org.apache.mahout.cf.taste.impl.recommender.slopeone.jdbc

Class AbstractJDBCDiffStorage

java.lang.Object

org.apache.mahout.cf.taste.impl.common.jdbc.AbstractJDBCComponent

org.apache.mahout.cf.taste.impl.recommender.slopeone.jdbc.AbstractJDBCDiffStorage

All Implemented Interfaces:

Refreshable, DiffStorage

Direct Known Subclasses:

MySQLJDBCDiffStorage

public abstract class AbstractJDBCDiffStorage
extends AbstractJDBCComponent
implements DiffStorage

A DiffStorage which stores diffs in a database. Database-specific implementations subclass this abstract class. Note that this implementation has a fairly particular dependence on the DataModel used; it needs a JDBCDataModel attached to the same database since its efficient operation depends on accessing preference data in the database directly.

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_AVERAGE_DIFF_COLUMN
static String	DEFAULT_COUNT_COLUMN
static String	DEFAULT_DIFF_TABLE
static String	DEFAULT_ITEM_A_COLUMN
static String	DEFAULT_ITEM_B_COLUMN
static String	DEFAULT_STDEV_COLUMN

Fields inherited from class org.apache.mahout.cf.taste.impl.common.jdbc.AbstractJDBCComponent

DEFAULT_DATASOURCE_NAME

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractJDBCDiffStorage(JDBCDataModel dataModel, String getDiffSQL, String getDiffsSQL, String getAverageItemPrefSQL, String getDiffsAffectedByUserSQL, String[] updateDiffSQLs, String updateOneDiffSQL, String addDiffSQL, String removeDiffSQL, String getRecommendableItemsSQL, String deleteDiffsSQL, String createDiffsSQL, String diffsExistSQL, int minDiffCount)

Method Summary

Methods

Modifier and Type	Method and Description
void	addItemPref(long userID, long itemID, float prefValue)
RunningAverage	getAverageItemPref(long itemID)
RunningAverage	getDiff(long itemID1, long itemID2)
RunningAverage[]	getDiffs(long userID, long itemID, PreferenceArray prefs)
FastIDSet	getRecommendableItemIDs(long userID)
void	refresh(Collection<Refreshable> alreadyRefreshed)
void	removeItemPref(long userID, long itemID, float prefValue)
void	updateItemPref(long itemID, float prefDelta) Note that this implementation does not update standard deviations.

Methods inherited from class org.apache.mahout.cf.taste.impl.common.jdbc.AbstractJDBCComponent

checkNotNullAndLog, checkNotNullAndLog, getFetchSize, lookupDataSource

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_DIFF_TABLE

public static final String DEFAULT_DIFF_TABLE

See Also:

Constant Field Values

DEFAULT_ITEM_A_COLUMN

public static final String DEFAULT_ITEM_A_COLUMN

See Also:

Constant Field Values

DEFAULT_ITEM_B_COLUMN

public static final String DEFAULT_ITEM_B_COLUMN

See Also:

Constant Field Values

DEFAULT_COUNT_COLUMN

public static final String DEFAULT_COUNT_COLUMN

See Also:

Constant Field Values

DEFAULT_AVERAGE_DIFF_COLUMN

public static final String DEFAULT_AVERAGE_DIFF_COLUMN

See Also:

Constant Field Values

DEFAULT_STDEV_COLUMN

public static final String DEFAULT_STDEV_COLUMN

See Also:

Constant Field Values

Constructor Detail

AbstractJDBCDiffStorage

protected AbstractJDBCDiffStorage(JDBCDataModel dataModel,
                       String getDiffSQL,
                       String getDiffsSQL,
                       String getAverageItemPrefSQL,
                       String getDiffsAffectedByUserSQL,
                       String[] updateDiffSQLs,
                       String updateOneDiffSQL,
                       String addDiffSQL,
                       String removeDiffSQL,
                       String getRecommendableItemsSQL,
                       String deleteDiffsSQL,
                       String createDiffsSQL,
                       String diffsExistSQL,
                       int minDiffCount)
                           throws TasteException

Throws:

TasteException

Method Detail

getDiff

public RunningAverage getDiff(long itemID1,
                     long itemID2)
                       throws TasteException

Specified by:

getDiff in interface DiffStorage

Throws:

TasteException

getDiffs

public RunningAverage[] getDiffs(long userID,
                        long itemID,
                        PreferenceArray prefs)
                          throws TasteException

Specified by:

getDiffs in interface DiffStorage

Throws:

TasteException

getAverageItemPref

public RunningAverage getAverageItemPref(long itemID)
                                  throws TasteException

Specified by:

getAverageItemPref in interface DiffStorage

Throws:

TasteException

addItemPref

public void addItemPref(long userID,
               long itemID,
               float prefValue)
                 throws TasteException

Specified by:

addItemPref in interface DiffStorage

Throws:

TasteException

updateItemPref

public void updateItemPref(long itemID,
                  float prefDelta)
                    throws TasteException

Note that this implementation does not update standard deviations. This would be expensive relative to the value of slightly adjusting these values, which are merely used as weighted. Rebuilding the diffs table will update standard deviations.

Specified by:

updateItemPref in interface DiffStorage

Throws:

TasteException

removeItemPref

public void removeItemPref(long userID,
                  long itemID,
                  float prefValue)
                    throws TasteException

Specified by:

removeItemPref in interface DiffStorage

Throws:

TasteException

getRecommendableItemIDs

public FastIDSet getRecommendableItemIDs(long userID)
                                  throws TasteException

Specified by:

getRecommendableItemIDs in interface DiffStorage

Throws:

TasteException

refresh

public void refresh(Collection<Refreshable> alreadyRefreshed)

Specified by:

refresh in interface Refreshable