com.browseengine.bobo.sort

Class DocIDPriorityQueue

java.lang.Object

com.browseengine.bobo.sort.DocIDPriorityQueue

public class DocIDPriorityQueue
extends Object

Field Summary

Fields

Modifier and Type	Field and Description
int	base
protected org.apache.lucene.search.ScoreDoc[]	heap
int	size

Constructor Summary

Constructors

Constructor and Description
DocIDPriorityQueue(DocComparator comparator, int maxSize, int base)

Method Summary

Methods

Modifier and Type	Method and Description
org.apache.lucene.search.ScoreDoc	add(org.apache.lucene.search.ScoreDoc element) Adds an Object to a PriorityQueue in log(size) time.
void	clear() Removes all entries from the PriorityQueue.
org.apache.lucene.search.ScoreDoc	pop() Removes and returns the least element of the PriorityQueue in log(size) time.
org.apache.lucene.search.ScoreDoc	replace(org.apache.lucene.search.ScoreDoc element)
org.apache.lucene.search.ScoreDoc	replace(org.apache.lucene.search.ScoreDoc newEle, org.apache.lucene.search.ScoreDoc oldEle) Takes O(size) time.
int	size() Returns the number of elements currently stored in the PriorityQueue.
Comparable<?>	sortValue(org.apache.lucene.search.ScoreDoc doc)
org.apache.lucene.search.ScoreDoc	top() Returns the least element of the PriorityQueue in constant time.
org.apache.lucene.search.ScoreDoc	updateTop() Should be called when the Object at top changes values.

Methods inherited from class java.lang.Object

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

Field Detail

size

public int size

heap

protected final org.apache.lucene.search.ScoreDoc[] heap

base

public final int base

Constructor Detail

DocIDPriorityQueue

public DocIDPriorityQueue(DocComparator comparator,
                  int maxSize,
                  int base)

Method Detail

add

public final org.apache.lucene.search.ScoreDoc add(org.apache.lucene.search.ScoreDoc element)

Adds an Object to a PriorityQueue in log(size) time. If one tries to add more objects than maxSize from initialize an ArrayIndexOutOfBoundsException is thrown.

Returns:

the new 'bottom' element in the queue.

sortValue

public Comparable<?> sortValue(org.apache.lucene.search.ScoreDoc doc)

replace

public org.apache.lucene.search.ScoreDoc replace(org.apache.lucene.search.ScoreDoc element)

replace

public org.apache.lucene.search.ScoreDoc replace(org.apache.lucene.search.ScoreDoc newEle,
                                        org.apache.lucene.search.ScoreDoc oldEle)

Takes O(size) time.

Returns:

the 'bottom' element in the queue.

top

public final org.apache.lucene.search.ScoreDoc top()

Returns the least element of the PriorityQueue in constant time.

pop

public final org.apache.lucene.search.ScoreDoc pop()

Removes and returns the least element of the PriorityQueue in log(size) time.

updateTop

public final org.apache.lucene.search.ScoreDoc updateTop()

Should be called when the Object at top changes values. Still log(n) worst case, but it's at least twice as fast to

 pq.top().change();
 pq.updateTop();
 

instead of

 o = pq.pop();
 o.change();
 pq.push(o);
 

Returns:

the new 'top' element.

size

public final int size()

Returns the number of elements currently stored in the PriorityQueue.

clear

public final void clear()

Removes all entries from the PriorityQueue.