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 OutputStream} in a {@link DataOutputStream}, |
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23 | * buffers output through a {@link BufferedOutputStream} and creates a checksum |
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24 | * file. */ |
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25 | public class FSDataOutputStream extends DataOutputStream implements Syncable { |
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26 | private OutputStream wrappedStream; |
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27 | |
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28 | private static class PositionCache extends FilterOutputStream { |
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29 | private FileSystem.Statistics statistics; |
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30 | long position; |
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31 | |
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32 | public PositionCache(OutputStream out, |
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33 | FileSystem.Statistics stats, |
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34 | long pos) throws IOException { |
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35 | super(out); |
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36 | statistics = stats; |
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37 | position = pos; |
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38 | } |
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39 | |
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40 | public void write(int b) throws IOException { |
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41 | out.write(b); |
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42 | position++; |
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43 | if (statistics != null) { |
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44 | statistics.incrementBytesWritten(1); |
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45 | } |
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46 | } |
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47 | |
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48 | public void write(byte b[], int off, int len) throws IOException { |
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49 | out.write(b, off, len); |
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50 | position += len; // update position |
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51 | if (statistics != null) { |
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52 | statistics.incrementBytesWritten(len); |
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53 | } |
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54 | } |
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55 | |
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56 | public long getPos() throws IOException { |
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57 | return position; // return cached position |
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58 | } |
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59 | |
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60 | public void close() throws IOException { |
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61 | out.close(); |
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62 | } |
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63 | } |
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64 | |
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65 | @Deprecated |
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66 | public FSDataOutputStream(OutputStream out) throws IOException { |
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67 | this(out, null); |
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68 | } |
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69 | |
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70 | public FSDataOutputStream(OutputStream out, FileSystem.Statistics stats) |
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71 | throws IOException { |
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72 | this(out, stats, 0); |
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73 | } |
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74 | |
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75 | public FSDataOutputStream(OutputStream out, FileSystem.Statistics stats, |
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76 | long startPosition) throws IOException { |
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77 | super(new PositionCache(out, stats, startPosition)); |
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78 | wrappedStream = out; |
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79 | } |
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80 | |
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81 | public long getPos() throws IOException { |
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82 | return ((PositionCache)out).getPos(); |
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83 | } |
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84 | |
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85 | public void close() throws IOException { |
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86 | out.close(); // This invokes PositionCache.close() |
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87 | } |
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88 | |
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89 | // Returns the underlying output stream. This is used by unit tests. |
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90 | public OutputStream getWrappedStream() { |
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91 | return wrappedStream; |
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92 | } |
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93 | |
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94 | /** {@inheritDoc} */ |
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95 | public void sync() throws IOException { |
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96 | if (wrappedStream instanceof Syncable) { |
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97 | ((Syncable)wrappedStream).sync(); |
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98 | } |
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99 | } |
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100 | } |
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