org.lenskit.basic

Class PrecomputedItemScorer

java.lang.Object

org.lenskit.basic.AbstractItemScorer

org.lenskit.basic.PrecomputedItemScorer

All Implemented Interfaces:

Serializable, ItemScorer

public class PrecomputedItemScorer
extends AbstractItemScorer
implements Serializable

An item scorer that stores a precomputed map of item scores.

Since:

3.0

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PrecomputedItemScorer.Builder Builder for mock item scorers.

Method Summary

Modifier and Type	Method and Description
static PrecomputedItemScorer	fromCSV(BufferedReader buf) Read predictions from a CSV file.
static PrecomputedItemScorer.Builder	newBuilder() Construct a new builder for precomputed item scorers.
Result	score(long user, long item) Score a single item.
ResultMap	scoreWithDetails(long user, Collection<Long> items) Score a collection of items and potentially return more details on the scores.

Methods inherited from class org.lenskit.basic.AbstractItemScorer

score

Methods inherited from class java.lang.Object

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

Method Detail

score

public Result score(long user,
                    long item)

Description copied from class: AbstractItemScorer

Score a single item.

This implementation delegates to ItemScorer.scoreWithDetails(long, Collection).

Specified by:

score in interface ItemScorer

Overrides:

score in class AbstractItemScorer

Parameters:

user - The user ID for whom to generate a score.

item - The item ID to score.

Returns:

The score, or null if no score can be generated.

scoreWithDetails

@Nonnull
public ResultMap scoreWithDetails(long user,
                                            @Nonnull
                                            Collection<Long> items)

Description copied from interface: ItemScorer

Score a collection of items and potentially return more details on the scores.

Specified by:

scoreWithDetails in interface ItemScorer

Parameters:

user - The user ID for whom to generate scores.

items - The item to score.

Returns:

The scores for the items. This result set may not contain all requested items. Implementations that support additional details will return a subclass of ResultMap that provides access to those details.

fromCSV

public static PrecomputedItemScorer fromCSV(@WillClose
                                            BufferedReader buf)

Read predictions from a CSV file.

Parameters:

buf - A CSV file reader.

Returns:

The item scorer.

newBuilder

public static PrecomputedItemScorer.Builder newBuilder()

Construct a new builder for precomputed item scorers. This is useful for building item scorers for mocks.

Returns:

A new builder for item scorers.