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, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18 package org.apache.hadoop.fs;
19
20 import java.io;
21
22 /** Utility that wraps a {@link FSInputStream} in a {@link DataInputStream}
23 * and buffers input through a {@link BufferedInputStream}. */
24 public class FSDataInputStream extends DataInputStream
25 implements Seekable, PositionedReadable {
26
27 public FSDataInputStream(InputStream in)
28 throws IOException {
29 super(in);
30 if( !(in instanceof Seekable) || !(in instanceof PositionedReadable) ) {
31 throw new IllegalArgumentException(
32 "In is not an instance of Seekable or PositionedReadable");
33 }
34 }
35
36 public synchronized void seek(long desired) throws IOException {
37 ((Seekable)in).seek(desired);
38 }
39
40 public long getPos() throws IOException {
41 return ((Seekable)in).getPos();
42 }
43
44 public int read(long position, byte[] buffer, int offset, int length)
45 throws IOException {
46 return ((PositionedReadable)in).read(position, buffer, offset, length);
47 }
48
49 public void readFully(long position, byte[] buffer, int offset, int length)
50 throws IOException {
51 ((PositionedReadable)in).readFully(position, buffer, offset, length);
52 }
53
54 public void readFully(long position, byte[] buffer)
55 throws IOException {
56 ((PositionedReadable)in).readFully(position, buffer, 0, buffer.length);
57 }
58
59 public boolean seekToNewSource(long targetPos) throws IOException {
60 return ((Seekable)in).seekToNewSource(targetPos);
61 }
62 }
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