Code:
import java.util.*;
import java.security.*;
import java.math.*;
import java.nio.*;
/* Class BloomFilter */
class BloomFilter
{
private byte[] set;
private int keySize, setSize, size;
private MessageDigest md;
/* Constructor */
public BloomFilter(int capacity, int k)
{
setSize = capacity;
set = new byte[setSize];
keySize = k;
size = 0;
try
{
md = MessageDigest.getInstance("MD5");
}
catch (NoSuchAlgorithmException e)
{
throw new IllegalArgumentException("Error : MD5 Hash not found");
}
}
/* Function to clear bloom set */
public void makeEmpty()
{
set = new byte[setSize];
size = 0;
try
{
md = MessageDigest.getInstance("MD5");
}
catch (NoSuchAlgorithmException e)
{
throw new IllegalArgumentException("Error : MD5 Hash not found");
}
}
/* Function to check is empty */
public boolean isEmpty()
{
return size == 0;
}
/* Function to get size of objects added */
public int getSize()
{
return size;
}
/* Function to get hash - MD5 */
private int getHash(int i)
{
md.reset();
byte[] bytes = ByteBuffer.allocate(4).putInt(i).array();
md.update(bytes, 0, bytes.length);
return Math.abs(new BigInteger(1, md.digest()).intValue()) % (set.length - 1);
}
/* Function to add an object */
public void add(Object obj)
{
int[] tmpset = getSetArray(obj);
for (int i : tmpset)
set[i] = 1;
size++;
}
/* Function to check is an object is present */
public boolean contains(Object obj)
{
int[] tmpset = getSetArray(obj);
for (int i : tmpset)
if (set[i] != 1)
return false;
return true;
}
/* Function to get set array for an object */
private int[] getSetArray(Object obj)
{
int[] tmpset = new int[keySize];
tmpset[0] = getHash(obj.hashCode());
for (int i = 1; i < keySize; i++)
tmpset[i] = (getHash(tmpset[i - 1]));
return tmpset;
}
}
/* Class BloomFilterTest */
public class BloomFilterTest
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
System.out.println("Bloom Filter Test\n");
System.out.println("Enter set capacity and key size");
BloomFilter bf = new BloomFilter(scan.nextInt() , scan.nextInt());
char ch;
/* Perform bloom filter operations */
do
{
System.out.println("\nBloomFilter Operations\n");
System.out.println("1. insert ");
System.out.println("2. contains");
System.out.println("3. check empty");
System.out.println("4. clear");
System.out.println("5. size");
int choice = scan.nextInt();
switch (choice)
{
case 1 :
System.out.println("Enter integer element to insert");
bf.add( new Integer(scan.nextInt()) );
break;
case 2 :
System.out.println("Enter integer element to search");
System.out.println("Search result : "+ bf.contains( new Integer(scan.nextInt()) ));
break;
case 3 :
System.out.println("Empty status = "+ bf.isEmpty());
break;
case 4 :
System.out.println("\nBloom set Cleared");
bf.makeEmpty();
break;
case 5 :
System.out.println("\nSize = "+ bf.getSize() );
break;
default :
System.out.println("Wrong Entry \n ");
break;
}
System.out.println("\nDo you want to continue (Type y or n) \n");
ch = scan.next().charAt(0);
} while (ch == 'Y'|| ch == 'y');
}
}
Output:
Bloom Filter Test
Enter set capacity and key size
1000 1000
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
1
Enter integer element to insert
57
Do you want to continue (Type y or n)
y
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
1
Enter integer element to insert
97
Do you want to continue (Type y or n)
y
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
1
Enter integer element to insert
91
Do you want to continue (Type y or n)
y
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
1
Enter integer element to insert
23
Do you want to continue (Type y or n)
y
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
1
Enter integer element to insert
67
Do you want to continue (Type y or n)
y
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
2
Enter integer element to search
67
Search result : true
Do you want to continue (Type y or n)
y
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
2
Enter integer element to search
25
Search result : false
Do you want to continue (Type y or n)
y
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
2
Enter integer element to search
33
Search result : false
Do you want to continue (Type y or n)
y
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
2
Enter integer element to search
97
Search result : true
Do you want to continue (Type y or n)
y
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
5
Size = 5
Do you want to continue (Type y or n)
y
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
4
Bloom set Cleared
Do you want to continue (Type y or n)
y
BloomFilter Operations
1. insert
2. contains
3. check empty
4. clear
5. size
3
Empty status = true
Do you want to continue (Type y or n)
n
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