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
 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


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