com.phloc.commons.hash

Class HashCodeCalculator

java.lang.Object

com.phloc.commons.hash.HashCodeCalculator

@Immutable
public final class HashCodeCalculator
extends Object

This class provides the hash code generation for different data types.

Author:

Philip Helger

Field Summary

Fields

Modifier and Type	Field and Description
static int	HASHCODE_NULL The hash code value to be used for null values.
static int	MULTIPLIER Each value is multiplied with this value. 31 because it can easily be optimized to (1 << 5) - 1.

Method Summary

Methods

Modifier and Type	Method and Description
static int	append(int nPrevHashCode, boolean x) Atomic type hash code generation.
static int	append(int nPrevHashCode, byte x) Atomic type hash code generation.
static int	append(int nPrevHashCode, char x) Atomic type hash code generation.
static int	append(int nPrevHashCode, double x) Atomic type hash code generation.
static int	append(int nPrevHashCode, float x) Atomic type hash code generation.
static int	append(int nPrevHashCode, int x) Atomic type hash code generation.
static int	append(int nPrevHashCode, long x) Atomic type hash code generation.
static int	append(int nPrevHashCode, Object x) Object hash code generation.
static int	append(int nPrevHashCode, short x) Atomic type hash code generation.

Methods inherited from class java.lang.Object

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

Field Detail

MULTIPLIER

public static final int MULTIPLIER

Each value is multiplied with this value. 31 because it can easily be optimized to (1 << 5) - 1.

See Also:

Constant Field Values

HASHCODE_NULL

public static final int HASHCODE_NULL

The hash code value to be used for null values. Do not use 0 as e.g. BigDecimal ("0") also results in a 0 hash code.

See Also:

Constant Field Values

Method Detail

append

public static int append(int nPrevHashCode,
         boolean x)

Atomic type hash code generation.

Parameters:

nPrevHashCode - The previous hash code used as the basis for calculation

x - Array to add

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
         byte x)

Atomic type hash code generation.

Parameters:

nPrevHashCode - The previous hash code used as the basis for calculation

x - Array to add

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
         char x)

Atomic type hash code generation.

Parameters:

nPrevHashCode - The previous hash code used as the basis for calculation

x - Array to add

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
         double x)

Atomic type hash code generation.

Parameters:

nPrevHashCode - The previous hash code used as the basis for calculation

x - Array to add

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
         float x)

Atomic type hash code generation.

Parameters:

nPrevHashCode - The previous hash code used as the basis for calculation

x - Array to add

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
         int x)

Atomic type hash code generation.

Parameters:

nPrevHashCode - The previous hash code used as the basis for calculation

x - Array to add

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
         long x)

Atomic type hash code generation.

Parameters:

nPrevHashCode - The previous hash code used as the basis for calculation

x - Array to add

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
         short x)

Atomic type hash code generation.

Parameters:

nPrevHashCode - The previous hash code used as the basis for calculation

x - Array to add

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
         @Nullable
         Object x)

Object hash code generation.

Parameters:

nPrevHashCode - The previous hash code used as the basis for calculation

x - Object to add. May be null.

Returns:

The updated hash code