Java FSUtils.isExists方法代码示例

import org.apache.hadoop.hbase.util.FSUtils; //导入方法依赖的package包/类
/**
 * Write out an info file under the region directory. Useful recovering mangled regions.
 *
 * @param regionInfoContent serialized version of the {@link HRegionInfo}
 * @param useTempDir        indicate whether or not using the region .tmp dir for a safer file creation.
 */
private void writeRegionInfoOnFilesystem(final byte[] regionInfoContent, final boolean useTempDir)
    throws IOException {
  Path regionInfoFile = new Path(getRegionDir(), REGION_INFO_FILE);
  if (useTempDir) {
    // Create in tmpDir and then move into place in case we crash after
    // create but before close. If we don't successfully close the file,
    // subsequent region reopens will fail the below because create is
    // registered in NN.

    // And then create the file
    Path tmpPath = new Path(getTempDir(), REGION_INFO_FILE);

    // If datanode crashes or if the RS goes down just before the close is
    // called while trying to
    // close the created regioninfo file in the .tmp directory then on next
    // creation we will be getting AlreadyCreatedException.
    // Hence delete and create the file if exists.
    if (FSUtils.isExists(fs, tmpPath)) {
      FSUtils.delete(fs, tmpPath, true);
    }

    // Write HRI to a file in case we need to recover hbase:meta
    writeRegionInfoFileContent(conf, fs, tmpPath, regionInfoContent);

    // Move the created file to the original path
    if (fs.exists(tmpPath) && !rename(tmpPath, regionInfoFile)) {
      throw new IOException("Unable to rename " + tmpPath + " to " + regionInfoFile);
    }
  } else {
    // Write HRI to a file in case we need to recover hbase:meta
    writeRegionInfoFileContent(conf, fs, regionInfoFile, regionInfoContent);
  }
}
 

import org.apache.hadoop.hbase.util.FSUtils; //导入方法依赖的package包/类
/**
 * Checks if a daughter region -- either splitA or splitB -- still holds
 * references to parent.
 * @param parent Parent region
 * @param daughter Daughter region
 * @return A pair where the first boolean says whether or not the daughter
 * region directory exists in the filesystem and then the second boolean says
 * whether the daughter has references to the parent.
 * @throws IOException
 */
Pair<Boolean, Boolean> checkDaughterInFs(final HRegionInfo parent, final HRegionInfo daughter)
throws IOException {
  if (daughter == null)  {
    return new Pair<Boolean, Boolean>(Boolean.FALSE, Boolean.FALSE);
  }

  FileSystem fs = this.services.getMasterFileSystem().getFileSystem();
  Path rootdir = this.services.getMasterFileSystem().getRootDir();
  Path tabledir = FSUtils.getTableDir(rootdir, daughter.getTable());

  Path daughterRegionDir = new Path(tabledir, daughter.getEncodedName());

  HRegionFileSystem regionFs = null;

  try {
    if (!FSUtils.isExists(fs, daughterRegionDir)) {
      return new Pair<Boolean, Boolean>(Boolean.FALSE, Boolean.FALSE);
    }
  } catch (IOException ioe) {
    LOG.warn("Error trying to determine if daughter region exists, " +
             "assuming exists and has references", ioe);
    return new Pair<Boolean, Boolean>(Boolean.TRUE, Boolean.TRUE);
  }

  try {
    regionFs = HRegionFileSystem.openRegionFromFileSystem(
        this.services.getConfiguration(), fs, tabledir, daughter, true);
  } catch (IOException e) {
    LOG.warn("Error trying to determine referenced files from : " + daughter.getEncodedName()
        + ", to: " + parent.getEncodedName() + " assuming has references", e);
    return new Pair<Boolean, Boolean>(Boolean.TRUE, Boolean.TRUE);
  }

  boolean references = false;
  HTableDescriptor parentDescriptor = getTableDescriptor(parent.getTable());
  for (HColumnDescriptor family: parentDescriptor.getFamilies()) {
    if ((references = regionFs.hasReferences(family.getNameAsString()))) {
      break;
    }
  }
  return new Pair<Boolean, Boolean>(Boolean.TRUE, Boolean.valueOf(references));
}