[120] | 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 org.apache.hadoop.conf.Configuration; |
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| 21 | import org.apache.hadoop.util.Shell; |
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| 22 | |
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| 23 | import java.io.BufferedReader; |
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| 24 | import java.io.File; |
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| 25 | import java.io.IOException; |
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| 26 | import java.util.concurrent.atomic.AtomicLong; |
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| 27 | |
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| 28 | /** Filesystem disk space usage statistics. Uses the unix 'du' program*/ |
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| 29 | public class DU extends Shell { |
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| 30 | private String dirPath; |
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| 31 | |
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| 32 | private AtomicLong used = new AtomicLong(); |
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| 33 | private volatile boolean shouldRun = true; |
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| 34 | private Thread refreshUsed; |
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| 35 | private IOException duException = null; |
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| 36 | private long refreshInterval; |
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| 37 | |
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| 38 | /** |
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| 39 | * Keeps track of disk usage. |
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| 40 | * @param path the path to check disk usage in |
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| 41 | * @param interval refresh the disk usage at this interval |
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| 42 | * @throws IOException if we fail to refresh the disk usage |
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| 43 | */ |
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| 44 | public DU(File path, long interval) throws IOException { |
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| 45 | super(0); |
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| 46 | |
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| 47 | //we set the Shell interval to 0 so it will always run our command |
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| 48 | //and use this one to set the thread sleep interval |
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| 49 | this.refreshInterval = interval; |
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| 50 | this.dirPath = path.getCanonicalPath(); |
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| 51 | |
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| 52 | //populate the used variable |
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| 53 | run(); |
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| 54 | } |
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| 55 | |
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| 56 | /** |
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| 57 | * Keeps track of disk usage. |
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| 58 | * @param path the path to check disk usage in |
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| 59 | * @param conf configuration object |
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| 60 | * @throws IOException if we fail to refresh the disk usage |
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| 61 | */ |
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| 62 | public DU(File path, Configuration conf) throws IOException { |
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| 63 | this(path, 600000L); |
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| 64 | //10 minutes default refresh interval |
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| 65 | } |
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| 66 | |
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| 67 | /** |
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| 68 | * This thread refreshes the "used" variable. |
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| 69 | * |
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| 70 | * Future improvements could be to not permanently |
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| 71 | * run this thread, instead run when getUsed is called. |
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| 72 | **/ |
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| 73 | class DURefreshThread implements Runnable { |
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| 74 | |
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| 75 | public void run() { |
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| 76 | |
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| 77 | while(shouldRun) { |
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| 78 | |
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| 79 | try { |
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| 80 | Thread.sleep(refreshInterval); |
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| 81 | |
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| 82 | try { |
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| 83 | //update the used variable |
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| 84 | DU.this.run(); |
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| 85 | } catch (IOException e) { |
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| 86 | synchronized (DU.this) { |
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| 87 | //save the latest exception so we can return it in getUsed() |
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| 88 | duException = e; |
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| 89 | } |
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| 90 | |
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| 91 | LOG.warn("Could not get disk usage information", e); |
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| 92 | } |
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| 93 | } catch (InterruptedException e) { |
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| 94 | } |
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| 95 | } |
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| 96 | } |
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| 97 | } |
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| 98 | |
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| 99 | /** |
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| 100 | * Decrease how much disk space we use. |
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| 101 | * @param value decrease by this value |
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| 102 | */ |
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| 103 | public void decDfsUsed(long value) { |
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| 104 | used.addAndGet(-value); |
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| 105 | } |
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| 106 | |
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| 107 | /** |
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| 108 | * Increase how much disk space we use. |
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| 109 | * @param value increase by this value |
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| 110 | */ |
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| 111 | public void incDfsUsed(long value) { |
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| 112 | used.addAndGet(value); |
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| 113 | } |
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| 114 | |
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| 115 | /** |
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| 116 | * @return disk space used |
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| 117 | * @throws IOException if the shell command fails |
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| 118 | */ |
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| 119 | public long getUsed() throws IOException { |
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| 120 | //if the updating thread isn't started, update on demand |
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| 121 | if(refreshUsed == null) { |
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| 122 | run(); |
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| 123 | } else { |
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| 124 | synchronized (DU.this) { |
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| 125 | //if an exception was thrown in the last run, rethrow |
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| 126 | if(duException != null) { |
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| 127 | IOException tmp = duException; |
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| 128 | duException = null; |
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| 129 | throw tmp; |
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| 130 | } |
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| 131 | } |
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| 132 | } |
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| 133 | |
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| 134 | return used.longValue(); |
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| 135 | } |
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| 136 | |
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| 137 | /** |
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| 138 | * @return the path of which we're keeping track of disk usage |
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| 139 | */ |
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| 140 | public String getDirPath() { |
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| 141 | return dirPath; |
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| 142 | } |
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| 143 | |
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| 144 | /** |
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| 145 | * Start the disk usage checking thread. |
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| 146 | */ |
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| 147 | public void start() { |
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| 148 | //only start the thread if the interval is sane |
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| 149 | if(refreshInterval > 0) { |
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| 150 | refreshUsed = new Thread(new DURefreshThread(), |
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| 151 | "refreshUsed-"+dirPath); |
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| 152 | refreshUsed.setDaemon(true); |
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| 153 | refreshUsed.start(); |
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| 154 | } |
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| 155 | } |
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| 156 | |
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| 157 | /** |
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| 158 | * Shut down the refreshing thread. |
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| 159 | */ |
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| 160 | public void shutdown() { |
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| 161 | this.shouldRun = false; |
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| 162 | |
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| 163 | if(this.refreshUsed != null) { |
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| 164 | this.refreshUsed.interrupt(); |
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| 165 | } |
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| 166 | } |
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| 167 | |
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| 168 | public String toString() { |
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| 169 | return |
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| 170 | "du -sk " + dirPath +"\n" + |
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| 171 | used + "\t" + dirPath; |
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| 172 | } |
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| 173 | |
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| 174 | protected String[] getExecString() { |
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| 175 | return new String[] {"du", "-sk", dirPath}; |
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| 176 | } |
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| 177 | |
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| 178 | protected void parseExecResult(BufferedReader lines) throws IOException { |
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| 179 | String line = lines.readLine(); |
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| 180 | if (line == null) { |
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| 181 | throw new IOException("Expecting a line not the end of stream"); |
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| 182 | } |
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| 183 | String[] tokens = line.split("\t"); |
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| 184 | if(tokens.length == 0) { |
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| 185 | throw new IOException("Illegal du output"); |
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| 186 | } |
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| 187 | this.used.set(Long.parseLong(tokens[0])*1024); |
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| 188 | } |
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| 189 | |
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| 190 | public static void main(String[] args) throws Exception { |
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| 191 | String path = "."; |
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| 192 | if (args.length > 0) { |
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| 193 | path = args[0]; |
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| 194 | } |
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| 195 | |
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| 196 | System.out.println(new DU(new File(path), new Configuration()).toString()); |
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| 197 | } |
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| 198 | } |
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