Package org.tribuo.hash

Class Hasher

java.lang.Object

org.tribuo.hash.Hasher

All Implemented Interfaces:

com.oracle.labs.mlrg.olcut.config.Configurable, com.oracle.labs.mlrg.olcut.provenance.Provenancable<com.oracle.labs.mlrg.olcut.provenance.ConfiguredObjectProvenance>, Serializable, ProtoSerializable<org.tribuo.protos.core.HasherProto>

Direct Known Subclasses:

HashCodeHasher, MessageDigestHasher, ModHashCodeHasher

public abstract class Hasher
extends Object
implements com.oracle.labs.mlrg.olcut.config.Configurable, com.oracle.labs.mlrg.olcut.provenance.Provenancable<com.oracle.labs.mlrg.olcut.provenance.ConfiguredObjectProvenance>, Serializable, ProtoSerializable<org.tribuo.protos.core.HasherProto>

An abstract base class for hash functions used to hash the names of features.

Hasher implementations do not serialize the salt in their serialized forms, and thus the salt must be set after deserialization.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final int	MIN_LENGTH	The minimum length of the salt.

Fields inherited from interface org.tribuo.protos.ProtoSerializable

DESERIALIZATION_METHOD_NAME, PROVENANCE_SERIALIZER

Constructor Summary

Constructors

Constructor	Description
Hasher()

Method Summary

Modifier and Type	Method	Description
abstract String	hash(String input)	Hashes the supplied input using the hashing function.
abstract void	setSalt(String salt)	The salt is transient, it must be set **to the same value as it was trained with** after the Model is deserialized.
static boolean	validateSalt(String salt)	Salt validation is currently a test to see if the string is longer than MIN_LENGTH.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.oracle.labs.mlrg.olcut.config.Configurable

postConfig

Methods inherited from interface org.tribuo.protos.ProtoSerializable

serialize

Methods inherited from interface com.oracle.labs.mlrg.olcut.provenance.Provenancable

getProvenance

Field Details

MIN_LENGTH

public static final int MIN_LENGTH

The minimum length of the salt. Salts shorter than this will not validate.

See Also:

• Constant Field Values

Constructor Details

Hasher

public Hasher()

Method Details

hash

public abstract String hash(String input)

Hashes the supplied input using the hashing function.

If the salt is not set then this throws IllegalStateException.

Parameters:

input - The input to hash.

Returns:

A String representation of the hashed output.

setSalt

public abstract void setSalt(String salt)

The salt is transient, it must be set **to the same value as it was trained with** after the Model is deserialized.

Parameters:

salt - Salt value.

validateSalt

public static boolean validateSalt(String salt)

Salt validation is currently a test to see if the string is longer than MIN_LENGTH.

When this method is updated Hasher must update it's serialVersionUID, this ensures that serialised instances of downstream classes which call this method are invalidated, as changes to validateSalt may invalidate old salts, and there is no other way to communicate this to the developer.

Parameters:

salt - String to validate.

Returns:

True if the salt is valid, false otherwise.