squidpony.squidmath

Class HashCommon.EnumHasher

java.lang.Object

squidpony.squidmath.HashCommon.EnumHasher

All Implemented Interfaces:

java.io.Serializable, CrossHash.IHasher

Enclosing class:

HashCommon

public static class HashCommon.EnumHasher
extends java.lang.Object
implements CrossHash.IHasher

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
EnumHasher()

Method Summary

Modifier and Type	Method and Description
boolean	areEqual(java.lang.Object left, java.lang.Object right) Not all types you might want to use an IHasher on meaningfully implement .equals(), such as array types; in these situations the areEqual method helps quickly check for equality by potentially having special logic for the type this is meant to check.
int	hash(java.lang.Object data) If data is a type that this IHasher can specifically hash, this method should use that specific hash; in other situations, it should simply delegate to calling Object.hashCode() on data.

Methods inherited from class java.lang.Object

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

Constructor Detail

EnumHasher

public EnumHasher()

Method Detail

hash

public int hash(java.lang.Object data)

Description copied from interface: CrossHash.IHasher

If data is a type that this IHasher can specifically hash, this method should use that specific hash; in other situations, it should simply delegate to calling Object.hashCode() on data. The body of an implementation of this method can be very small; for an IHasher that is meant for byte arrays, the body could be: return (data instanceof byte[]) ? CrossHash.Lightning.hash((byte[]) data) : data.hashCode();

Specified by:

hash in interface CrossHash.IHasher

Parameters:

data - the Object to hash; this method should take any type but often has special behavior for one type

Returns:

a 32-bit int hash code of data

areEqual

public boolean areEqual(java.lang.Object left,
                        java.lang.Object right)

Description copied from interface: CrossHash.IHasher

Not all types you might want to use an IHasher on meaningfully implement .equals(), such as array types; in these situations the areEqual method helps quickly check for equality by potentially having special logic for the type this is meant to check. The body of implementations for this method can be fairly small; for byte arrays, it looks like: return left == right || ((left instanceof byte[] && right instanceof byte[]) ? Arrays.equals((byte[]) left, (byte[]) right) : Objects.equals(left, right)); , but for multidimensional arrays you should use the CrossHash.equalityHelper(Object[], Object[], IHasher) method with an IHasher for the inner arrays that are 1D or otherwise already-hash-able, as can be seen in the body of the implementation for 2D char arrays, where charHasher is an existing IHasher that handles 1D arrays: return left == right || ((left instanceof char[][] && right instanceof char[][]) ? equalityHelper((char[][]) left, (char[][]) right, charHasher) : Objects.equals(left, right));

Specified by:

areEqual in interface CrossHash.IHasher

Parameters:

left - allowed to be null; most implementations will have special behavior for one type

right - allowed to be null; most implementations will have special behavior for one type

Returns:

true if left is equal to right (preferably by value, but reference equality may sometimes be needed)