1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.fileupload; 18 19 import java.io.File; 20 import java.io.IOException; 21 import java.io.InputStream; 22 import java.io.OutputStream; 23 import java.io.UnsupportedEncodingException; 24 25 /** 26 * <p> This class represents a file or form item that was received within a 27 * <code>multipart/form-data</code> POST request. 28 * 29 * <p> After retrieving an instance of this class from a {@link 30 * org.apache.commons.fileupload.FileUpload FileUpload} instance (see 31 * {@link org.apache.commons.fileupload.servlet.ServletFileUpload 32 * #parseRequest(javax.servlet.http.HttpServletRequest)}), you may 33 * either request all contents of the file at once using {@link #get()} or 34 * request an {@link java.io.InputStream InputStream} with 35 * {@link #getInputStream()} and process the file without attempting to load 36 * it into memory, which may come handy with large files. 37 * 38 * <p> While this interface does not extend 39 * <code>javax.activation.DataSource</code> per se (to avoid a seldom used 40 * dependency), several of the defined methods are specifically defined with 41 * the same signatures as methods in that interface. This allows an 42 * implementation of this interface to also implement 43 * <code>javax.activation.DataSource</code> with minimal additional work. 44 * 45 * @since 1.3 additionally implements FileItemHeadersSupport 46 */ 47 public interface FileItem extends FileItemHeadersSupport { 48 49 // ------------------------------- Methods from javax.activation.DataSource 50 51 /** 52 * Returns an {@link java.io.InputStream InputStream} that can be 53 * used to retrieve the contents of the file. 54 * 55 * @return An {@link java.io.InputStream InputStream} that can be 56 * used to retrieve the contents of the file. 57 * 58 * @throws IOException if an error occurs. 59 */ 60 InputStream getInputStream() throws IOException; 61 62 /** 63 * Returns the content type passed by the browser or <code>null</code> if 64 * not defined. 65 * 66 * @return The content type passed by the browser or <code>null</code> if 67 * not defined. 68 */ 69 String getContentType(); 70 71 /** 72 * Returns the original filename in the client's filesystem, as provided by 73 * the browser (or other client software). In most cases, this will be the 74 * base file name, without path information. However, some clients, such as 75 * the Opera browser, do include path information. 76 * 77 * @return The original filename in the client's filesystem. 78 * @throws InvalidFileNameException The file name contains a NUL character, 79 * which might be an indicator of a security attack. If you intend to 80 * use the file name anyways, catch the exception and use 81 * InvalidFileNameException#getName(). 82 */ 83 String getName(); 84 85 // ------------------------------------------------------- FileItem methods 86 87 /** 88 * Provides a hint as to whether or not the file contents will be read 89 * from memory. 90 * 91 * @return <code>true</code> if the file contents will be read from memory; 92 * <code>false</code> otherwise. 93 */ 94 boolean isInMemory(); 95 96 /** 97 * Returns the size of the file item. 98 * 99 * @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 }