public BloomFilter readBloomFilter()

in parquet-hadoop/src/main/java/org/apache/parquet/hadoop/ParquetFileReader.java [1598:1678]
68 lines of code
13 McCabe index (conditional complexity)

  public BloomFilter readBloomFilter(ColumnChunkMetaData meta) throws IOException {
    long bloomFilterOffset = meta.getBloomFilterOffset();
    if (bloomFilterOffset < 0) {
      return null;
    }

    // Prepare to decrypt Bloom filter (for encrypted columns)
    BlockCipher.Decryptor bloomFilterDecryptor = null;
    byte[] bloomFilterHeaderAAD = null;
    byte[] bloomFilterBitsetAAD = null;
    if (null != fileDecryptor && !fileDecryptor.plaintextFile()) {
      InternalColumnDecryptionSetup columnDecryptionSetup = fileDecryptor.getColumnSetup(meta.getPath());
      if (columnDecryptionSetup.isEncrypted()) {
        bloomFilterDecryptor = columnDecryptionSetup.getMetaDataDecryptor();
        bloomFilterHeaderAAD = AesCipher.createModuleAAD(
            fileDecryptor.getFileAAD(),
            ModuleType.BloomFilterHeader,
            meta.getRowGroupOrdinal(),
            columnDecryptionSetup.getOrdinal(),
            -1);
        bloomFilterBitsetAAD = AesCipher.createModuleAAD(
            fileDecryptor.getFileAAD(),
            ModuleType.BloomFilterBitset,
            meta.getRowGroupOrdinal(),
            columnDecryptionSetup.getOrdinal(),
            -1);
      }
    }

    // Seek to Bloom filter offset.
    f.seek(bloomFilterOffset);

    // Read Bloom filter length.
    int bloomFilterLength = meta.getBloomFilterLength();

    // If it is set, read Bloom filter header and bitset together.
    // Otherwise, read Bloom filter header first and then bitset.
    InputStream in = f;
    if (bloomFilterLength > 0) {
      byte[] headerAndBitSet = new byte[bloomFilterLength];
      f.readFully(headerAndBitSet);
      in = new ByteArrayInputStream(headerAndBitSet);
    }

    BloomFilterHeader bloomFilterHeader;
    try {
      bloomFilterHeader = Util.readBloomFilterHeader(in, bloomFilterDecryptor, bloomFilterHeaderAAD);
    } catch (IOException e) {
      LOG.warn("read no bloom filter");
      return null;
    }

    int numBytes = bloomFilterHeader.getNumBytes();
    if (numBytes <= 0 || numBytes > BlockSplitBloomFilter.UPPER_BOUND_BYTES) {
      LOG.warn("the read bloom filter size is wrong, size is {}", bloomFilterHeader.getNumBytes());
      return null;
    }

    if (!bloomFilterHeader.getHash().isSetXXHASH()
        || !bloomFilterHeader.getAlgorithm().isSetBLOCK()
        || !bloomFilterHeader.getCompression().isSetUNCOMPRESSED()) {
      LOG.warn(
          "the read bloom filter is not supported yet,  algorithm = {}, hash = {}, compression = {}",
          bloomFilterHeader.getAlgorithm(),
          bloomFilterHeader.getHash(),
          bloomFilterHeader.getCompression());
      return null;
    }

    byte[] bitset;
    if (null == bloomFilterDecryptor) {
      bitset = new byte[numBytes];
      in.read(bitset);
    } else {
      bitset = bloomFilterDecryptor.decrypt(in, bloomFilterBitsetAAD);
      if (bitset.length != numBytes) {
        throw new ParquetCryptoRuntimeException("Wrong length of decrypted bloom filter bitset");
      }
    }
    return new BlockSplitBloomFilter(bitset);
  }