org.grouplens.lenskit.util.io

Class Descriptions

java.lang.Object

org.grouplens.lenskit.util.io.Descriptions

public final class Descriptions
extends Object

Utility classes for AbstractDescriptionWriters.

Since:

2.1

Method Summary

Modifier and Type	Method and Description
static Describer<Object>	defaultDescriber() Get a default describer.
static HashDescriptionWriter	hashWriter(HashFunction func) Create a description writer for a particular hash function.
static HashDescriptionWriter	sha1Writer() Create a description writer that will compute a SHA1 hash.
static StringDescriptionWriter	stringWriter() Construct a new description writer that outputs a string.

Methods inherited from class java.lang.Object

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

Method Detail

sha1Writer

public static HashDescriptionWriter sha1Writer()

Create a description writer that will compute a SHA1 hash.

Returns:

A description writer computing a SHA1 hash.

hashWriter

public static HashDescriptionWriter hashWriter(HashFunction func)

Create a description writer for a particular hash function.

Parameters:

func - The hash function.

Returns:

A description writer that computes a hash using func.

stringWriter

public static StringDescriptionWriter stringWriter()

Construct a new description writer that outputs a string.

Returns:

A string description writer.

defaultDescriber

public static Describer<Object> defaultDescriber()

Get a default describer. This describer uses the following algorithm:

1. If the object is Describable, call its its Describable.describeTo(DescriptionWriter) method.
2. If the object is Serializable, write its class and a SHA1 checksum of its serialized form to the description.
3. Otherwise, generate a random UUID as the object’s description. This UUID is remembered, so the same object will have the same UUID within a single instance of the JVM.

Returns:

A describer implementing the logic above.