001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.fileupload; 018 019import java.io.File; 020import java.io.IOException; 021import java.io.InputStream; 022import java.io.OutputStream; 023import java.io.UnsupportedEncodingException; 024 025/** 026 * <p> This class represents a file or form item that was received within a 027 * <code>multipart/form-data</code> POST request. 028 * 029 * <p> After retrieving an instance of this class from a {@link 030 * org.apache.commons.fileupload.FileUpload FileUpload} instance (see 031 * {@link org.apache.commons.fileupload.servlet.ServletFileUpload 032 * #parseRequest(javax.servlet.http.HttpServletRequest)}), you may 033 * either request all contents of the file at once using {@link #get()} or 034 * request an {@link java.io.InputStream InputStream} with 035 * {@link #getInputStream()} and process the file without attempting to load 036 * it into memory, which may come handy with large files. 037 * 038 * <p> While this interface does not extend 039 * <code>javax.activation.DataSource</code> per se (to avoid a seldom used 040 * dependency), several of the defined methods are specifically defined with 041 * the same signatures as methods in that interface. This allows an 042 * implementation of this interface to also implement 043 * <code>javax.activation.DataSource</code> with minimal additional work. 044 * 045 * @since 1.3 additionally implements FileItemHeadersSupport 046 */ 047public interface FileItem extends FileItemHeadersSupport { 048 049 // ------------------------------- Methods from javax.activation.DataSource 050 051 /** 052 * Returns an {@link java.io.InputStream InputStream} that can be 053 * used to retrieve the contents of the file. 054 * 055 * @return An {@link java.io.InputStream InputStream} that can be 056 * used to retrieve the contents of the file. 057 * 058 * @throws IOException if an error occurs. 059 */ 060 InputStream getInputStream() throws IOException; 061 062 /** 063 * Returns the content type passed by the browser or <code>null</code> if 064 * not defined. 065 * 066 * @return The content type passed by the browser or <code>null</code> if 067 * not defined. 068 */ 069 String getContentType(); 070 071 /** 072 * Returns the original filename in the client's filesystem, as provided by 073 * the browser (or other client software). In most cases, this will be the 074 * base file name, without path information. However, some clients, such as 075 * the Opera browser, do include path information. 076 * 077 * @return The original filename in the client's filesystem. 078 * @throws InvalidFileNameException The file name contains a NUL character, 079 * which might be an indicator of a security attack. If you intend to 080 * use the file name anyways, catch the exception and use 081 * InvalidFileNameException#getName(). 082 */ 083 String getName(); 084 085 // ------------------------------------------------------- FileItem methods 086 087 /** 088 * Provides a hint as to whether or not the file contents will be read 089 * from memory. 090 * 091 * @return <code>true</code> if the file contents will be read from memory; 092 * <code>false</code> otherwise. 093 */ 094 boolean isInMemory(); 095 096 /** 097 * Returns the size of the file item. 098 * 099 * @return The size of the file item, in bytes. 100 */ 101 long getSize(); 102 103 /** 104 * Returns the contents of the file item as an array of bytes. 105 * 106 * @return The contents of the file item as an array of bytes. 107 */ 108 byte[] get(); 109 110 /** 111 * Returns the contents of the file item as a String, using the specified 112 * encoding. This method uses {@link #get()} to retrieve the 113 * contents of the item. 114 * 115 * @param encoding The character encoding to use. 116 * 117 * @return The contents of the item, as a string. 118 * 119 * @throws UnsupportedEncodingException if the requested character 120 * encoding is not available. 121 */ 122 String getString(String encoding) throws UnsupportedEncodingException; 123 124 /** 125 * Returns the contents of the file item as a String, using the default 126 * character encoding. This method uses {@link #get()} to retrieve the 127 * contents of the item. 128 * 129 * @return The contents of the item, as a string. 130 */ 131 String getString(); 132 133 /** 134 * A convenience method to write an uploaded item to disk. The client code 135 * is not concerned with whether or not the item is stored in memory, or on 136 * disk in a temporary location. They just want to write the uploaded item 137 * to a file. 138 * <p> 139 * This method is not guaranteed to succeed if called more than once for 140 * the same item. This allows a particular implementation to use, for 141 * example, file renaming, where possible, rather than copying all of the 142 * underlying data, thus gaining a significant performance benefit. 143 * 144 * @param file The <code>File</code> into which the uploaded item should 145 * be stored. 146 * 147 * @throws Exception if an error occurs. 148 */ 149 void write(File file) throws Exception; 150 151 /** 152 * Deletes the underlying storage for a file item, including deleting any 153 * associated temporary disk file. Although this storage will be deleted 154 * automatically when the <code>FileItem</code> instance is garbage 155 * collected, this method can be used to ensure that this is done at an 156 * earlier time, thus preserving system resources. 157 */ 158 void delete(); 159 160 /** 161 * Returns the name of the field in the multipart form corresponding to 162 * this file item. 163 * 164 * @return The name of the form field. 165 */ 166 String getFieldName(); 167 168 /** 169 * Sets the field name used to reference this file item. 170 * 171 * @param name The name of the form field. 172 */ 173 void setFieldName(String name); 174 175 /** 176 * Determines whether or not a <code>FileItem</code> instance represents 177 * a simple form field. 178 * 179 * @return <code>true</code> if the instance represents a simple form 180 * field; <code>false</code> if it represents an uploaded file. 181 */ 182 boolean isFormField(); 183 184 /** 185 * Specifies whether or not a <code>FileItem</code> instance represents 186 * a simple form field. 187 * 188 * @param state <code>true</code> if the instance represents a simple form 189 * field; <code>false</code> if it represents an uploaded file. 190 */ 191 void setFormField(boolean state); 192 193 /** 194 * Returns an {@link java.io.OutputStream OutputStream} that can 195 * be used for storing the contents of the file. 196 * 197 * @return An {@link java.io.OutputStream OutputStream} that can be used 198 * for storing the contensts of the file. 199 * 200 * @throws IOException if an error occurs. 201 */ 202 OutputStream getOutputStream() throws IOException; 203 204}