org.lenskit.eval.traintest.recommend

Class ItemSelector

java.lang.Object

org.lenskit.eval.traintest.recommend.ItemSelector

Direct Known Subclasses:

ItemSelector.GroovyItemSelector

public abstract class ItemSelector
extends java.lang.Object

Select items for use in recommendation or

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ItemSelector.GroovyItemSelector Item selector based on a Groovy script.
static class	ItemSelector.ItemSelectScript Base class defining the environment in which item selectors are evaluated.

Constructor Summary

Constructors

Constructor and Description
ItemSelector()

Method Summary

Modifier and Type	Method and Description
static ItemSelector	allItems()
static ItemSelector	compileSelector(java.lang.String expr) Compile an item selector from a Groovy expression.
static ItemSelector	fixed(long... items)
static ItemSelector	fixed(LongSet items) Get an item selector that returns a fixed set of items.
static ItemSelector	nullSelector() Get an item selector that returns null.
abstract LongSet	selectItems(LongSet universe, Recommender recommender, TestUser user) Select a set of items for recommendation.
static ItemSelector	userTestItems()
static ItemSelector	userTrainItems()

Methods inherited from class java.lang.Object

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

Constructor Detail

ItemSelector

public ItemSelector()

Method Detail

selectItems

public abstract LongSet selectItems(LongSet universe,
                                    Recommender recommender,
                                    TestUser user)

Select a set of items for recommendation.

Parameters:

universe - The universe of all items.

recommender - The recommender, in case additional information is needed form it.

user - The user being tested.

Returns:

A set of items.

nullSelector

public static ItemSelector nullSelector()

Get an item selector that returns null. When used as the set of candidate items, this will select the default candidate set.

Returns:

An item selector that always returns null.

fixed

public static ItemSelector fixed(LongSet items)

Get an item selector that returns a fixed set of items.

Parameters:

items - The items to return.

fixed

public static ItemSelector fixed(long... items)

compileSelector

public static ItemSelector compileSelector(java.lang.String expr)

Compile an item selector from a Groovy expression. Two useful objects are available to this expression:

allItems

A set of all item IDs in the system.

user

The current user, as a TestUser.

The expression is compiled as a script with a base class of ItemSelector.ItemSelectScript; see that for more details.

Parameters:

expr - A Groovy expression. Can be null, in which case nullSelector() is returned.

allItems

public static ItemSelector allItems()

userTestItems

public static ItemSelector userTestItems()

userTrainItems

public static ItemSelector userTrainItems()