Java LobFile.Reader方法代码示例

import com.cloudera.sqoop.io.LobFile; //导入方法依赖的package包/类
/**
 * Open a LobFile for read access, returning a cached reader if one is
 * available, or a new reader otherwise.
 * @param path the path to the LobFile to open
 * @param conf the configuration to use to access the FS.
 * @throws IOException if there's an error opening the file.
 */
public LobFile.Reader get(Path path, Configuration conf)
    throws IOException {

  LobFile.Reader reader = null;
  Path canonicalPath = qualify(path, conf);
  // Look up an entry in the cache.
  synchronized(this) {
    reader = readerMap.remove(canonicalPath);
  }

  if (null != reader && !reader.isClosed()) {
    // Cache hit. return it.
    LOG.debug("Using cached reader for " + canonicalPath);
    return reader;
  }

  // Cache miss; open the file.
  LOG.debug("No cached reader available for " + canonicalPath);
  return LobFile.open(path, conf);
}
 

import com.cloudera.sqoop.io.LobFile; //导入方法依赖的package包/类
/**
 * Return a reader back to the cache. If there's already a reader for
 * this path, then the current reader is closed.
 * @param reader the opened reader. Any record-specific subreaders should be
 * closed.
 * @throws IOException if there's an error accessing the path's filesystem.
 */
public void recycle(LobFile.Reader reader) throws IOException {
  Path canonicalPath = reader.getPath();

  // Check if the cache has a reader for this path already. If not, add this.
  boolean cached = false;
  synchronized(this) {
    if (readerMap.get(canonicalPath) == null) {
      LOG.debug("Caching reader for path: " + canonicalPath);
      readerMap.put(canonicalPath, reader);
      cached = true;
    }
  }

  if (!cached) {
    LOG.debug("Reader already present for path: " + canonicalPath
        + "; closing.");
    reader.close();
  }
}
 

import com.cloudera.sqoop.io.LobFile; //导入方法依赖的package包/类
@Override
protected synchronized void finalize() throws Throwable {
  for (LobFile.Reader r : readerMap.values()) {
    r.close();
  }

  super.finalize();
}
 

import com.cloudera.sqoop.io.LobFile; //导入方法依赖的package包/类
@Override
protected Reader getExternalSource(LobFile.Reader reader)
    throws IOException {
  return reader.readClobRecord();
}
 

import com.cloudera.sqoop.io.LobFile; //导入方法依赖的package包/类
@Override
protected InputStream getExternalSource(LobFile.Reader reader)
    throws IOException {
  return reader.readBlobRecord();
}
 

import com.cloudera.sqoop.io.LobFile; //导入方法依赖的package包/类
protected LobReaderCache() {
  this.readerMap = new TreeMap<Path, LobFile.Reader>();
}
 

import com.cloudera.sqoop.io.LobFile; //导入方法依赖的package包/类
/**
 * Using the LobFile reader, get an accessor InputStream or Reader to the
 * underlying data.
 */
protected abstract ACCESSORTYPE getExternalSource(LobFile.Reader reader)
    throws IOException;