org.apache.mahout.cf.taste.impl.similarity.jdbc
Class AbstractJDBCItemSimilarity
java.lang.Object
org.apache.mahout.cf.taste.impl.common.jdbc.AbstractJDBCComponent
org.apache.mahout.cf.taste.impl.similarity.jdbc.AbstractJDBCItemSimilarity
- All Implemented Interfaces:
- Refreshable, ItemSimilarity
- Direct Known Subclasses:
- MySQLJDBCItemSimilarity
public abstract class AbstractJDBCItemSimilarity
- extends AbstractJDBCComponent
- implements ItemSimilarity
An ItemSimilarity
which draws pre-computed item-item similarities from a database table via JDBC.
Constructor Summary |
protected |
AbstractJDBCItemSimilarity(javax.sql.DataSource dataSource,
java.lang.String getItemItemSimilaritySQL)
|
protected |
AbstractJDBCItemSimilarity(javax.sql.DataSource dataSource,
java.lang.String similarityTable,
java.lang.String itemAIDColumn,
java.lang.String itemBIDColumn,
java.lang.String similarityColumn,
java.lang.String getItemItemSimilaritySQL)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
AbstractJDBCItemSimilarity
protected AbstractJDBCItemSimilarity(javax.sql.DataSource dataSource,
java.lang.String getItemItemSimilaritySQL)
AbstractJDBCItemSimilarity
protected AbstractJDBCItemSimilarity(javax.sql.DataSource dataSource,
java.lang.String similarityTable,
java.lang.String itemAIDColumn,
java.lang.String itemBIDColumn,
java.lang.String similarityColumn,
java.lang.String getItemItemSimilaritySQL)
getSimilarityTable
protected java.lang.String getSimilarityTable()
getItemAIDColumn
protected java.lang.String getItemAIDColumn()
getItemBIDColumn
protected java.lang.String getItemBIDColumn()
getSimilarityColumn
protected java.lang.String getSimilarityColumn()
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]
- Throws:
TasteException
- if an error occurs while accessing the data
refresh
public void refresh(java.util.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.
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