@InterfaceAudience.Public
 @InterfaceStability.Stable
public class DynamicBloomFilter
extends org.apache.hadoop.util.bloom.Filter
 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.
The general behavior of a filter, 
A Bloom filter, 
Theory and Network Applications of Dynamic Bloom Filters| Constructor and Description | 
|---|
| DynamicBloomFilter()Zero-args constructor for the serialization. | 
| DynamicBloomFilter(int vectorSize,
                  int nbHash,
                  int hashType,
                  int nr)Constructor. | 
| Modifier and Type | Method and Description | 
|---|---|
| void | add(org.apache.hadoop.util.bloom.Key key)Adds a key to this filter. | 
| void | and(org.apache.hadoop.util.bloom.Filter filter)Peforms a logical AND between this filter and a specified filter. | 
| boolean | membershipTest(org.apache.hadoop.util.bloom.Key key)Determines wether a specified key belongs to this filter. | 
| void | not()Performs a logical NOT on this filter. | 
| void | or(org.apache.hadoop.util.bloom.Filter filter)Peforms a logical OR between this filter and a specified filter. | 
| void | readFields(DataInput in)Deserialize the fields of this object from  in. | 
| String | toString() | 
| void | write(DataOutput out)Serialize the fields of this object to  out. | 
| void | xor(org.apache.hadoop.util.bloom.Filter filter)Peforms a logical XOR between this filter and a specified filter. | 
public DynamicBloomFilter()
public DynamicBloomFilter(int vectorSize,
                          int nbHash,
                          int hashType,
                          int nr)
Builds an empty Dynamic Bloom filter.
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.public void add(org.apache.hadoop.util.bloom.Key key)
org.apache.hadoop.util.bloom.Filteradd in class org.apache.hadoop.util.bloom.Filterkey - The key to add.public void and(org.apache.hadoop.util.bloom.Filter filter)
org.apache.hadoop.util.bloom.FilterInvariant: The result is assigned to this filter.
and in class org.apache.hadoop.util.bloom.Filterfilter - The filter to AND with.public boolean membershipTest(org.apache.hadoop.util.bloom.Key key)
org.apache.hadoop.util.bloom.FiltermembershipTest in class org.apache.hadoop.util.bloom.Filterkey - The key to test.public void not()
org.apache.hadoop.util.bloom.FilterThe result is assigned to this filter.
not in class org.apache.hadoop.util.bloom.Filterpublic void or(org.apache.hadoop.util.bloom.Filter filter)
org.apache.hadoop.util.bloom.FilterInvariant: The result is assigned to this filter.
or in class org.apache.hadoop.util.bloom.Filterfilter - The filter to OR with.public void xor(org.apache.hadoop.util.bloom.Filter filter)
org.apache.hadoop.util.bloom.FilterInvariant: The result is assigned to this filter.
xor in class org.apache.hadoop.util.bloom.Filterfilter - The filter to XOR with.public void write(DataOutput out) throws IOException
Writableout.write in interface Writablewrite in class org.apache.hadoop.util.bloom.Filterout - DataOuput to serialize this object into.IOException - any other problem for write.public void readFields(DataInput in) throws IOException
Writablein.  
 
 For efficiency, implementations should attempt to re-use storage in the existing object where possible.
readFields in interface WritablereadFields in class org.apache.hadoop.util.bloom.Filterin - DataInput to deseriablize this object from.IOException - any other problem for readFields.Copyright © 2023 Apache Software Foundation. All rights reserved.