org.grouplens.lenskit.data.dao

Interface ItemEventDAO

All Known Implementing Classes:

BinaryRatingDAO, JDBCRatingDAO, PrefetchingItemEventDAO, RatingSnapshotDAO

@DefaultImplementation(value=PrefetchingItemEventDAO.class)
public interface ItemEventDAO

DAO to retrieve events by item.

Since:

1.3

Method Summary

Modifier and Type	Method and Description
List<Event>	getEventsForItem(long item) Get the events for a specific item.
<E extends Event> List<E>	getEventsForItem(long item, Class<E> type) Get the events for a specific item, filtering by type.
LongSet	getUsersForItem(long item) Get the users who have interacted with an item.
Cursor<ItemEventCollection<Event>>	streamEventsByItem() Stream events grouped by item.
<E extends Event> Cursor<ItemEventCollection<E>>	streamEventsByItem(Class<E> type) Stream events grouped by item.

Method Detail

streamEventsByItem

Cursor<ItemEventCollection<Event>> streamEventsByItem()

Stream events grouped by item.

Returns:

A cursor iterating over the events from all items. If an item exists but does not have any events, it may or may not be included depending on the DAO implementation.

streamEventsByItem

<E extends Event> Cursor<ItemEventCollection<E>> streamEventsByItem(Class<E> type)

Stream events grouped by item.

Parameters:

type - The type of item to look for.

Returns:

A cursor iterating over the events of type type from all items. If an item exists but does not have any events, it may or may not be included depending on the DAO implementation.

getEventsForItem

List<Event> getEventsForItem(long item)

Get the events for a specific item.

Parameters:

item - The item ID.

Returns:

The item's history, or null if the item is unknown.

getEventsForItem

@Nullable
<E extends Event> List<E> getEventsForItem(long item,
                                                     Class<E> type)

Get the events for a specific item, filtering by type.

Parameters:

item - The item ID.

type - The type of events to retrieve.

Returns:

The item's history, or null if the item is unknown.

getUsersForItem

@Nullable
LongSet getUsersForItem(long item)

Get the users who have interacted with an item.

Parameters:

item - The item ID.

Returns:

The set of users who have interacted with this item, or null if the item is unknown.