es.uam.eps.ir.ranksys.core.util.topn

Class TopN<T>

java.lang.Object

java.util.AbstractCollection<T>

es.uam.eps.ir.ranksys.core.util.topn.AbstractTopN<T>

es.uam.eps.ir.ranksys.core.util.topn.TopN<T>

Type Parameters:

T - type of the objects in the heap

All Implemented Interfaces:

Iterable<T>, Collection<T>

public class TopN<T>
extends AbstractTopN<T>

Bounded min-heap to keep just the top-n greatest objects.

Author:

Saúl Vargas (saul.vargas@uam.es)

Field Summary

Fields inherited from class es.uam.eps.ir.ranksys.core.util.topn.AbstractTopN

capacity, size

Constructor Summary

Constructors

Constructor and Description
TopN(int capacity) Constructor that assumes that the class T implements the Comparable interface.
TopN(int capacity, Comparator<T> cmp) Constructor in which the comparator is specified.

Method Summary

Modifier and Type	Method and Description
protected int	compare(int i, int j) Compares the i-th element of the heap with the j-th element in the heap.
protected int	compare(int i, T e) Compares the i-th element of the heap with the element
protected T	get(int i) Returns the i-th element in the heap.
protected void	set(int i, T e) Sets the element in the i-th position of the heap.
protected void	swap(int i, int j) Swaps the elements in the i-th and j-th element in the heap.

Methods inherited from class es.uam.eps.ir.ranksys.core.util.topn.AbstractTopN

add, iterator, peek, reverseIterator, reverseStream, size, sort

Methods inherited from class java.util.AbstractCollection

addAll, clear, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

equals, hashCode, parallelStream, removeIf, spliterator, stream

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

TopN

public TopN(int capacity)

Constructor that assumes that the class T implements the Comparable interface.

Parameters:

capacity - maximum capacity of the heap

TopN

public TopN(int capacity,
            Comparator<T> cmp)

Constructor in which the comparator is specified.

Parameters:

capacity - maximum capacity of the heap

cmp - comparator

Method Detail

get

protected T get(int i)

Description copied from class: AbstractTopN

Returns the i-th element in the heap.

Specified by:

get in class AbstractTopN<T>

Parameters:

i - index of the element

Returns:

the element in the heap

set

protected void set(int i,
                   T e)

Description copied from class: AbstractTopN

Sets the element in the i-th position of the heap.

Specified by:

set in class AbstractTopN<T>

Parameters:

i - index

e - element

compare

protected int compare(int i,
                      T e)

Description copied from class: AbstractTopN

Compares the i-th element of the heap with the element

Specified by:

compare in class AbstractTopN<T>

Parameters:

i - index

e - element

Returns:

a number less than, equal to or greater than zero if the i-th element in the heap is smaller, equal or greater than the element.

compare

protected int compare(int i,
                      int j)

Description copied from class: AbstractTopN

Compares the i-th element of the heap with the j-th element in the heap.

Specified by:

compare in class AbstractTopN<T>

Parameters:

i - index

j - index

Returns:

a number less than, equal to or greater than zero if the i-th element in the heap is smaller, equal or greater than j-th in the heap.

swap

protected void swap(int i,
                    int j)

Description copied from class: AbstractTopN

Swaps the elements in the i-th and j-th element in the heap.

Specified by:

swap in class AbstractTopN<T>

Parameters:

i - index

j - index