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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.IOException;
20  import java.io.InputStream;
21  
22  /**
23   * <p> This interface provides access to a file or form item that was
24   * received within a {@code multipart/form-data} POST request.
25   * The items contents are retrieved by calling {@link #openStream()}.</p>
26   * <p>Instances of this class are created by accessing the
27   * iterator, returned by
28   * {@link FileUploadBase#getItemIterator(RequestContext)}.</p>
29   * <p><em>Note</em>: There is an interaction between the iterator and
30   * its associated instances of {@link FileItemStream}: By invoking
31   * {@link java.util.Iterator#hasNext()} on the iterator, you discard all data,
32   * which hasn't been read so far from the previous data.</p>
33   */
34  public interface FileItemStream extends FileItemHeadersSupport {
35  
36      /**
37       * This exception is thrown, if an attempt is made to read
38       * data from the {@link InputStream}, which has been returned
39       * by {@link FileItemStream#openStream()}, after
40       * {@link java.util.Iterator#hasNext()} has been invoked on the
41       * iterator, which created the {@link FileItemStream}.
42       */
43      class ItemSkippedException extends IOException {
44  
45          /**
46           * The exceptions serial version UID, which is being used
47           * when serializing an exception instance.
48           */
49          private static final long serialVersionUID = -7280778431581963740L;
50  
51          /**
52           * Constructs a new instance.
53           */
54          public ItemSkippedException() {
55              // empty
56          }
57  
58      }
59  
60      /**
61       * Returns the content type passed by the browser or {@code null} if
62       * not defined.
63       *
64       * @return The content type passed by the browser or {@code null} if
65       *         not defined.
66       */
67      String getContentType();
68  
69      /**
70       * Returns the name of the field in the multipart form corresponding to
71       * this file item.
72       *
73       * @return The name of the form field.
74       */
75      String getFieldName();
76  
77      /**
78       * Returns the original file name in the client's file system, as provided by
79       * the browser (or other client software). In most cases, this will be the
80       * base file name, without path information. However, some clients, such as
81       * the Opera browser, do include path information.
82       *
83       * @return The original file name in the client's file system.
84       */
85      String getName();
86  
87      /**
88       * Determines whether or not a {@code FileItem} instance represents
89       * a simple form field.
90       *
91       * @return {@code true} if the instance represents a simple form
92       *         field; {@code false} if it represents an uploaded file.
93       */
94      boolean isFormField();
95  
96      /**
97       * Creates an {@link InputStream}, which allows to read the
98       * items contents.
99       *
100      * @return The input stream, from which the items data may
101      *   be read.
102      * @throws IllegalStateException The method was already invoked on
103      * this item. It is not possible to recreate the data stream.
104      * @throws IOException An I/O error occurred.
105      * @see ItemSkippedException
106      */
107     InputStream openStream() throws IOException;
108 
109 }