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

Class AbstractTopN<T>

java.lang.Object

java.util.AbstractCollection<T>

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

Type Parameters:

T - type of the objects in the heap

All Implemented Interfaces:

Iterable<T>, Collection<T>

Direct Known Subclasses:

IntDoubleTopN, ObjectDoubleTopN, TopN

public abstract class AbstractTopN<T>
extends AbstractCollection<T>

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

Author:

Saúl Vargas (saul.vargas@uam.es)

Field Summary

Fields

Modifier and Type	Field and Description
protected int	capacity Maximum capacity of the heap.
protected int	size Current size of the heap.

Constructor Summary

Constructors

Constructor and Description
AbstractTopN(int capacity) Constructor

Method Summary

Modifier and Type	Method and Description
boolean	add(T elem)
protected abstract int	compare(int i, int j) Compares the i-th element of the heap with the j-th element in the heap.
protected abstract int	compare(int i, T e) Compares the i-th element of the heap with the element
protected abstract T	get(int i) Returns the i-th element in the heap.
Iterator<T>	iterator()
T	peek() Returns the element at the top of the heap.
Iterator<T>	reverseIterator() Iterates over the elements of the heap in reverse order.
Stream<T>	reverseStream() Creates a stream in reverse order.
protected abstract void	set(int i, T e) Sets the element in the i-th position of the heap.
int	size()
void	sort() Sorts the heap in inverse order (from smallest to greatest).
protected abstract void	swap(int i, int j) Swaps the elements in the i-th and j-th element in the heap.

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

Field Detail

capacity

protected int capacity

Maximum capacity of the heap.

size

protected int size

Current size of the heap.

Constructor Detail

AbstractTopN

public AbstractTopN(int capacity)

Constructor

Parameters:

capacity - maximum capacity of the heap

Method Detail

size

public int size()

Specified by:

size in interface Collection<T>

Specified by:

size in class AbstractCollection<T>

peek

public T peek()

Returns the element at the top of the heap.

Returns:

the element at the top of the heap

add

public boolean add(T elem)

Specified by:

add in interface Collection<T>

Overrides:

add in class AbstractCollection<T>

sort

public void sort()

Sorts the heap in inverse order (from smallest to greatest).

iterator

public Iterator<T> iterator()

Specified by:

iterator in interface Iterable<T>

Specified by:

iterator in interface Collection<T>

Specified by:

iterator in class AbstractCollection<T>

reverseIterator

public Iterator<T> reverseIterator()

Iterates over the elements of the heap in reverse order.

Returns:

an iterator in reverse order

reverseStream

public Stream<T> reverseStream()

Creates a stream in reverse order.

Returns:

stream in reverse order

get

protected abstract T get(int i)

Returns the i-th element in the heap.

Parameters:

i - index of the element

Returns:

the element in the heap

set

protected abstract void set(int i,
                            T e)

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

Parameters:

i - index

e - element

compare

protected abstract int compare(int i,
                               T e)

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

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 abstract int compare(int i,
                               int j)

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

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 abstract void swap(int i,
                             int j)

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

Parameters:

i - index

j - index