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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.fileupload2.core;
18  
19  import java.io.IOException;
20  import java.io.InputStream;
21  
22  /**
23   * Provides access to a file or form item that was received within a {@code multipart/form-data} POST request.
24   * <p>
25   * The items contents are retrieved by calling {@link #getInputStream()}.
26   * </p>
27   * <p>
28   * Instances of this class are created by accessing the iterator, returned by {@link AbstractFileUpload#getItemIterator(RequestContext)}.
29   * </p>
30   * <p>
31   * <em>Note</em>: There is an interaction between the iterator and its associated instances of {@link FileItemInput}: By invoking
32   * {@link java.util.Iterator#hasNext()} on the iterator, you discard all data, which hasn't been read so far from the previous data.
33   * </p>
34   */
35  public interface FileItemInput extends FileItemHeadersProvider<FileItemInput> {
36  
37      /**
38       * This exception is thrown, if an attempt is made to read data from the {@link InputStream}, which has been returned by
39       * {@link FileItemInput#getInputStream()}, after {@link java.util.Iterator#hasNext()} has been invoked on the iterator, which created the
40       * {@link FileItemInput}.
41       */
42      class ItemSkippedException extends FileUploadException {
43  
44          /**
45           * The exceptions serial version UID, which is being used when serializing an exception instance.
46           */
47          private static final long serialVersionUID = 2;
48  
49          /**
50           * Constructs an instance with a given detail message.
51           *
52           * @param message The detail message (which is saved for later retrieval by the {@link #getMessage()} method)
53           */
54          ItemSkippedException(final String message) {
55              super(message);
56          }
57  
58      }
59  
60      /**
61       * Gets the content type passed by the browser or {@code null} if not defined.
62       *
63       * @return The content type passed by the browser or {@code null} if not defined.
64       */
65      String getContentType();
66  
67      /**
68       * Gets the name of the field in the multipart form corresponding to this file item.
69       *
70       * @return The name of the form field.
71       */
72      String getFieldName();
73  
74      /**
75       * Opens an {@link InputStream}, which allows to read the items contents.
76       *
77       * @return The input stream, from which the items data may be read.
78       * @throws IllegalStateException The method was already invoked on this item. It is not possible to recreate the data stream.
79       * @throws IOException           An I/O error occurred.
80       * @see ItemSkippedException
81       */
82      InputStream getInputStream() throws IOException;
83  
84      /**
85       * Gets the original file name in the client's file system, as provided by the browser (or other client software). In most cases, this will be the base file
86       * name, without path information. However, some clients, such as the Opera browser, do include path information.
87       *
88       * @return The original file name in the client's file system.
89       */
90      String getName();
91  
92      /**
93       * Tests whether or not a {@code FileItem} instance represents a simple form field.
94       *
95       * @return {@code true} if the instance represents a simple form field; {@code false} if it represents an uploaded file.
96       */
97      boolean isFormField();
98  
99  }