001    // Copyright 2004, 2005 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.tapestry.multipart;
016    
017    import javax.servlet.http.HttpServletRequest;
018    
019    import org.apache.tapestry.request.IUploadFile;
020    
021    /**
022     * Defines how a multipart HTTP request can be broken into individual elements (including file
023     * uploads).
024     * <p>
025     * Multipart decoder implementations must be threadsafe.
026     * 
027     * @author Howard Lewis Ship
028     * @since 2.3
029     */
030    
031    public interface IMultipartDecoder
032    {
033        /**
034         * Decodes the incoming request, identifying all the parts (values and uploaded files) contained
035         * within.
036         */
037    
038        public void decode(HttpServletRequest request);
039    
040        /**
041         * Invoked to release any resources needed by tghe decoder. In some cases, large incoming parts
042         * are written to temporary files; this method ensures those temporary files are deleted.
043         */
044    
045        public void cleanup(HttpServletRequest request);
046    
047        /**
048         * Returns the single value (or first value) for the parameter with the specified name. Returns
049         * null if no such parameter was in the request.
050         */
051    
052        public String getString(HttpServletRequest request, String name);
053    
054        /**
055         * Returns an array of values (possibly a single element array). Returns null if no such
056         * parameter was in the request.
057         */
058    
059        public String[] getStrings(HttpServletRequest request, String name);
060    
061        /**
062         * Returns the uploaded file with the specified parameter name, or null if no such parameter was
063         * in the request.
064         */
065    
066        public IUploadFile getUploadFile(HttpServletRequest request, String name);
067    
068        /**
069         * Returns the names of all parameters whose type is string (not file upload).
070         * 
071         * @since 4.0
072         */
073        public String[] getStringParameterNames(HttpServletRequest request);
074    }