1 | /** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one |
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3 | * or more contributor license agreements. See the NOTICE file |
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4 | * distributed with this work for additional information |
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5 | * regarding copyright ownership. The ASF licenses this file |
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6 | * to you under the Apache License, Version 2.0 (the |
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7 | * "License"); you may not use this file except in compliance |
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8 | * with the License. You may obtain a copy of the License at |
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9 | * |
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10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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11 | * |
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12 | * Unless required by applicable law or agreed to in writing, software |
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13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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15 | * See the License for the specific language governing permissions and |
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16 | * limitations under the License. |
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17 | */ |
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18 | package org.apache.hadoop.fs; |
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19 | |
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20 | import java.io.*; |
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21 | |
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22 | /** Utility that wraps a {@link FSInputStream} in a {@link DataInputStream} |
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23 | * and buffers input through a {@link BufferedInputStream}. */ |
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24 | public class FSDataInputStream extends DataInputStream |
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25 | implements Seekable, PositionedReadable { |
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26 | |
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27 | public FSDataInputStream(InputStream in) |
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28 | throws IOException { |
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29 | super(in); |
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30 | if( !(in instanceof Seekable) || !(in instanceof PositionedReadable) ) { |
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31 | throw new IllegalArgumentException( |
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32 | "In is not an instance of Seekable or PositionedReadable"); |
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33 | } |
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34 | } |
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35 | |
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36 | public synchronized void seek(long desired) throws IOException { |
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37 | ((Seekable)in).seek(desired); |
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38 | } |
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39 | |
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40 | public long getPos() throws IOException { |
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41 | return ((Seekable)in).getPos(); |
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42 | } |
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43 | |
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44 | public int read(long position, byte[] buffer, int offset, int length) |
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45 | throws IOException { |
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46 | return ((PositionedReadable)in).read(position, buffer, offset, length); |
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47 | } |
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48 | |
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49 | public void readFully(long position, byte[] buffer, int offset, int length) |
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50 | throws IOException { |
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51 | ((PositionedReadable)in).readFully(position, buffer, offset, length); |
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52 | } |
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53 | |
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54 | public void readFully(long position, byte[] buffer) |
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55 | throws IOException { |
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56 | ((PositionedReadable)in).readFully(position, buffer, 0, buffer.length); |
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57 | } |
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58 | |
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59 | public boolean seekToNewSource(long targetPos) throws IOException { |
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60 | return ((Seekable)in).seekToNewSource(targetPos); |
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61 | } |
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62 | } |
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