Beispiel #1
0
  public static void main(String[] args) throws Exception {
    String inputDirectory = "/home/cs246/Desktop/HW2/input";
    String outputDirectory = "/home/cs246/Desktop/HW2/output";
    String centroidDirectory = "/home/cs246/Desktop/HW2/config";

    int iterations = 20;

    for (int i = 1; i <= iterations; i++) {
      Configuration conf = new Configuration();

      String cFile = centroidDirectory + "/c" + i + ".txt";
      String nextCFile = centroidDirectory + "/c" + (i + 1) + ".txt";
      conf.set("CFILE", cFile);
      conf.set("NEXTCFILE", nextCFile);

      String cFile = centroidDirectory + "/c" + i + ".txt";
      String nextCFile = centroidDirectory + "/c" + (i + 1) + ".txt";
      conf.set("CFILE", cFile);
      conf.set("NEXTCFILE", nextCFile);

      Job job = new Job(conf, "HW2_Q4." + i);
      job.setJarByClass(HW2_Q4.class);
      job.setOutputKeyClass(IntWritable.class);
      job.setOutputValueClass(Text.class);
      job.setMapperClass(Map1.class);
      job.setReducerClass(Reduce1.class);
      job.setInputFormatClass(TextInputFormat.class);
      job.setOutputFormatClass(TextOutputFormat.class);

      FileInputFormat.addInputPath(job, new Path(inputDirectory));
      FileOutputFormat.setOutputPath(job, new Path(outputDirectory + "/output" + i));

      job.waitForCompletion(true);
    }
  }
  public int run(String[] args) throws Exception {
    Configuration argConf = getConf();

    // JobConf conf = new JobConf(diffdb.class);
    Configuration config = HBaseConfiguration.create();
    HBaseAdmin hbAdmin = new HBaseAdmin(config);
    dbutil db_util = new dbutil(config);

    HTable runTable = new HTable(config, "gestore_runs");
    Get runGet = new Get(argConf.get("id").getBytes());
    Result pipeline = runTable.get(runGet);

    NavigableMap<byte[], byte[]> pipeMap = pipeline.getFamilyMap("d".getBytes());

    Map.Entry<byte[], byte[]> results = pipeMap.pollFirstEntry();

    HashMap<String, HashMap<String, String>> resultMap =
        new HashMap<String, HashMap<String, String>>();

    while (results != null) {
      String resultKey = new String(results.getKey());
      String resultValue = new String(results.getValue());
      String field = "type";
      HashMap<String, String> tempMap = new HashMap<String, String>();
      String entry = resultKey;

      if (resultKey.endsWith("_db_timestamp")) {
        field = "db_timestamp";
        entry = resultKey.substring(0, resultKey.lastIndexOf("_db_timestamp"));
      } else if (resultKey.endsWith("_filename")) {
        field = "filename";
        entry = resultKey.substring(0, resultKey.lastIndexOf("_filename"));
      } else if (resultKey.endsWith("_regex")) {
        field = "regex";
        entry = resultKey.substring(0, resultKey.lastIndexOf("_regex"));
      }

      if (resultMap.containsKey(entry)) {
        tempMap = resultMap.get(entry);
      }

      tempMap.put(field, resultValue);
      resultMap.put(entry, tempMap);

      // System.out.println("Key: " + resultKey + " Value: " + resultValue);
      results = pipeMap.pollFirstEntry();
    }

    for (String key : resultMap.keySet()) {
      System.out.println("File ID: " + key);
      for (String subKey : resultMap.get(key).keySet()) {
        // System.out.println("\t " + subKey + "\t\t" + resultMap.get(key).get(subKey));
        System.out.format("  %1$-20s  %2$s\n", subKey, resultMap.get(key).get(subKey));
      }
    }

    return 0;
  }
Beispiel #3
0
 private static String getConfigString(Configuration config) {
   String output = "";
   Iterator<Map.Entry<String, String>> iterConfig = config.iterator();
   while (iterConfig.hasNext()) {
     Map.Entry<String, String> curEntry = iterConfig.next();
     output = output + "Key: \t" + curEntry.getKey() + "\nValue: \t" + curEntry.getValue() + "\n";
   }
   return output;
 }
Beispiel #4
0
 // return the RpcEngine configured to handle a protocol
 static synchronized RpcEngine getProtocolEngine(Class<?> protocol, Configuration conf) {
   RpcEngine engine = PROTOCOL_ENGINES.get(protocol);
   if (engine == null) {
     Class<?> impl =
         conf.getClass(ENGINE_PROP + "." + protocol.getName(), WritableRpcEngine.class);
     engine = (RpcEngine) ReflectionUtils.newInstance(impl, conf);
     PROTOCOL_ENGINES.put(protocol, engine);
   }
   return engine;
 }
  public static void main(String[] args) throws Exception {
    Configuration conf = new Configuration();
    FileSystem fs = FileSystem.get(conf);

    Path matFile = new Path(args[0]);
    FSDataInputStream matData = fs.open(matFile);
    BufferedReader br = new BufferedReader(new InputStreamReader(matData));

    int i = 0;
    String line;
    while ((line = br.readLine()) != null) {
      StringTokenizer tokenizer = new StringTokenizer(line);
      String iRow = tokenizer.nextToken();
      String iCol = tokenizer.nextToken();
      if (Integer.parseInt(iRow) == Integer.parseInt(iCol)) {
        i++;
      }
    }
    br.close();
    int dimention = i;

    conf.setInt("DIMENTION", dimention);
    Path xFile = new Path("preX/Result");
    FSDataOutputStream xData = fs.create(xFile);
    BufferedWriter iniX = new BufferedWriter(new OutputStreamWriter(xData));
    for (int j = 0; j < dimention; j++) {
      iniX.write(String.valueOf(j) + " 0");
      iniX.newLine();
    }
    iniX.close();

    URI matVec = new URI(args[0]);
    DistributedCache.addCacheFile(matVec, conf);

    int iteration = 0;
    do {
      ToolRunner.run(conf, new Jacobi(), args);
    } while (iteration++ < max_iter && (!stopIteration(conf)));
  }
  /**
   * @param args
   * @throws IOException
   * @throws ClassNotFoundException
   * @throws InterruptedException
   */
  public static void main(String[] args)
      throws IOException, InterruptedException, ClassNotFoundException {
    // TODO Auto-generated method stub

    Configuration conf = new Configuration();
    conf.set("inParameter", toString(args));
    Job job = new Job(conf, "MovieGenreIdentifier");

    job.setOutputKeyClass(Text.class);
    job.setOutputValueClass(IntWritable.class);
    job.setJarByClass(MovieGenreIdentifier.class);
    job.setMapperClass(Map.class);
    job.setCombinerClass(Reduce.class);
    job.setReducerClass(Reduce.class);

    job.setInputFormatClass(TextInputFormat.class);
    job.setOutputFormatClass(TextOutputFormat.class);

    FileInputFormat.addInputPath(job, new Path(args[0]));
    FileOutputFormat.setOutputPath(job, new Path(args[1]));

    job.waitForCompletion(true);
  }
Beispiel #7
0
 /**
  * Construct an RPC server.
  *
  * @param instance the instance whose methods will be called
  * @param conf the configuration to use
  * @param bindAddress the address to bind on to listen for connection
  * @param port the port to listen for connections on
  * @param numHandlers the number of method handler threads to run
  * @param verbose whether each call should be logged
  * @param supportOldJobConf supports server to deserialize old job conf
  */
 public Server(
     Object instance,
     Configuration conf,
     String bindAddress,
     int port,
     int numHandlers,
     boolean verbose,
     boolean supportOldJobConf)
     throws IOException {
   super(
       bindAddress,
       port,
       Invocation.class,
       numHandlers,
       conf,
       classNameBase(instance.getClass().getName()),
       supportOldJobConf);
   this.instance = instance;
   this.verbose = verbose;
   this.authorize =
       conf.getBoolean(ServiceAuthorizationManager.SERVICE_AUTHORIZATION_CONFIG, false);
 }
  @Override
  public int run(String[] args) throws Exception {

    String locatorHost = args[0];
    int locatorPort = Integer.parseInt(args[1]);
    String hdfsHomeDir = args[2];

    System.out.println(
        "KnownKeysMRv2 invoked with args (locatorHost = "
            + locatorHost
            + " locatorPort = "
            + locatorPort
            + " hdfsHomeDir = "
            + hdfsHomeDir);

    Configuration conf = getConf();
    conf.set(GFInputFormat.INPUT_REGION, "partitionedRegion");
    conf.set(GFInputFormat.HOME_DIR, hdfsHomeDir);
    conf.setBoolean(GFInputFormat.CHECKPOINT, false);
    conf.set(GFOutputFormat.REGION, "validationRegion");
    conf.set(GFOutputFormat.LOCATOR_HOST, locatorHost);
    conf.setInt(GFOutputFormat.LOCATOR_PORT, locatorPort);

    Job job = Job.getInstance(conf, "knownKeysMRv2");
    job.setInputFormatClass(GFInputFormat.class);
    job.setOutputFormatClass(GFOutputFormat.class);

    job.setMapperClass(KnownKeysMRv2Mapper.class);
    job.setMapOutputKeyClass(GFKey.class);
    job.setMapOutputValueClass(PEIWritable.class);

    job.setReducerClass(KnownKeysMRv2Reducer.class);
    // job.setOutputKeyClass(String.class);
    // job.setOutputValueClass(ValueHolder.class);

    return job.waitForCompletion(false) ? 0 : 1;
  }
Beispiel #9
0
 /**
  * Set a protocol to use a non-default RpcEngine.
  *
  * @param conf configuration to use
  * @param protocol the protocol interface
  * @param engine the RpcEngine impl
  */
 public static void setProtocolEngine(Configuration conf, Class<?> protocol, Class<?> engine) {
   conf.setClass(ENGINE_PROP + "." + protocol.getName(), engine, RpcEngine.class);
 }
 protected void setup(Context context) {
   Configuration config = context.getConfiguration();
   inMovies = config.get("inParameter");
 }
Beispiel #11
0
  public int run(String[] args) throws Exception {
    // printUsage();
    /*
     * SETUP
     */
    Configuration argConf = getConf();
    Hashtable<String, String> confArg = new Hashtable<String, String>();
    setup(confArg, argConf);
    Date currentTime = new Date();
    Date endDate = new Date(new Long(confArg.get("timestamp_stop")));
    Boolean full_run = confArg.get("intermediate").matches("(?i).*true.*");
    Boolean quick_add = confArg.get("quick_add").matches("(?i).*true.*");
    logger.info("Running GeStore");

    // ZooKeeper setup
    Configuration config = HBaseConfiguration.create();
    zkWatcher = new ZooKeeperWatcher(config, "Testing", new HBaseAdmin(config));
    zkInstance =
        new ZooKeeper(
            ZKConfig.getZKQuorumServersString(config),
            config.getInt("zookeeper.session.timeout", -1),
            zkWatcher);

    if (!confArg.get("task_id").isEmpty()) {
      confArg.put("temp_path", confArg.get("temp_path") + confArg.get("task_id"));
    }

    String lockRequest = confArg.get("file_id");
    if (!confArg.get("run_id").isEmpty())
      lockRequest = lockRequest + "_" + confArg.get("run_id") + "_";
    if (!confArg.get("task_id").isEmpty())
      lockRequest = lockRequest + "_" + confArg.get("task_id") + "_";

    // Get type of movement
    toFrom type_move = checkArgs(confArg);
    if (type_move == toFrom.LOCAL2REMOTE && !confArg.get("format").equals("unknown")) {
      List<String> arguments = new ArrayList<String>();
      arguments.add("-Dinput=" + confArg.get("local_path"));
      arguments.add("-Dtable=" + confArg.get("file_id"));
      arguments.add("-Dtimestamp=" + confArg.get("timestamp_stop"));
      arguments.add("-Dtype=" + confArg.get("format"));
      arguments.add("-Dtarget_dir=" + confArg.get("base_path") + "_" + confArg.get("file_id"));
      arguments.add("-Dtemp_hdfs_path=" + confArg.get("temp_path"));
      arguments.add("-Drun_id=" + confArg.get("run_id"));
      if (!confArg.get("run_id").isEmpty()) arguments.add("-Drun_id=" + confArg.get("run_id"));
      if (!confArg.get("task_id").isEmpty()) arguments.add("-Dtask_id=" + confArg.get("task_id"));
      if (quick_add) arguments.add("-Dquick_add=" + confArg.get("quick_add"));
      String lockName = lock(lockRequest);
      String[] argumentString = arguments.toArray(new String[arguments.size()]);
      adddb.main(argumentString);
      unlock(lockName);
      System.exit(0);
    }

    // Database registration

    dbutil db_util = new dbutil(config);
    db_util.register_database(confArg.get("db_name_files"), true);
    db_util.register_database(confArg.get("db_name_runs"), true);
    db_util.register_database(confArg.get("db_name_updates"), true);
    FileSystem hdfs = FileSystem.get(config);
    FileSystem localFS = FileSystem.getLocal(config);

    // Get source type
    confArg.put("source", getSource(db_util, confArg.get("db_name_files"), confArg.get("file_id")));
    confArg.put(
        "database", isDatabase(db_util, confArg.get("db_name_files"), confArg.get("file_id")));
    if (!confArg.get("source").equals("local")
        && type_move == toFrom.REMOTE2LOCAL
        && !confArg.get("timestamp_stop").equals(Integer.toString(Integer.MAX_VALUE))) {
      confArg.put("timestamp_stop", Long.toString(latestVersion(confArg, db_util)));
    }

    /*
     * Get previous timestamp
     */
    Get run_id_get = new Get(confArg.get("run_id").getBytes());
    Result run_get = db_util.doGet(confArg.get("db_name_runs"), run_id_get);
    KeyValue run_file_prev =
        run_get.getColumnLatest(
            "d".getBytes(), (confArg.get("file_id") + "_db_timestamp").getBytes());
    String last_timestamp = new String("0");
    if (null != run_file_prev && !confArg.get("source").equals("local")) {
      long last_timestamp_real = run_file_prev.getTimestamp();
      Long current_timestamp = new Long(confArg.get("timestamp_real"));
      if ((current_timestamp - last_timestamp_real) > 36000) {
        last_timestamp = new String(run_file_prev.getValue());
        Integer lastTimestamp = new Integer(last_timestamp);
        lastTimestamp += 1;
        last_timestamp = lastTimestamp.toString();
        logger.info("Last timestamp: " + last_timestamp + " End data: " + endDate);
        Date last_run = new Date(run_file_prev.getTimestamp());
        if (last_run.before(endDate) && !full_run) {
          confArg.put("timestamp_start", last_timestamp);
        }
      }
    }

    Integer tse = new Integer(confArg.get("timestamp_stop"));
    Integer tss = new Integer(confArg.get("timestamp_start"));
    if (tss > tse) {
      logger.info("No new version of requested file.");
      return 0;
    }

    /*
     * Generate file
     */

    String lockName = lock(lockRequest);

    Get file_id_get = new Get(confArg.get("file_id").getBytes());
    Result file_get = db_util.doGet(confArg.get("db_name_files"), file_id_get);
    if (!file_get.isEmpty()) {
      boolean found =
          hasFile(
              db_util,
              hdfs,
              confArg.get("db_name_files"),
              confArg.get("file_id"),
              getFullPath(confArg));
      if (confArg.get("source").equals("fullfile")) {
        found = false;
      }
      String filenames_put =
          getFileNames(
              db_util, confArg.get("db_name_files"), confArg.get("file_id"), getFullPath(confArg));
      // Filename not found in file database
      if (!found && type_move == toFrom.REMOTE2LOCAL) {
        if (!confArg.get("source").equals("local")) {
          // Generate intermediate file
          if (getFile(hdfs, confArg, db_util) == null) {
            unlock(lockName);
            return 1;
          }
          // Put generated file into file database
          if (!confArg.get("format").equals("fullfile")) {
            putFileEntry(
                db_util,
                hdfs,
                confArg.get("db_name_files"),
                confArg.get("file_id"),
                confArg.get("full_file_name"),
                confArg.get("source"));
          }
        } else {
          logger.warn("Remote file not found, and cannot be generated! File: " + confArg);
          unlock(lockName);
          return 1;
        }
      }
    } else {
      if (type_move == toFrom.REMOTE2LOCAL) {
        logger.warn("Remote file not found, and cannot be generated.");
        unlock(lockName);
        return 1;
      }
    }

    /*
     * Copy file
     * Update tables
     */

    if (type_move == toFrom.LOCAL2REMOTE) {
      if (!confArg.get("format").equals("fullfile")) {
        putFileEntry(
            db_util,
            hdfs,
            confArg.get("db_name_files"),
            confArg.get("file_id"),
            getFullPath(confArg),
            confArg.get("source"));
      }
      putRunEntry(
          db_util,
          confArg.get("db_name_runs"),
          confArg.get("run_id"),
          confArg.get("file_id"),
          confArg.get("type"),
          confArg.get("timestamp_real"),
          confArg.get("timestamp_stop"),
          getFullPath(confArg),
          confArg.get("delimiter"));
      hdfs.copyFromLocalFile(new Path(confArg.get("local_path")), new Path(getFullPath(confArg)));
    } else if (type_move == toFrom.REMOTE2LOCAL) {
      FileStatus[] files = hdfs.globStatus(new Path(getFullPath(confArg) + "*"));
      putRunEntry(
          db_util,
          confArg.get("db_name_runs"),
          confArg.get("run_id"),
          confArg.get("file_id"),
          confArg.get("type"),
          confArg.get("timestamp_real"),
          confArg.get("timestamp_stop"),
          getFullPath(confArg),
          confArg.get("delimiter"));
      unlock(lockName);
      for (FileStatus file : files) {
        Path cur_file = file.getPath();
        Path cur_local_path =
            new Path(new String(confArg.get("local_path") + confArg.get("file_id")));
        String suffix = getSuffix(getFileName(confArg), cur_file.getName());
        if (suffix.length() > 0) {
          cur_local_path = cur_local_path.suffix(new String("." + suffix));
        }
        if (confArg.get("copy").equals("true")) {
          String crc = hdfs.getFileChecksum(cur_file).toString();
          if (checksumLocalTest(cur_local_path, crc)) {
            continue;
          } else {
            hdfs.copyToLocalFile(cur_file, cur_local_path);
            writeChecksum(cur_local_path, crc);
          }
        } else {
          System.out.println(cur_local_path + "\t" + cur_file);
        }
      }
    }
    unlock(lockName);
    return 0;
  }
Beispiel #12
0
  /** Sets up configuration based on params */
  private static boolean setup(Hashtable<String, String> curConf, Configuration argConf) {

    if (argConf.get("file") == null) {
      logger.fatal("Missing file parameter");
      System.exit(1);
    }

    if (argConf.get("hdfs_base_path") == null) {
      logger.fatal("Missing HDFS base path, check gestore-conf.xml");
      System.exit(1);
    }

    if (argConf.get("hdfs_temp_path") == null) {
      logger.fatal("Missing HDFS temp path, check gestore-conf.xml");
      System.exit(1);
    }

    if (argConf.get("local_temp_path") == null) {
      logger.fatal("Missing local temp path, check gestore-conf.xml");
      System.exit(1);
    }

    // Input paramaters
    curConf.put("run_id", argConf.get("run", ""));
    curConf.put("task_id", argConf.get("task", ""));
    curConf.put("file_id", argConf.get("file"));
    curConf.put("local_path", argConf.get("path", ""));
    curConf.put("type", argConf.get("type", "l2r"));
    curConf.put("timestamp_start", argConf.get("timestamp_start", "1"));
    curConf.put(
        "timestamp_stop", argConf.get("timestamp_stop", Integer.toString(Integer.MAX_VALUE)));
    curConf.put("delimiter", argConf.get("regex", "ID=.*"));
    curConf.put("taxon", argConf.get("taxon", "all"));
    curConf.put("intermediate", argConf.get("full_run", "false"));
    curConf.put("quick_add", argConf.get("quick_add", "false"));
    Boolean full_run = curConf.get("intermediate").matches("(?i).*true.*");
    curConf.put("format", argConf.get("format", "unknown"));
    curConf.put("split", argConf.get("split", "1"));
    curConf.put("copy", argConf.get("copy", "true"));

    // Constants
    curConf.put("base_path", argConf.get("hdfs_base_path"));
    curConf.put("temp_path", argConf.get("hdfs_temp_path"));
    curConf.put("local_temp_path", argConf.get("local_temp_path"));
    curConf.put("db_name_files", argConf.get("hbase_file_table"));
    curConf.put("db_name_runs", argConf.get("hbase_run_table"));
    curConf.put("db_name_updates", argConf.get("hbase_db_update_table"));

    // Timestamps
    Date currentTime = new Date();
    Date endDate = new Date(new Long(curConf.get("timestamp_stop")));
    curConf.put("timestamp_real", Long.toString(currentTime.getTime()));

    return true;
  }
  public void generateFileChunks(JspWriter out, HttpServletRequest req, Configuration conf)
      throws IOException, InterruptedException {
    long startOffset = 0;
    int datanodePort = 0;
    int chunkSizeToView = 0;

    String namenodeInfoPortStr = req.getParameter("namenodeInfoPort");
    int namenodeInfoPort = -1;
    if (namenodeInfoPortStr != null) namenodeInfoPort = Integer.parseInt(namenodeInfoPortStr);

    String filename = HtmlQuoting.unquoteHtmlChars(req.getParameter("filename"));
    if (filename == null) {
      out.print("Invalid input (filename absent)");
      return;
    }

    String blockIdStr = null;
    long blockId = 0;
    blockIdStr = req.getParameter("blockId");
    if (blockIdStr == null) {
      out.print("Invalid input (blockId absent)");
      return;
    }
    blockId = Long.parseLong(blockIdStr);

    String tokenString = req.getParameter(JspHelper.DELEGATION_PARAMETER_NAME);
    UserGroupInformation ugi = JspHelper.getUGI(req, conf);
    final DFSClient dfs = JspHelper.getDFSClient(ugi, jspHelper.nameNodeAddr, conf);

    Token<BlockTokenIdentifier> accessToken = BlockTokenSecretManager.DUMMY_TOKEN;
    if (conf.getBoolean(DFSConfigKeys.DFS_BLOCK_ACCESS_TOKEN_ENABLE_KEY, false)) {
      List<LocatedBlock> blks =
          dfs.namenode.getBlockLocations(filename, 0, Long.MAX_VALUE).getLocatedBlocks();
      if (blks == null || blks.size() == 0) {
        out.print("Can't locate file blocks");
        dfs.close();
        return;
      }
      for (int i = 0; i < blks.size(); i++) {
        if (blks.get(i).getBlock().getBlockId() == blockId) {
          accessToken = blks.get(i).getBlockToken();
          break;
        }
      }
    }

    String blockGenStamp = null;
    long genStamp = 0;
    blockGenStamp = req.getParameter("genstamp");
    if (blockGenStamp == null) {
      out.print("Invalid input (genstamp absent)");
      return;
    }
    genStamp = Long.parseLong(blockGenStamp);

    String blockSizeStr;
    long blockSize = 0;
    blockSizeStr = req.getParameter("blockSize");
    if (blockSizeStr == null) {
      out.print("Invalid input (blockSize absent)");
      return;
    }
    blockSize = Long.parseLong(blockSizeStr);

    String chunkSizeToViewStr = req.getParameter("chunkSizeToView");
    if (chunkSizeToViewStr != null && Integer.parseInt(chunkSizeToViewStr) > 0)
      chunkSizeToView = Integer.parseInt(chunkSizeToViewStr);
    else chunkSizeToView = JspHelper.getDefaultChunkSize(conf);

    String startOffsetStr = req.getParameter("startOffset");
    if (startOffsetStr == null || Long.parseLong(startOffsetStr) < 0) startOffset = 0;
    else startOffset = Long.parseLong(startOffsetStr);

    String datanodePortStr = req.getParameter("datanodePort");
    if (datanodePortStr == null) {
      out.print("Invalid input (datanodePort absent)");
      return;
    }
    datanodePort = Integer.parseInt(datanodePortStr);
    out.print("<h3>File: ");
    JspHelper.printPathWithLinks(
        HtmlQuoting.quoteHtmlChars(filename), out, namenodeInfoPort, tokenString);
    out.print("</h3><hr>");
    String parent = new File(filename).getParent();
    JspHelper.printGotoForm(out, namenodeInfoPort, tokenString, HtmlQuoting.quoteHtmlChars(parent));
    out.print("<hr>");
    out.print(
        "<a href=\"http://"
            + req.getServerName()
            + ":"
            + req.getServerPort()
            + "/browseDirectory.jsp?dir="
            + URLEncoder.encode(parent, "UTF-8")
            + "&namenodeInfoPort="
            + namenodeInfoPort
            + "\"><i>Go back to dir listing</i></a><br>");
    out.print("<a href=\"#viewOptions\">Advanced view/download options</a><br>");
    out.print("<hr>");

    // Determine the prev & next blocks
    long nextStartOffset = 0;
    long nextBlockSize = 0;
    String nextBlockIdStr = null;
    String nextGenStamp = null;
    String nextHost = req.getServerName();
    int nextPort = req.getServerPort();
    int nextDatanodePort = datanodePort;
    // determine data for the next link
    if (startOffset + chunkSizeToView >= blockSize) {
      // we have to go to the next block from this point onwards
      List<LocatedBlock> blocks =
          dfs.namenode.getBlockLocations(filename, 0, Long.MAX_VALUE).getLocatedBlocks();
      for (int i = 0; i < blocks.size(); i++) {
        if (blocks.get(i).getBlock().getBlockId() == blockId) {
          if (i != blocks.size() - 1) {
            LocatedBlock nextBlock = blocks.get(i + 1);
            nextBlockIdStr = Long.toString(nextBlock.getBlock().getBlockId());
            nextGenStamp = Long.toString(nextBlock.getBlock().getGenerationStamp());
            nextStartOffset = 0;
            nextBlockSize = nextBlock.getBlock().getNumBytes();
            DatanodeInfo d = jspHelper.bestNode(nextBlock);
            String datanodeAddr = d.getName();
            nextDatanodePort =
                Integer.parseInt(
                    datanodeAddr.substring(datanodeAddr.indexOf(':') + 1, datanodeAddr.length()));
            nextHost = InetAddress.getByName(d.getHost()).getCanonicalHostName();
            nextPort = d.getInfoPort();
          }
        }
      }
    } else {
      // we are in the same block
      nextBlockIdStr = blockIdStr;
      nextStartOffset = startOffset + chunkSizeToView;
      nextBlockSize = blockSize;
      nextGenStamp = blockGenStamp;
    }
    String nextUrl = null;
    if (nextBlockIdStr != null) {
      nextUrl =
          "http://"
              + nextHost
              + ":"
              + nextPort
              + "/browseBlock.jsp?blockId="
              + nextBlockIdStr
              + "&blockSize="
              + nextBlockSize
              + "&startOffset="
              + nextStartOffset
              + "&genstamp="
              + nextGenStamp
              + "&filename="
              + URLEncoder.encode(filename, "UTF-8")
              + "&chunkSizeToView="
              + chunkSizeToView
              + "&datanodePort="
              + nextDatanodePort
              + "&namenodeInfoPort="
              + namenodeInfoPort
              + JspHelper.getDelegationTokenUrlParam(tokenString);
      out.print("<a href=\"" + nextUrl + "\">View Next chunk</a>&nbsp;&nbsp;");
    }
    // determine data for the prev link
    String prevBlockIdStr = null;
    String prevGenStamp = null;
    long prevStartOffset = 0;
    long prevBlockSize = 0;
    String prevHost = req.getServerName();
    int prevPort = req.getServerPort();
    int prevDatanodePort = datanodePort;
    if (startOffset == 0) {
      List<LocatedBlock> blocks =
          dfs.namenode.getBlockLocations(filename, 0, Long.MAX_VALUE).getLocatedBlocks();
      for (int i = 0; i < blocks.size(); i++) {
        if (blocks.get(i).getBlock().getBlockId() == blockId) {
          if (i != 0) {
            LocatedBlock prevBlock = blocks.get(i - 1);
            prevBlockIdStr = Long.toString(prevBlock.getBlock().getBlockId());
            prevGenStamp = Long.toString(prevBlock.getBlock().getGenerationStamp());
            prevStartOffset = prevBlock.getBlock().getNumBytes() - chunkSizeToView;
            if (prevStartOffset < 0) prevStartOffset = 0;
            prevBlockSize = prevBlock.getBlock().getNumBytes();
            DatanodeInfo d = jspHelper.bestNode(prevBlock);
            String datanodeAddr = d.getName();
            prevDatanodePort =
                Integer.parseInt(
                    datanodeAddr.substring(datanodeAddr.indexOf(':') + 1, datanodeAddr.length()));
            prevHost = InetAddress.getByName(d.getHost()).getCanonicalHostName();
            prevPort = d.getInfoPort();
          }
        }
      }
    } else {
      // we are in the same block
      prevBlockIdStr = blockIdStr;
      prevStartOffset = startOffset - chunkSizeToView;
      if (prevStartOffset < 0) prevStartOffset = 0;
      prevBlockSize = blockSize;
      prevGenStamp = blockGenStamp;
    }

    String prevUrl = null;
    if (prevBlockIdStr != null) {
      prevUrl =
          "http://"
              + prevHost
              + ":"
              + prevPort
              + "/browseBlock.jsp?blockId="
              + prevBlockIdStr
              + "&blockSize="
              + prevBlockSize
              + "&startOffset="
              + prevStartOffset
              + "&filename="
              + URLEncoder.encode(filename, "UTF-8")
              + "&chunkSizeToView="
              + chunkSizeToView
              + "&genstamp="
              + prevGenStamp
              + "&datanodePort="
              + prevDatanodePort
              + "&namenodeInfoPort="
              + namenodeInfoPort
              + JspHelper.getDelegationTokenUrlParam(tokenString);
      out.print("<a href=\"" + prevUrl + "\">View Prev chunk</a>&nbsp;&nbsp;");
    }
    out.print("<hr>");
    out.print("<textarea cols=\"100\" rows=\"25\" wrap=\"virtual\" style=\"width:100%\" READONLY>");
    try {
      jspHelper.streamBlockInAscii(
          new InetSocketAddress(req.getServerName(), datanodePort),
          blockId,
          accessToken,
          genStamp,
          blockSize,
          startOffset,
          chunkSizeToView,
          out,
          conf);
    } catch (Exception e) {
      out.print(e);
    }
    out.print("</textarea>");
    dfs.close();
  }