org.apache.mahout.cf.taste.impl.similarity.jdbc
Class MySQLJDBCInMemoryItemSimilarity
java.lang.Object
org.apache.mahout.cf.taste.impl.common.jdbc.AbstractJDBCComponent
org.apache.mahout.cf.taste.impl.similarity.jdbc.MySQLJDBCInMemoryItemSimilarity
- All Implemented Interfaces:
- Refreshable, ItemSimilarity
public class MySQLJDBCInMemoryItemSimilarity
- extends AbstractJDBCComponent
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
MySQLJDBCInMemoryItemSimilarity
public MySQLJDBCInMemoryItemSimilarity()
throws TasteException
- Throws:
TasteException
MySQLJDBCInMemoryItemSimilarity
public MySQLJDBCInMemoryItemSimilarity(String dataSourceName)
throws TasteException
- Throws:
TasteException
MySQLJDBCInMemoryItemSimilarity
public MySQLJDBCInMemoryItemSimilarity(DataSource dataSource)
MySQLJDBCInMemoryItemSimilarity
public MySQLJDBCInMemoryItemSimilarity(DataSource dataSource,
String getAllItemSimilaritiesSQL)
getFetchSize
protected int getFetchSize()
- Overrides:
getFetchSize
in class AbstractJDBCComponent
itemSimilarity
public double itemSimilarity(long itemID1,
long itemID2)
throws TasteException
- Description copied from interface:
ItemSimilarity
Returns the degree of similarity, of two items, based on the preferences that users have expressed for
the items.
- Specified by:
itemSimilarity
in interface ItemSimilarity
- Parameters:
itemID1
- first item IDitemID2
- second item ID
- Returns:
- similarity between the items, in [-1,1] or
Double.NaN
similarity is unknown
- Throws:
NoSuchItemException
- if either item is known to be non-existent in the data
TasteException
- if an error occurs while accessing the data
itemSimilarities
public double[] itemSimilarities(long itemID1,
long[] itemID2s)
throws TasteException
- Description copied from interface:
ItemSimilarity
A bulk-get version of ItemSimilarity.itemSimilarity(long, long)
.
- Specified by:
itemSimilarities
in interface ItemSimilarity
- Parameters:
itemID1
- first item IDitemID2s
- second item IDs to compute similarity with
- Returns:
- similarity between itemID1 and other items
- Throws:
NoSuchItemException
- if any item is known to be non-existent in the data
TasteException
- if an error occurs while accessing the data
allSimilarItemIDs
public long[] allSimilarItemIDs(long itemID)
throws TasteException
- Specified by:
allSimilarItemIDs
in interface ItemSimilarity
- Returns:
- all IDs of similar items, in no particular order
- Throws:
TasteException
refresh
public void refresh(Collection<Refreshable> alreadyRefreshed)
- Description copied from interface:
Refreshable
Triggers "refresh" -- whatever that means -- of the implementation. The general contract is that any
should always leave itself in a consistent, operational state, and that the refresh
atomically updates internal state from old to new.
- Specified by:
refresh
in interface Refreshable
- Parameters:
alreadyRefreshed
- s that are known to have already been
refreshed as a result of an initial call to a method on some
object. This ensure that objects in a refresh dependency graph aren't refreshed twice
needlessly.
reload
protected void reload()
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