processing of the multipart upload
    045     * stream was succesful.
    046     */
    047    FileUploadException getUploadException();
    048}