1 /*
2 * dpkg - Debian Package library and the Debian Package Maven plugin
3 * (c) Copyright 2015 Gerrit Hohl
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version 2
8 * of the License, or (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 */
19 package net.sourceforge.javadpkg.io;
20
21 import java.io.Closeable;
22 import java.io.IOException;
23 import java.io.InputStream;
24
25 /**
26 * <p>
27 * The source for reading data.
28 * </p>
29 *
30 * @author Gerrit Hohl (gerrit-hohl@users.sourceforge.net)
31 * @version <b>1.0</b>, 31.12.2015 by Gerrit Hohl
32 */
33 public interface DataSource extends Closeable {
34
35
36 /**
37 * <p>
38 * Returns the name of the source.
39 * </p>
40 * <p>
41 * This name is used e.g. for detail messages of exceptions.
42 * </p>
43 *
44 * @return The name.
45 */
46 String getName();
47
48
49 /**
50 * <p>
51 * Returns the length of the data which can be read from the source in
52 * bytes.
53 * </p>
54 *
55 * @return The length or <code>-1</code>, if the length is unknown.
56 */
57 long getLength();
58
59
60 /**
61 * <p>
62 * Returns the flag if the source can be reseted.
63 * </p>
64 *
65 * @return The flag: <code>true</code>, if the source can be reseted,
66 * <code>false</code> otherwise.
67 * @see #reset()
68 */
69 boolean isResettable();
70
71
72 /**
73 * <p>
74 * Resets the source.
75 * </p>
76 * <p>
77 * If the source can't be reseted an {@link IOException} will be thrown.
78 * </p>
79 * <p>
80 * If the source can be reseted the next call of the
81 * {@link #getInputStream()} method will return a new {@link InputStream}
82 * which reads the source from the beginning again.
83 * </p>
84 *
85 * @throws IOException
86 * If an I/O error occurs or if the source doesn't support a
87 * reset.
88 * @see #isResettable()
89 */
90 void reset() throws IOException;
91
92
93 /**
94 * <p>
95 * Returns a stream for reading the data.
96 * </p>
97 * <p>
98 * The method will always return the same {@link InputStream} if the source
99 * is still open. If the {@link InputStream#close()} method is called the
100 * source will behave the same as the {@link #close()} method was called.
101 * </p>
102 * <p>
103 * If the {@link #reset()} method was successfully called the method will
104 * return a different {@link InputStream}.
105 * </p>
106 *
107 * @return The stream.
108 * @throws IOException
109 * If an I/O error occurs.
110 */
111 InputStream getInputStream() throws IOException;
112
113
114 }