Ejemplo n.º 1
0
 /**
  * Reads a byte stream, which was written by {@linkplain #writeTo(OutputStream)}, into a {@code
  * BloomFilter<T>}.
  *
  * <p>The {@code Funnel} to be used is not encoded in the stream, so it must be provided here.
  * <b>Warning:</b> the funnel provided <b>must</b> behave identically to the one used to populate
  * the original Bloom filter!
  *
  * @throws IOException if the InputStream throws an {@code IOException}, or if its data does not
  *     appear to be a BloomFilter serialized using the {@linkplain #writeTo(OutputStream)} method.
  */
 public static <T> BloomFilter<T> readFrom(InputStream in, Funnel<T> funnel) throws IOException {
   checkNotNull(in, "InputStream");
   checkNotNull(funnel, "Funnel");
   int strategyOrdinal = -1;
   int numHashFunctions = -1;
   int dataLength = -1;
   try {
     DataInputStream din = new DataInputStream(in);
     // currently this assumes there is no negative ordinal; will have to be updated if we
     // add non-stateless strategies (for which we've reserved negative ordinals; see
     // Strategy.ordinal()).
     strategyOrdinal = din.readByte();
     numHashFunctions = UnsignedBytes.toInt(din.readByte());
     dataLength = din.readInt();
     Strategy strategy = BloomFilterStrategies.values()[strategyOrdinal];
     long[] data = new long[dataLength];
     for (int i = 0; i < data.length; i++) {
       data[i] = din.readLong();
     }
     return new BloomFilter<T>(new BitArray(data), numHashFunctions, funnel, strategy);
   } catch (RuntimeException e) {
     IOException ioException =
         new IOException(
             "Unable to deserialize BloomFilter from InputStream."
                 + " strategyOrdinal: "
                 + strategyOrdinal
                 + " numHashFunctions: "
                 + numHashFunctions
                 + " dataLength: "
                 + dataLength);
     ioException.initCause(e);
     throw ioException;
   }
 }
Ejemplo n.º 2
0
 /**
  * This test will fail whenever someone updates/reorders the BloomFilterStrategies constants. Only
  * appending a new constant is allowed.
  */
 public void testBloomFilterStrategies() {
   assertThat(BloomFilterStrategies.values()).hasLength(2);
   assertEquals(BloomFilterStrategies.MURMUR128_MITZ_32, BloomFilterStrategies.values()[0]);
   assertEquals(BloomFilterStrategies.MURMUR128_MITZ_64, BloomFilterStrategies.values()[1]);
 }