org.jcoderz.commons.util
Class HashCodeUtil

  org.jcoderz.commons.util.HashCodeUtil

public final class HashCodeUtil
extends 

Collected methods which allow easy implementation of hashCode. Example use case:

 public int hashCode ()
 {
    int result = HashCodeUtil.SEED;
    //collect the contributions of various fields
    result = HashCodeUtil.hash(result, mPrimitive);
    result = HashCodeUtil.hash(result, mObject);
    result = HashCodeUtil.hash(result, mArray);
    return result;
 }
 

Author:

Michael Griffel

Field Summary

static int

SEED An initial value for a hashCode, to which is added contributions from fields.

Method Summary

static int	hash(int aSeed, boolean aBoolean) Constructs a new seed using the given Boolean and the previous seed.
static int	hash(int aSeed, char aChar) Constructs a new seed using the given boolean and the previous seed.
static int	hash(int aSeed, double aDouble) Constructs a new seed using the given double and the previous seed.
static int	hash(int aSeed, float aFloat) Constructs a new seed using the given float and the previous seed.
static int	hash(int aSeed, int aInt) Constructs a new seed using the given integer and the previous seed.
static int	hash(int aSeed, long aLong) Constructs a new seed using the given long and the previous seed.
static int	hash(int aSeed, aObject) Constructs a new seed using the given object and the previous seed.

Methods inherited from class java.lang.

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Field Detail

SEED

public static final int SEED

An initial value for a hashCode, to which is added contributions from fields. Using a non-zero value decreases collisons of hashCode values.

See Also:

Constant Field Values

Method Detail

hash

public static int hash(int aSeed,
                       boolean aBoolean)

Constructs a new seed using the given Boolean and the previous seed.

Parameters:

aSeed - the previous seed value.

aBoolean - the Boolean that should be added to the new seed.

Returns:

the new seed.

hash

public static int hash(int aSeed,
                       char aChar)

Constructs a new seed using the given boolean and the previous seed.

Parameters:

aSeed - the previous seed value.

aChar - the character that should be added to the new seed.

Returns:

the new seed.

hash

public static int hash(int aSeed,
                       int aInt)

Constructs a new seed using the given integer and the previous seed. Note that byte and short are handled by this method, through implicit conversion.

Parameters:

aSeed - the previous seed value.

aInt - the integer that should be added to the new seed.

Returns:

the new seed.

hash

public static int hash(int aSeed,
                       long aLong)

Constructs a new seed using the given long and the previous seed.

Parameters:

aSeed - the previous seed value.

aLong - the long value that should be added to the new seed.

Returns:

the new seed.

hash

public static int hash(int aSeed,
                       float aFloat)

Constructs a new seed using the given float and the previous seed.

Parameters:

aSeed - the previous seed value.

aFloat - the float that should be added to the new seed.

Returns:

the new seed.

hash

public static int hash(int aSeed,
                       double aDouble)

Constructs a new seed using the given double and the previous seed.

Parameters:

aSeed - the previous seed value.

aDouble - the double that should be added to the new seed.

Returns:

the new seed.

hash

public static int hash(int aSeed,
                        aObject)

Constructs a new seed using the given object and the previous seed. aObject is a possibly-null object field, and possibly an array. If aObject is an array, then each element may be a primitive or a possibly-null object.

Parameters:

aSeed - the previous seed value.

aObject - the integer that should be added to the new seed.

Returns:

the new seed.