com.mongodb.util
Class Hash

java.lang.Object
  com.mongodb.util.Hash

public final class Hash
extends Object

Constructor Summary

Hash()

Method Summary

static int	hashBackward(String s) Creates a hash for a string.
static long	hashBackwardLong(String s) Creates a long hash for a string.
static int	hashCode(CharSequence s, int start, int end) Creates a hash code of a string from [start-end)
static int	hashCode(String... strings) Calculate the hashcode for a series of strings combined as one.
static long	longHash(String s) 64-bit hash, using longs, in stead of ints, for less collisions, for when it matters.
static long	longHash(String s, int start, int end) 64-bit hash using longs, starting on index 'start' and including everything before 'end'.
static long	longHashAppend(long hash, char c) Adds a character to an existing hash code.
static long	longLowerHash(String s) Same as longHash(String), using only lower-case values of letters.
static long	longLowerHash(String s, int start, int end) Long (64-bit) hash, lower-cased, from [start-end)
static long	longLowerHash(String s, int start, int end, long hash) Long (64-bit) hash, lower-cased, from [start-end)
static long	longLowerHashAppend(long hash, char c) Adds the lower-case equivalent of a character to an existing hash code.
static int	lowerCaseHash(String s) This is an exact copy of the String hashCode() function, aside from the lowercasing.
static int	lowerCaseHash(String s, int start, int end) Creates a hash code of a lowercase string from [start-end)
static int	lowerCaseSpaceTrimHash(String s) This is an exact copy of the String hashCode() function, aside from the lowercasing.
static int	lowerCaseSpaceTrimHash(String s, int start, int end) Creates a hash code of a lowercase string from [start-end) ignoring whitespace
static int	nospaceLowerHash(String s, int start, int end) Creates a hash code of a lowercase string with whitespace removed from [start-end)

Methods inherited from class java.lang.Object

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

Constructor Detail

Hash

public Hash()

Method Detail

hashBackward

public static final int hashBackward(String s)

Creates a hash for a string.

Parameters:

s - String to hash

Returns:

the hash code

hashBackwardLong

public static final long hashBackwardLong(String s)

Creates a long hash for a string.

Parameters:

s - the string to hash

Returns:

the hash code

longHash

public static final long longHash(String s)

64-bit hash, using longs, in stead of ints, for less collisions, for when it matters. Calls longHash( s , 0 , s.length() )

Parameters:

s - The String to hash.

Returns:

the hash code

longHash

public static final long longHash(String s,
                                  int start,
                                  int end)

64-bit hash using longs, starting on index 'start' and including everything before 'end'.

Parameters:

s - The string to hash.

start - Where to start the hash.

end - Where to end the hash.

Returns:

the hash code

longLowerHash

public static final long longLowerHash(String s)

Same as longHash(String), using only lower-case values of letters. Calls longhash( s , 0 , s.length() ).

Parameters:

s - The string to Hash.

Returns:

the hash code

longLowerHash

public static final long longLowerHash(String s,
                                       int start,
                                       int end)

Long (64-bit) hash, lower-cased, from [start-end)

Parameters:

s - The string to hash.

start - where to start hashing.

end - Where to stop hashing.

Returns:

the hash code

longLowerHash

public static final long longLowerHash(String s,
                                       int start,
                                       int end,
                                       long hash)

Long (64-bit) hash, lower-cased, from [start-end)

Parameters:

s - The string to hash.

start - where to start hashing.

end - Where to stop hashing.

Returns:

the hash code

longLowerHashAppend

public static final long longLowerHashAppend(long hash,
                                             char c)

Adds the lower-case equivalent of a character to an existing hash code.

Parameters:

hash - the existing hash code

c - the character to add

Returns:

the hash code

longHashAppend

public static final long longHashAppend(long hash,
                                        char c)

Adds a character to an existing hash code.

Parameters:

hash - the existing hash code

c - the character to add

Returns:

the hash code

lowerCaseHash

public static final int lowerCaseHash(String s)

This is an exact copy of the String hashCode() function, aside from the lowercasing.

Parameters:

s - string to be hashed

Returns:

the hash code

lowerCaseHash

public static final int lowerCaseHash(String s,
                                      int start,
                                      int end)

Creates a hash code of a lowercase string from [start-end)

Parameters:

s - string to be hashed

start - the starting index

end - the ending index

Returns:

the hash code

hashCode

public static final int hashCode(CharSequence s,
                                 int start,
                                 int end)

Creates a hash code of a string from [start-end)

Parameters:

s - string to be hashed

start - the starting index

end - the ending index

Returns:

the hash code

nospaceLowerHash

public static final int nospaceLowerHash(String s,
                                         int start,
                                         int end)

Creates a hash code of a lowercase string with whitespace removed from [start-end)

Parameters:

s - string to be hashed

start - the starting index

end - the ending index

Returns:

the hash code

lowerCaseSpaceTrimHash

public static final int lowerCaseSpaceTrimHash(String s)

This is an exact copy of the String hashCode() function, aside from the lowercasing. No, it's not. It also ignores consecutive whitespace.

Parameters:

s - string to be hashed

Returns:

the hash code

lowerCaseSpaceTrimHash

public static final int lowerCaseSpaceTrimHash(String s,
                                               int start,
                                               int end)

Creates a hash code of a lowercase string from [start-end) ignoring whitespace

Parameters:

s - string to be hashed

start - the starting index

end - the ending index

Returns:

the hash code

hashCode

public static final int hashCode(String... strings)

Calculate the hashcode for a series of strings combined as one.

Parameters:

strings - Varargs array of Strings.

Returns:

A hashcode.