org.apache.mahout.cf.taste.model

Interface PreferenceArray

All Superinterfaces:

Cloneable, Iterable<Preference>, Serializable

All Known Implementing Classes:

BooleanItemPreferenceArray, BooleanUserPreferenceArray, GenericItemPreferenceArray, GenericUserPreferenceArray

public interface PreferenceArray
extends Cloneable, Serializable, Iterable<Preference>

An alternate representation of an array of Preference. Implementations, in theory, can produce a more memory-efficient representation.

Method Summary

Methods

Modifier and Type	Method and Description
PreferenceArray	clone()
Preference	get(int i)
long[]	getIDs()
long	getItemID(int i)
long	getUserID(int i)
float	getValue(int i)
boolean	hasPrefWithItemID(long itemID)
boolean	hasPrefWithUserID(long userID)
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.

Methods inherited from interface java.lang.Iterable

iterator

Method Detail

length

int length()

Returns:

size of length of the "array"

get

Preference get(int i)

Parameters:

i - index

Returns:

a materialized Preference representation of the preference at i

set

void set(int i,
       Preference pref)

Sets preference at i from information in the given Preference

Parameters:

i -

pref -

getUserID

long getUserID(int i)

Parameters:

i - index

Returns:

user ID from preference at i

setUserID

void setUserID(int i,
             long userID)

Sets user ID for preference at i.

Parameters:

i - index

userID - new user ID

getItemID

long getItemID(int i)

Parameters:

i - index

Returns:

item ID from preference at i

setItemID

void setItemID(int i,
             long itemID)

Sets item ID for preference at i.

Parameters:

i - index

itemID - new item ID

getIDs

long[] getIDs()

Returns:

all user or item IDs

getValue

float getValue(int i)

Parameters:

i - index

Returns:

preference value from preference at i

setValue

void setValue(int i,
            float value)

Sets preference value for preference at i.

Parameters:

i - index

value - new preference value

clone

PreferenceArray clone()

Returns:

independent copy of this object

sortByUser

void sortByUser()

Sorts underlying array by user ID, ascending.

sortByItem

void sortByItem()

Sorts underlying array by item ID, ascending.

sortByValue

void sortByValue()

Sorts underlying array by preference value, ascending.

sortByValueReversed

void sortByValueReversed()

Sorts underlying array by preference value, descending.

hasPrefWithUserID

boolean hasPrefWithUserID(long userID)

Parameters:

userID - user ID

Returns:

true if array contains a preference with given user ID

hasPrefWithItemID

boolean hasPrefWithItemID(long itemID)

Parameters:

itemID - item ID

Returns:

true if array contains a preference with given item ID