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
18
19 package org.apache.tomcat.util.http.fileupload;
20
21
22 import java.io.File;
23 import java.io.IOException;
24 import java.io.InputStream;
25 import java.io.OutputStream;
26 import java.io.Serializable;
27 import java.io.UnsupportedEncodingException;
28
29
30 /**
31 * <p> This class represents a file or form item that was received within a
32 * <code>multipart/form-data</code> POST request.
33 *
34 * <p> After retrieving an instance of this class from a {@link
35 * org.apache.tomcat.util.http.fileupload.FileUpload FileUpload} instance (see
36 * {@link org.apache.tomcat.util.http.fileupload.FileUpload
37 * #parseRequest(javax.servlet.http.HttpServletRequest)}), you may
38 * either request all contents of the file at once using {@link #get()} or
39 * request an {@link java.io.InputStream InputStream} with
40 * {@link #getInputStream()} and process the file without attempting to load
41 * it into memory, which may come handy with large files.
42 *
43 * <p> While this interface does not extend
44 * <code>javax.activation.DataSource</code> per se (to avoid a seldom used
45 * dependency), several of the defined methods are specifically defined with
46 * the same signatures as methods in that interface. This allows an
47 * implementation of this interface to also implement
48 * <code>javax.activation.DataSource</code> with minimal additional work.
49 *
50 * @author <a href="mailto:Rafal.Krzewski@e-point.pl">Rafal Krzewski</a>
51 * @author <a href="mailto:sean@informage.net">Sean Legassick</a>
52 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
53 * @author <a href="mailto:martinc@apache.org">Martin Cooper</a>
54 *
55 * @version $Id: FileItem.java 467222 2006-10-24 03:17:11Z markt $
56 */
57 public interface FileItem
58 extends Serializable
59 {
60
61
62 // ------------------------------- Methods from javax.activation.DataSource
63
64
65 /**
66 * Returns an {@link java.io.InputStream InputStream} that can be
67 * used to retrieve the contents of the file.
68 *
69 * @return An {@link java.io.InputStream InputStream} that can be
70 * used to retrieve the contents of the file.
71 *
72 * @exception IOException if an error occurs.
73 */
74 InputStream getInputStream()
75 throws IOException;
76
77
78 /**
79 * Returns the content type passed by the browser or <code>null</code> if
80 * not defined.
81 *
82 * @return The content type passed by the browser or <code>null</code> if
83 * not defined.
84 */
85 String getContentType();
86
87
88 /**
89 * Returns the original filename in the client's filesystem, as provided by
90 * the browser (or other client software). In most cases, this will be the
91 * base file name, without path information. However, some clients, such as
92 * the Opera browser, do include path information.
93 *
94 * @return The original filename in the client's filesystem.
95 */
96 String getName();
97
98
99 // ------------------------------------------------------- FileItem methods
100
101
102 /**
103 * Provides a hint as to whether or not the file contents will be read
104 * from memory.
105 *
106 * @return <code>true</code> if the file contents will be read from memory;
107 * <code>false</code> otherwise.
108 */
109 boolean isInMemory();
110
111
112 /**
113 * Returns the size of the file item.
114 *
115 * @return The size of the file item, in bytes.
116 */
117 long getSize();
118
119
120 /**
121 * Returns the contents of the file item as an array of bytes.
122 *
123 * @return The contents of the file item as an array of bytes.
124 */
125 byte[] get();
126
127
128 /**
129 * Returns the contents of the file item as a String, using the specified
130 * encoding. This method uses {@link #get()} to retrieve the
131 * contents of the item.
132 *
133 * @param encoding The character encoding to use.
134 *
135 * @return The contents of the item, as a string.
136 *
137 * @exception UnsupportedEncodingException if the requested character
138 * encoding is not available.
139 */
140 String getString(String encoding)
141 throws UnsupportedEncodingException;
142
143
144 /**
145 * Returns the contents of the file item as a String, using the default
146 * character encoding. This method uses {@link #get()} to retrieve the
147 * contents of the item.
148 *
149 * @return The contents of the item, as a string.
150 */
151 String getString();
152
153
154 /**
155 * A convenience method to write an uploaded item to disk. The client code
156 * is not concerned with whether or not the item is stored in memory, or on
157 * disk in a temporary location. They just want to write the uploaded item
158 * to a file.
159 * <p>
160 * This method is not guaranteed to succeed if called more than once for
161 * the same item. This allows a particular implementation to use, for
162 * example, file renaming, where possible, rather than copying all of the
163 * underlying data, thus gaining a significant performance benefit.
164 *
165 * @param file The <code>File</code> into which the uploaded item should
166 * be stored.
167 *
168 * @exception Exception if an error occurs.
169 */
170 void write(File file) throws Exception;
171
172
173 /**
174 * Deletes the underlying storage for a file item, including deleting any
175 * associated temporary disk file. Although this storage will be deleted
176 * automatically when the <code>FileItem</code> instance is garbage
177 * collected, this method can be used to ensure that this is done at an
178 * earlier time, thus preserving system resources.
179 */
180 void delete();
181
182
183 /**
184 * Returns the name of the field in the multipart form corresponding to
185 * this file item.
186 *
187 * @return The name of the form field.
188 */
189 String getFieldName();
190
191
192 /**
193 * Sets the field name used to reference this file item.
194 *
195 * @param name The name of the form field.
196 */
197 void setFieldName(String name);
198
199
200 /**
201 * Determines whether or not a <code>FileItem</code> instance represents
202 * a simple form field.
203 *
204 * @return <code>true</code> if the instance represents a simple form
205 * field; <code>false</code> if it represents an uploaded file.
206 */
207 boolean isFormField();
208
209
210 /**
211 * Specifies whether or not a <code>FileItem</code> instance represents
212 * a simple form field.
213 *
214 * @param state <code>true</code> if the instance represents a simple form
215 * field; <code>false</code> if it represents an uploaded file.
216 */
217 void setFormField(boolean state);
218
219
220 /**
221 * Returns an {@link java.io.OutputStream OutputStream} that can
222 * be used for storing the contents of the file.
223 *
224 * @return An {@link java.io.OutputStream OutputStream} that can be used
225 * for storing the contensts of the file.
226 *
227 * @exception IOException if an error occurs.
228 */
229 OutputStream getOutputStream() throws IOException;
230
231 }