org.apache.mahout.cf.taste.impl.model

Class GenericUserPreferenceArray

java.lang.Object

org.apache.mahout.cf.taste.impl.model.GenericUserPreferenceArray

All Implemented Interfaces:

Serializable, Cloneable, Iterable<Preference>, PreferenceArray

public final class GenericUserPreferenceArray
extends Object
implements PreferenceArray

Like GenericItemPreferenceArray but stores preferences for one user (all user IDs the same) rather than one item.

This implementation maintains two parallel arrays, of item IDs and values. The idea is to save allocating Preference objects themselves. This saves the overhead of Preference objects but also duplicating the user ID value.

See Also:

BooleanUserPreferenceArray, GenericItemPreferenceArray, GenericPreference, Serialized Form

Constructor Summary

Constructors

Constructor and Description
GenericUserPreferenceArray(int size)
GenericUserPreferenceArray(List<? extends Preference> prefs)

Method Summary

Modifier and Type	Method and Description
GenericUserPreferenceArray	clone()
boolean	equals(Object other)
Preference	get(int i)
long[]	getIDs()
long	getItemID(int i)
long	getUserID(int i)
float	getValue(int i)
int	hashCode()
boolean	hasPrefWithItemID(long itemID)
boolean	hasPrefWithUserID(long userID)
Iterator<Preference>	iterator()
int	length()
void	set(int i, Preference pref) Sets preference at i from information in the given Preference
void	setItemID(int i, long itemID) Sets item ID for preference at i.
void	setUserID(int i, long userID) Sets user ID for preference at i.
void	setValue(int i, float value) Sets preference value for preference at i.
void	sortByItem() Sorts underlying array by item ID, ascending.
void	sortByUser() Sorts underlying array by user ID, ascending.
void	sortByValue() Sorts underlying array by preference value, ascending.
void	sortByValueReversed() Sorts underlying array by preference value, descending.
String	toString()

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

GenericUserPreferenceArray

public GenericUserPreferenceArray(int size)

GenericUserPreferenceArray

public GenericUserPreferenceArray(List<? extends Preference> prefs)

Method Detail

length

public int length()

Specified by:

length in interface PreferenceArray

Returns:

size of length of the "array"

get

public Preference get(int i)

Specified by:

get in interface PreferenceArray

Parameters:

i - index

Returns:

a materialized Preference representation of the preference at i

set

public void set(int i,
                Preference pref)

Description copied from interface: PreferenceArray

Sets preference at i from information in the given Preference

Specified by:

set in interface PreferenceArray

getUserID

public long getUserID(int i)

Specified by:

getUserID in interface PreferenceArray

Parameters:

i - index

Returns:

user ID from preference at i

setUserID

public void setUserID(int i,
                      long userID)

Sets user ID for preference at i. Note that this method will actually set the user ID for all preferences.

Specified by:

setUserID in interface PreferenceArray

Parameters:

i - index

userID - new user ID

getItemID

public long getItemID(int i)

Specified by:

getItemID in interface PreferenceArray

Parameters:

i - index

Returns:

item ID from preference at i

setItemID

public void setItemID(int i,
                      long itemID)

Description copied from interface: PreferenceArray

Sets item ID for preference at i.

Specified by:

setItemID in interface PreferenceArray

Parameters:

i - index

itemID - new item ID

getIDs

public long[] getIDs()

Specified by:

getIDs in interface PreferenceArray

Returns:

all item IDs

getValue

public float getValue(int i)

Specified by:

getValue in interface PreferenceArray

Parameters:

i - index

Returns:

preference value from preference at i

setValue

public void setValue(int i,
                     float value)

Description copied from interface: PreferenceArray

Sets preference value for preference at i.

Specified by:

setValue in interface PreferenceArray

Parameters:

i - index

value - new preference value

sortByUser

public void sortByUser()

Description copied from interface: PreferenceArray

Sorts underlying array by user ID, ascending.

Specified by:

sortByUser in interface PreferenceArray

sortByItem

public void sortByItem()

Description copied from interface: PreferenceArray

Sorts underlying array by item ID, ascending.

Specified by:

sortByItem in interface PreferenceArray

sortByValue

public void sortByValue()

Description copied from interface: PreferenceArray

Sorts underlying array by preference value, ascending.

Specified by:

sortByValue in interface PreferenceArray

sortByValueReversed

public void sortByValueReversed()

Description copied from interface: PreferenceArray

Sorts underlying array by preference value, descending.

Specified by:

sortByValueReversed in interface PreferenceArray

hasPrefWithUserID

public boolean hasPrefWithUserID(long userID)

Specified by:

hasPrefWithUserID in interface PreferenceArray

Parameters:

userID - user ID

Returns:

true if array contains a preference with given user ID

hasPrefWithItemID

public boolean hasPrefWithItemID(long itemID)

Specified by:

hasPrefWithItemID in interface PreferenceArray

Parameters:

itemID - item ID

Returns:

true if array contains a preference with given item ID

clone

public GenericUserPreferenceArray clone()

Specified by:

clone in interface PreferenceArray

Overrides:

clone in class Object

Returns:

independent copy of this object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Overrides:

equals in class Object

iterator

public Iterator<Preference> iterator()

Specified by:

iterator in interface Iterable<Preference>

toString

public String toString()

Overrides:

toString in class Object