net.named_data.jndn.sync.detail

Class InvertibleBloomLookupTable

java.lang.Object

net.named_data.jndn.sync.detail.InvertibleBloomLookupTable

public class InvertibleBloomLookupTable
extends Object

InvertibleBloomLookupTable implements an Invertible Bloom Lookup Table (IBLT) (Invertible Bloom Filter). This is used by FullPSync2017.

Field Summary

Fields

Modifier and Type	Field and Description
static int	N_HASH
static int	N_HASHCHECK

Constructor Summary

Constructors

Constructor and Description
InvertibleBloomLookupTable(int expectedNEntries) Create an InvertibleBloomLookupTable.
InvertibleBloomLookupTable(InvertibleBloomLookupTable iblt) Create an InvertibleBloomLookupTable of the given iblt.

Method Summary

Modifier and Type	Method and Description
InvertibleBloomLookupTable	difference(InvertibleBloomLookupTable other) Get a new IBLT which is the difference of the other IBLT from this IBLT.
Blob	encode() Encode this IBLT to a Blob.
boolean	equals(InvertibleBloomLookupTable other) Check if this IBLT has the same number of entries as the other IBLT and that they are equal.
void	erase(long key)
void	initialize(Blob encoding) Populate the hash table using the encoded array representation of the IBLT.
void	insert(long key)
boolean	listEntries(HashSet<Long> positive, HashSet<Long> negative) List all the entries in the IBLT.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

N_HASH

public static final int N_HASH

See Also:

Constant Field Values

N_HASHCHECK

public static final int N_HASHCHECK

See Also:

Constant Field Values

Constructor Detail

InvertibleBloomLookupTable

public InvertibleBloomLookupTable(int expectedNEntries)

Create an InvertibleBloomLookupTable.

Parameters:

expectedNEntries - the expected number of entries in the IBLT.

InvertibleBloomLookupTable

public InvertibleBloomLookupTable(InvertibleBloomLookupTable iblt)

Create an InvertibleBloomLookupTable of the given iblt.

Parameters:

iblt - The InvertibleBloomLookupTable to copy.

Method Detail

initialize

public final void initialize(Blob encoding)
                      throws IOException

Populate the hash table using the encoded array representation of the IBLT.

Parameters:

encoding - The encoded representation of the IBLT.

Throws:

AssertionError - if the size of the decoded values is not compatible with this IBLT.

IOException

insert

public final void insert(long key)

erase

public final void erase(long key)

listEntries

public final boolean listEntries(HashSet<Long> positive,
                                 HashSet<Long> negative)

List all the entries in the IBLT. This is called on a difference of two IBLTs: ownIBLT - receivedIBLT. Entries listed in positive are in ownIBLT but not in receivedIBLT. Entries listed in negative are in receivedIBLT but not in ownIBLT.

Parameters:

positive - Add positive entries to this set. This first clears the set.

negative - Add negative entries to this set. This first clears the set.

Returns:

True if decoding is completed successfully.

difference

public final InvertibleBloomLookupTable difference(InvertibleBloomLookupTable other)

Get a new IBLT which is the difference of the other IBLT from this IBLT.

Parameters:

other - The other IBLT.

Returns:

A new IBLT of this - other.

encode

public final Blob encode()
                  throws IOException

Encode this IBLT to a Blob. This encodes this hash table from a uint32_t array to a uint8_t array. We create a uin8_t array 12 times the size of the uint32_t array. We put the first count in the first 4 cells, keySum in the next 4, and keyCheck in the next 4. We repeat for all the other cells of the hash table. Then we append this uint8_t array to the name.

Returns:

The encoded Blob.

Throws:

IOException

equals

public final boolean equals(InvertibleBloomLookupTable other)

Check if this IBLT has the same number of entries as the other IBLT and that they are equal.

Parameters:

other - The other OBLT to check.

Returns:

true if this IBLT is equal to the other, otherwise false.