Class DynamicBloomFilter

  • All Implemented Interfaces:
    org.apache.hadoop.io.Writable

    public class DynamicBloomFilter
    extends Filter
    Implements a dynamic Bloom filter, as defined in the INFOCOM 2006 paper.

    A dynamic Bloom filter (DBF) makes use of a s * m bit matrix but each of the s rows is a standard Bloom filter. The creation process of a DBF is iterative. At the start, the DBF is a 1 * m bit matrix, i.e., it is composed of a single standard Bloom filter. It assumes that nr elements are recorded in the initial bit vector, where nr <= n (n is the cardinality of the set A to record in the filter).

    As the size of A grows during the execution of the application, several keys must be inserted in the DBF. When inserting a key into the DBF, one must first get an active Bloom filter in the matrix. A Bloom filter is active when the number of recorded keys, nr, is strictly less than the current cardinality of A, n. If an active Bloom filter is found, the key is inserted and nr is incremented by one. On the other hand, if there is no active Bloom filter, a new one is created (i.e., a new row is added to the matrix) according to the current size of A and the element is added in this new Bloom filter and the nr value of this new Bloom filter is set to one. A given key is said to belong to the DBF if the k positions are set to one in one of the matrix rows.

    Originally created by European Commission One-Lab Project 034819.

    See Also:
    The general behavior of a filter, A Bloom filter, Theory and Network Applications of Dynamic Bloom Filters
    • Constructor Detail

      • DynamicBloomFilter

        public DynamicBloomFilter()
        Zero-args constructor for the serialization.
      • DynamicBloomFilter

        public DynamicBloomFilter​(int vectorSize,
                                  int nbHash,
                                  int hashType,
                                  int nr)
        Constructor.

        Builds an empty Dynamic Bloom filter.

        Parameters:
        vectorSize - The number of bits in the vector.
        nbHash - The number of hash function to consider.
        hashType - type of the hashing function (see Hash).
        nr - The threshold for the maximum number of keys to record in a dynamic Bloom filter row.
    • Method Detail

      • add

        public boolean add​(org.apache.hadoop.util.bloom.Key key)
        Description copied from class: Filter
        Adds a key to this filter.
        Specified by:
        add in class Filter
        Parameters:
        key - The key to add.
        Returns:
        true if the key was added, false otherwise.
      • and

        public void and​(Filter filter)
        Description copied from class: Filter
        Performs a logical AND between this filter and a specified filter.

        Invariant: The result is assigned to this filter.

        Specified by:
        and in class Filter
        Parameters:
        filter - The filter to AND with.
      • membershipTest

        public boolean membershipTest​(org.apache.hadoop.util.bloom.Key key)
        Description copied from class: Filter
        Determines whether a specified key belongs to this filter.
        Specified by:
        membershipTest in class Filter
        Parameters:
        key - The key to test.
        Returns:
        boolean True if the specified key belongs to this filter. False otherwise.
      • not

        public void not()
        Description copied from class: Filter
        Performs a logical NOT on this filter.

        The result is assigned to this filter.

        Specified by:
        not in class Filter
      • or

        public void or​(Filter filter)
        Description copied from class: Filter
        Performs a logical OR between this filter and a specified filter.

        Invariant: The result is assigned to this filter.

        Specified by:
        or in class Filter
        Parameters:
        filter - The filter to OR with.
      • xor

        public void xor​(Filter filter)
        Description copied from class: Filter
        Performs a logical XOR between this filter and a specified filter.

        Invariant: The result is assigned to this filter.

        Specified by:
        xor in class Filter
        Parameters:
        filter - The filter to XOR with.