1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.myfaces.trinidad.webapp;
20
21 import java.io.IOException;
22 import org.apache.myfaces.trinidad.model.UploadedFile;
23
24 /**
25 * Marker Interface responsible for processing file uploads by multiple processors
26 * one after another in a chained fashion. An Apache Trinidad application could have
27 * multiple <code>ChainedUploadedFileProcessor</code> instances. A composite UploadedFileProcessor
28 * is accessible from the {@link org.apache.myfaces.trinidad.context.RequestContext},
29 * but will be invoked automatically by the framework as needed. Developers
30 * can implement this interface and chain many of them up together using space
31 * separated class names in <code>trinidad-config.xml</code> file under
32 * <code>uploaded-file-processor</code> element. The order in which the processors
33 * will be instantated and called will be the same as how it appears inside the element.
34 * As such, it is expected that the input of the ChainedUploadedFileProcessor will be
35 * the output of the last ChainedUploadedFileProcessor.
36 * <p/>
37 * UploadedFileProcessors which implement this interface are subject to the following
38 * limitations/abilities:
39 * <ul>
40 * <li>
41 * Unlike in the <code>UploadedFileProcessor</code> the {@link UploadedFile} objects given
42 * to a chained UploadedFileProcessor should allow for multiple reads such that
43 * {@link UploadedFile#getInputStream()} may be called multiple times and must return a
44 * new <code>InputStream</code> every time it is called.
45 * </li>
46 * <li>
47 * Chained processors need not return new <code>UploadedFile</code> instances. They may,
48 * instead, return the same instance as its predecessor, thus saving the need to move
49 * content around with each call into the chain. If a <code>ChainedUploadedFileProcessor</code>
50 * DOES return a new instance of UploadedFile, it must be allowed to be read multiple times.
51 * </li>
52 * <li>
53 * Chained processors may extend the {@link ExtendedUploadedFileProcessor} abstract
54 * class. Any additional methods will be handled in accordance to the modifications listed above.
55 * </li>
56 * </ul>
57 *
58 * @see org.apache.myfaces.trinidad.model.UploadedFile
59 */
60 public interface ChainedUploadedFileProcessor extends UploadedFileProcessor {}