Java Reader.createScannerByKey方法代码示例

import org.apache.hadoop.io.file.tfile.TFile.Reader; //导入方法依赖的package包/类
private void readValueBeforeKey(int recordIndex)
    throws IOException {
  Reader reader =
      new Reader(fs.open(path), fs.getFileStatus(path).getLen(), conf);
  Scanner scanner =
      reader.createScannerByKey(composeSortedKey(KEY, recordIndex)
          .getBytes(), null);

  try {
    byte[] vbuf = new byte[BUF_SIZE];
    int vlen = scanner.entry().getValueLength();
    scanner.entry().getValue(vbuf);
    Assert.assertEquals(new String(vbuf, 0, vlen), VALUE + recordIndex);

    byte[] kbuf = new byte[BUF_SIZE];
    int klen = scanner.entry().getKeyLength();
    scanner.entry().getKey(kbuf);
    Assert.assertEquals(new String(kbuf, 0, klen), composeSortedKey(KEY,
        recordIndex));
  } finally {
    scanner.close();
    reader.close();
  }
}
 

import org.apache.hadoop.io.file.tfile.TFile.Reader; //导入方法依赖的package包/类
private void readValueWithoutKey(int recordIndex)
    throws IOException {
  Reader reader = new Reader(fs.open(path), fs.getFileStatus(path).getLen(), conf);

  Scanner scanner =
      reader.createScannerByKey(composeSortedKey(KEY, recordIndex)
          .getBytes(), null);

  byte[] vbuf1 = new byte[BUF_SIZE];
  int vlen1 = scanner.entry().getValueLength();
  scanner.entry().getValue(vbuf1);
  Assert.assertEquals(new String(vbuf1, 0, vlen1), VALUE + recordIndex);

  if (scanner.advance() && !scanner.atEnd()) {
    byte[] vbuf2 = new byte[BUF_SIZE];
    int vlen2 = scanner.entry().getValueLength();
    scanner.entry().getValue(vbuf2);
    Assert.assertEquals(new String(vbuf2, 0, vlen2), VALUE
        + (recordIndex + 1));
  }

  scanner.close();
  reader.close();
}
 

import org.apache.hadoop.io.file.tfile.TFile.Reader; //导入方法依赖的package包/类
@Test
public void testFailureScannerWithKeys() throws IOException {
  Reader reader =
      new Reader(fs.open(path), fs.getFileStatus(path).getLen(), conf);
  Assert.assertFalse(reader.isSorted());
  Assert.assertEquals((int) reader.getEntryCount(), 4);

  try {
    Scanner scanner =
        reader.createScannerByKey("aaa".getBytes(), "zzz".getBytes());
    Assert
        .fail("Failed to catch creating scanner with keys on unsorted file.");
  }
  catch (RuntimeException e) {
  }
  finally {
    reader.close();
  }
}
 

import org.apache.hadoop.io.file.tfile.TFile.Reader; //导入方法依赖的package包/类
public void testFailureScannerWithKeys() throws IOException {
  Reader reader =
      new Reader(fs.open(path), fs.getFileStatus(path).getLen(), conf);
  Assert.assertFalse(reader.isSorted());
  Assert.assertEquals((int) reader.getEntryCount(), 4);

  try {
    Scanner scanner =
        reader.createScannerByKey("aaa".getBytes(), "zzz".getBytes());
    Assert
        .fail("Failed to catch creating scanner with keys on unsorted file.");
  }
  catch (RuntimeException e) {
  }
  finally {
    reader.close();
  }
}
 

import org.apache.hadoop.io.file.tfile.TFile.Reader; //导入方法依赖的package包/类
private void readKeyWithoutValue(int recordIndex)
    throws IOException {
  Reader reader = new Reader(fs.open(path), fs.getFileStatus(path).getLen(), conf);
  Scanner scanner =
      reader.createScannerByKey(composeSortedKey(KEY, recordIndex)
          .getBytes(), null);

  try {
    // read the indexed key
    byte[] kbuf1 = new byte[BUF_SIZE];
    int klen1 = scanner.entry().getKeyLength();
    scanner.entry().getKey(kbuf1);
    Assert.assertEquals(new String(kbuf1, 0, klen1), composeSortedKey(KEY,
        recordIndex));

    if (scanner.advance() && !scanner.atEnd()) {
      // read the next key following the indexed
      byte[] kbuf2 = new byte[BUF_SIZE];
      int klen2 = scanner.entry().getKeyLength();
      scanner.entry().getKey(kbuf2);
      Assert.assertEquals(new String(kbuf2, 0, klen2), composeSortedKey(KEY,
          recordIndex + 1));
    }
  } finally {
    scanner.close();
    reader.close();
  }
}
 

import org.apache.hadoop.io.file.tfile.TFile.Reader; //导入方法依赖的package包/类
private void readKeyManyTimes(int recordIndex) throws IOException {
  Reader reader = new Reader(fs.open(path), fs.getFileStatus(path).getLen(), conf);

  Scanner scanner =
      reader.createScannerByKey(composeSortedKey(KEY, recordIndex)
          .getBytes(), null);

  // read the indexed key
  byte[] kbuf1 = new byte[BUF_SIZE];
  int klen1 = scanner.entry().getKeyLength();
  scanner.entry().getKey(kbuf1);
  Assert.assertEquals(new String(kbuf1, 0, klen1), composeSortedKey(KEY,
      recordIndex));

  klen1 = scanner.entry().getKeyLength();
  scanner.entry().getKey(kbuf1);
  Assert.assertEquals(new String(kbuf1, 0, klen1), composeSortedKey(KEY,
      recordIndex));

  klen1 = scanner.entry().getKeyLength();
  scanner.entry().getKey(kbuf1);
  Assert.assertEquals(new String(kbuf1, 0, klen1), composeSortedKey(KEY,
      recordIndex));

  scanner.close();
  reader.close();
}
 

import org.apache.hadoop.io.file.tfile.TFile.Reader; //导入方法依赖的package包/类
/**
 * test none codecs
 */
void basicWithSomeCodec(String codec) throws IOException {
  Path ncTFile = new Path(ROOT, "basic.tfile");
  FSDataOutputStream fout = createFSOutput(ncTFile);
  Writer writer = new Writer(fout, minBlockSize, codec, "memcmp", conf);
  writeRecords(writer);
  fout.close();
  FSDataInputStream fin = fs.open(ncTFile);
  Reader reader =
      new Reader(fs.open(ncTFile), fs.getFileStatus(ncTFile).getLen(), conf);

  Scanner scanner = reader.createScanner();
  readAllRecords(scanner);
  scanner.seekTo(getSomeKey(50));
  assertTrue("location lookup failed", scanner.seekTo(getSomeKey(50)));
  // read the key and see if it matches
  byte[] readKey = readKey(scanner);
  assertTrue("seeked key does not match", Arrays.equals(getSomeKey(50),
      readKey));

  scanner.seekTo(new byte[0]);
  byte[] val1 = readValue(scanner);
  scanner.seekTo(new byte[0]);
  byte[] val2 = readValue(scanner);
  assertTrue(Arrays.equals(val1, val2));
  
  // check for lowerBound
  scanner.lowerBound(getSomeKey(50));
  assertTrue("locaton lookup failed", scanner.currentLocation
      .compareTo(reader.end()) < 0);
  readKey = readKey(scanner);
  assertTrue("seeked key does not match", Arrays.equals(readKey,
      getSomeKey(50)));

  // check for upper bound
  scanner.upperBound(getSomeKey(50));
  assertTrue("location lookup failed", scanner.currentLocation
      .compareTo(reader.end()) < 0);
  readKey = readKey(scanner);
  assertTrue("seeked key does not match", Arrays.equals(readKey,
      getSomeKey(51)));

  scanner.close();
  // test for a range of scanner
  scanner = reader.createScannerByKey(getSomeKey(10), getSomeKey(60));
  readAndCheckbytes(scanner, 10, 50);
  assertFalse(scanner.advance());
  scanner.close();
  reader.close();
  fin.close();
  fs.delete(ncTFile, true);
}