org.grouplens.lenskit.data.dao

Class PrefetchingUserDAO

java.lang.Object

org.grouplens.lenskit.data.dao.PrefetchingUserDAO

All Implemented Interfaces:

UserDAO, Describable

public final class PrefetchingUserDAO
extends Object
implements UserDAO, Describable

User DAO that streams the events to get user information. The user set is fetched and memorized once for each instance of this class.

Since:

2.0

Constructor Summary

Constructors

Constructor and Description
PrefetchingUserDAO(EventDAO events)

Method Summary

Modifier and Type	Method and Description
void	describeTo(DescriptionWriter writer) Write this class's description to a sink.
LongSet	getUserIds() Get all known user IDs.
static Function<EventDAO,UserDAO>	wrapper() A function that wraps an event DAO in a prefetching user DAO.

Methods inherited from class java.lang.Object

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

Constructor Detail

PrefetchingUserDAO

@Inject
public PrefetchingUserDAO(EventDAO events)

Method Detail

wrapper

public static Function<EventDAO,UserDAO> wrapper()

A function that wraps an event DAO in a prefetching user DAO. If the DAO already implements UserDAO, it is returned unwrapped.

Returns:

A wrapper function to make user DAOs from event DAOs.

getUserIds

public LongSet getUserIds()

Description copied from interface: UserDAO

Get all known user IDs.

Specified by:

getUserIds in interface UserDAO

Returns:

The set of known user IDs.

describeTo

public void describeTo(DescriptionWriter writer)

Description copied from interface: Describable

Write this class's description to a sink. Anything relevant to this object's identity should be digested; the idea is that, barring hash collisions, two objects with the same digest are equivalent. Used for things like deterministically generating cache file names.

Specified by:

describeTo in interface Describable

Parameters:

writer - The description writer to use.