Package com.helger.base.hashcode

Class HashCodeCalculator

java.lang.Object

com.helger.base.hashcode.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	Description
static final int	HASHCODE_NULL	The hash code value to be used for null values.
static final int	INITIAL_HASHCODE	Use a prime number as the start.
static final int	MULTIPLIER	Each value is multiplied with this value. 31 because it can easily be optimized to (1 << 5) - 1.

Method Summary

Modifier and Type	Method	Description
static int	append(int nPrevHashCode, boolean x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, boolean @Nullable [] x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, boolean @Nullable [] x, int nOfs, int nLen)	Atomic type hash code generation.
static int	append(int nPrevHashCode, byte x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, byte @Nullable [] x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, byte @Nullable [] x, int nOfs, int nLen)	Atomic type hash code generation.
static int	append(int nPrevHashCode, char x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, char @Nullable [] x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, char @Nullable [] x, int nOfs, int nLen)	Atomic type hash code generation.
static int	append(int nPrevHashCode, double x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, double @Nullable [] x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, double @Nullable [] x, int nOfs, int nLen)	Atomic type hash code generation.
static int	append(int nPrevHashCode, float x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, float @Nullable [] x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, float @Nullable [] x, int nOfs, int nLen)	Atomic type hash code generation.
static int	append(int nPrevHashCode, int x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, int @Nullable [] x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, int @Nullable [] x, int nOfs, int nLen)	Atomic type hash code generation.
static int	append(int nPrevHashCode, long x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, long @Nullable [] x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, long @Nullable [] x, int nOfs, int nLen)	Atomic type hash code generation.
static int	append(int nPrevHashCode, short x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, short @Nullable [] x)	Atomic type hash code generation.
static int	append(int nPrevHashCode, short @Nullable [] x, int nOfs, int nLen)	Atomic type hash code generation.
static int	append(int nPrevHashCode, @Nullable Object x)	Object hash code generation.
static int	append(int nPrevHashCode, @Nullable Object[] x)	Array hash code generation.
static int	append(int nPrevHashCode, @Nullable Object[] x, int nOfs, int nLen)	Atomic type hash code generation.
static int	hashCode(boolean x)
static int	hashCode(boolean @NonNull [] x, int nOfs, int nLen)	Compute a hash code for a sub-array of booleans.
static int	hashCode(byte x)
static int	hashCode(byte @NonNull [] x, int nOfs, int nLen)	Compute a hash code for a sub-array of bytes.
static int	hashCode(char x)
static int	hashCode(char @NonNull [] x, int nOfs, int nLen)	Compute a hash code for a sub-array of chars.
static long	hashCode(double x)
static int	hashCode(double @NonNull [] x, int nOfs, int nLen)	Compute a hash code for a sub-array of doubles.
static int	hashCode(float x)
static int	hashCode(float @NonNull [] x, int nOfs, int nLen)	Compute a hash code for a sub-array of floats.
static int	hashCode(int @NonNull [] x, int nOfs, int nLen)	Compute a hash code for a sub-array of ints.
static int	hashCode(long @NonNull [] x, int nOfs, int nLen)	Compute a hash code for a sub-array of longs.
static int	hashCode(short x)
static int	hashCode(short @NonNull [] x, int nOfs, int nLen)	Compute a hash code for a sub-array of shorts.
static int	hashCode(@NonNull Object[] x, int nOfs, int nLen)	Compute a hash code for a sub-array of objects.
static int	hashCode(@Nullable Object x)

Methods inherited from class java.lang.Object

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

Field Details

INITIAL_HASHCODE

public static final int INITIAL_HASHCODE

Use a prime number as the start.

See Also:

• Constant Field Values

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 Details

hashCode

public static int hashCode(boolean x)

Parameters:

x - The value to hash.

Returns:

The hash code for the boolean value.

hashCode

public static int hashCode(byte x)

Parameters:

x - The value to hash.

Returns:

The hash code for the byte value.

hashCode

public static int hashCode(char x)

Parameters:

x - The value to hash.

Returns:

The hash code for the char value.

hashCode

public static long hashCode(double x)

Parameters:

x - The value to hash.

Returns:

The hash code for the double value.

hashCode

public static int hashCode(float x)

Parameters:

x - The value to hash.

Returns:

The hash code for the float value.

hashCode

public static int hashCode(short x)

Parameters:

x - The value to hash.

Returns:

The hash code for the short value.

hashCode

@UsedInGeneratedCode
public static int hashCode(@Nullable Object x)

Parameters:

x - The object to hash. May be null.

Returns:

The hash code for the object, or HASHCODE_NULL if null.

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

hashCode

public static int hashCode(boolean @NonNull [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Compute a hash code for a sub-array of booleans.

Parameters:

x - The array. May not be null.

nOfs - The offset. Must be ≥ 0.

nLen - The length. Must be ≥ 0.

Returns:

The computed hash code.

hashCode

public static int hashCode(byte @NonNull [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Compute a hash code for a sub-array of bytes.

Parameters:

x - The array. May not be null.

nOfs - The offset. Must be ≥ 0.

nLen - The length. Must be ≥ 0.

Returns:

The computed hash code.

hashCode

public static int hashCode(char @NonNull [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Compute a hash code for a sub-array of chars.

Parameters:

x - The array. May not be null.

nOfs - The offset. Must be ≥ 0.

nLen - The length. Must be ≥ 0.

Returns:

The computed hash code.

hashCode

public static int hashCode(double @NonNull [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Compute a hash code for a sub-array of doubles.

Parameters:

x - The array. May not be null.

nOfs - The offset. Must be ≥ 0.

nLen - The length. Must be ≥ 0.

Returns:

The computed hash code.

hashCode

public static int hashCode(float @NonNull [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Compute a hash code for a sub-array of floats.

Parameters:

x - The array. May not be null.

nOfs - The offset. Must be ≥ 0.

nLen - The length. Must be ≥ 0.

Returns:

The computed hash code.

hashCode

public static int hashCode(int @NonNull [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Compute a hash code for a sub-array of ints.

Parameters:

x - The array. May not be null.

nOfs - The offset. Must be ≥ 0.

nLen - The length. Must be ≥ 0.

Returns:

The computed hash code.

hashCode

public static int hashCode(long @NonNull [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Compute a hash code for a sub-array of longs.

Parameters:

x - The array. May not be null.

nOfs - The offset. Must be ≥ 0.

nLen - The length. Must be ≥ 0.

Returns:

The computed hash code.

hashCode

public static int hashCode(short @NonNull [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Compute a hash code for a sub-array of shorts.

Parameters:

x - The array. May not be null.

nOfs - The offset. Must be ≥ 0.

nLen - The length. Must be ≥ 0.

Returns:

The computed hash code.

hashCode

public static int hashCode(@NonNull Object[] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Compute a hash code for a sub-array of objects.

Parameters:

x - The array. May not be null.

nOfs - The offset. Must be ≥ 0.

nLen - The length. Must be ≥ 0.

Returns:

The computed hash code.

append

public static int append(int nPrevHashCode,
 boolean @Nullable [] 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,
 boolean @Nullable [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Atomic type hash code generation.

Parameters:

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

x - Array to add

nOfs - Offset to start from. Must be ≥ 0.

nLen - Number of array items to use. Must be ≥ 0.

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
 byte @Nullable [] 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 @Nullable [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Atomic type hash code generation.

Parameters:

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

x - Array to add

nOfs - Offset to start from. Must be ≥ 0.

nLen - Number of array items to use. Must be ≥ 0.

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
 char @Nullable [] 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 @Nullable [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Atomic type hash code generation.

Parameters:

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

x - Array to add

nOfs - Offset to start from. Must be ≥ 0.

nLen - Number of array items to use. Must be ≥ 0.

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
 double @Nullable [] 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 @Nullable [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Atomic type hash code generation.

Parameters:

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

x - Array to add

nOfs - Offset to start from. Must be ≥ 0.

nLen - Number of array items to use. Must be ≥ 0.

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
 float @Nullable [] 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 @Nullable [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Atomic type hash code generation.

Parameters:

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

x - Array to add

nOfs - Offset to start from. Must be ≥ 0.

nLen - Number of array items to use. Must be ≥ 0.

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
 int @Nullable [] 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 @Nullable [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Atomic type hash code generation.

Parameters:

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

x - Array to add

nOfs - Offset to start from. Must be ≥ 0.

nLen - Number of array items to use. Must be ≥ 0.

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
 long @Nullable [] 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 @Nullable [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Atomic type hash code generation.

Parameters:

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

x - Array to add

nOfs - Offset to start from. Must be ≥ 0.

nLen - Number of array items to use. Must be ≥ 0.

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
 short @Nullable [] 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 @Nullable [] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Atomic type hash code generation.

Parameters:

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

x - Array to add

nOfs - Offset to start from. Must be ≥ 0.

nLen - Number of array items to use. Must be ≥ 0.

Returns:

The updated hash code

append

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

Array hash code generation.

Parameters:

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

x - Object array to add. May be null.

Returns:

The updated hash code

append

public static int append(int nPrevHashCode,
 @Nullable Object[] x,
 @Nonnegative
 int nOfs,
 @Nonnegative
 int nLen)

Atomic type hash code generation.

Parameters:

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

x - Array to add

nOfs - Offset to start from. Must be ≥ 0.

nLen - Number of array items to use. Must be ≥ 0.

Returns:

The updated hash code