de.lmu.ifi.dbs.elki.result
Class OrderingFromAssociation<T extends Comparable<T>,O extends DatabaseObject>

java.lang.Object
  de.lmu.ifi.dbs.elki.result.OrderingFromAssociation<T,O>

Type Parameters:

T - data type of annotation.

O - database object type

All Implemented Interfaces:

OrderingResult, Result

public class OrderingFromAssociation<T extends Comparable<T>,O extends DatabaseObject>
extends Object
implements OrderingResult

Return an ordering result backed by a database. Note that the implementation will sort with O(n lg n) database accesses on average, O(n*n) in worst case to avoid having to store all objects in memory.

Author:

Erich Schubert

Nested Class Summary

protected class	OrderingFromAssociation.DerivedComparator Internally used comparator using a preexisting comparator for the given datatype
protected class	OrderingFromAssociation.ImpliedComparator Internally used comparator retrieving data from the database.

Field Summary

(package private) int	ascending Factor to signal ascending (+1) / descending (-1) order
protected AssociationID<T>	association AssocationID to use
protected Comparator<T>	comparator Internal comparator to use for sorting.
protected Database<O>	db Database

Constructor Summary

OrderingFromAssociation(Database<O> db, AssociationID<T> association)
Minimal constructor, using implied comparator and ascending order.

OrderingFromAssociation(Database<O> db, AssociationID<T> association, boolean descending)
Constructor without comparator

OrderingFromAssociation(Database<O> db, AssociationID<T> association, Comparator<T> comparator, boolean descending)
Full Constructor (with comparator)

Method Summary

Iterator<Integer>

iter(Collection<Integer> ids) Sort the given collection of IDs and return an iterator for the result.

Methods inherited from class java.lang.Object

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

Field Detail

db

protected Database<O extends DatabaseObject> db

Database

association

protected AssociationID<T extends Comparable<T>> association

AssocationID to use

comparator

protected Comparator<T extends Comparable<T>> comparator

Internal comparator to use for sorting.

ascending

int ascending

Factor to signal ascending (+1) / descending (-1) order

Constructor Detail

OrderingFromAssociation

public OrderingFromAssociation(Database<O> db,
                               AssociationID<T> association,
                               Comparator<T> comparator,
                               boolean descending)

Full Constructor (with comparator)

Parameters:

db - Database

association - AssociationID to use

comparator - Comparator for data type used by association

descending - boolean to mark descending ordering (true)

OrderingFromAssociation

public OrderingFromAssociation(Database<O> db,
                               AssociationID<T> association,
                               boolean descending)

Constructor without comparator

Parameters:

db - Database

association - AssociationID to use

descending - boolean to mark descending ordering (true)

OrderingFromAssociation

public OrderingFromAssociation(Database<O> db,
                               AssociationID<T> association)

Minimal constructor, using implied comparator and ascending order.

Parameters:

db - Database

association - AssociationID to use

Method Detail

iter

public Iterator<Integer> iter(Collection<Integer> ids)

Sort the given collection of IDs and return an iterator for the result.

Specified by:

iter in interface OrderingResult

Parameters:

ids - Collection of ids.

Returns:

iterator for sorted array of ids