com.google.common.hash

Class HashCode

java.lang.Object

com.google.common.hash.HashCode

@Beta
public abstract class HashCode
extends Object

An immutable hash code of arbitrary bit length.

Since:

11.0

Author:

Dimitris Andreou

Method Summary

Methods

Modifier and Type	Method and Description
abstract byte[]	asBytes() Returns the value of this hash code as a byte array.
abstract int	asInt() Returns the first four bytes of this hashcode's bytes, converted to an int value in little-endian order.
abstract long	asLong() Returns the first eight bytes of this hashcode's bytes, converted to a long value in little-endian order.
abstract int	bits() Returns the number of bits in this hash code; a positive multiple of 8.
boolean	equals(Object object)
int	hashCode() Returns a "Java hash code" for this HashCode instance; this is well-defined (so, for example, you can safely put HashCode instances into a HashSet) but is otherwise probably not what you want to use.
abstract long	padToLong() If this hashcode has enough bits, returns asLong(), otherwise returns a long value with asInt() as the least-significant four bytes and 0x00 as each of the most-significant four bytes.
String	toString() Returns a string containing each byte of asBytes(), in order, as a two-digit unsigned hexadecimal number in lower case.
int	writeBytesTo(byte[] dest, int offset, int maxLength) Copies bytes from this hash code into dest.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

asInt

public abstract int asInt()

Returns the first four bytes of this hashcode's bytes, converted to an int value in little-endian order.

Throws:

IllegalStateException - if bits() < 32

asLong

public abstract long asLong()

Returns the first eight bytes of this hashcode's bytes, converted to a long value in little-endian order.

Throws:

IllegalStateException - if bits() < 64

padToLong

public abstract long padToLong()

If this hashcode has enough bits, returns asLong(), otherwise returns a long value with asInt() as the least-significant four bytes and 0x00 as each of the most-significant four bytes.

Since:

14.0 (since 11.0 as Hashing.padToLong(HashCode))

asBytes

public abstract byte[] asBytes()

Returns the value of this hash code as a byte array. The caller may modify the byte array; changes to it will not be reflected in this HashCode object or any other arrays returned by this method.

writeBytesTo

public int writeBytesTo(byte[] dest,
               int offset,
               int maxLength)

Copies bytes from this hash code into dest.

Parameters:

dest - the byte array into which the hash code will be written

offset - the start offset in the data

maxLength - the maximum number of bytes to write

Returns:

the number of bytes written to dest

Throws:

IndexOutOfBoundsException - if there is not enough room in dest

bits

public abstract int bits()

Returns the number of bits in this hash code; a positive multiple of 8.

equals

public boolean equals(@Nullable
             Object object)

Overrides:

equals in class Object

hashCode

public int hashCode()

Returns a "Java hash code" for this HashCode instance; this is well-defined (so, for example, you can safely put HashCode instances into a HashSet) but is otherwise probably not what you want to use.

Overrides:

hashCode in class Object

toString

public String toString()

Returns a string containing each byte of asBytes(), in order, as a two-digit unsigned hexadecimal number in lower case.

Note that if the output is considered to be a single hexadecimal number, this hash code's bytes are the big-endian representation of that number. This may be surprising since everything else in the hashing API uniformly treats multibyte values as little-endian. But this format conveniently matches that of utilities such as the UNIX md5sum command.

Overrides:

toString in class Object