Module org.apache.lucene.core

Package org.apache.lucene.util

Class MergedIterator<T extends Comparable<T>>

java.lang.Object

org.apache.lucene.util.MergedIterator<T>

All Implemented Interfaces:

Iterator<T>

public final class MergedIterator<T extends Comparable<T>>
extends Object
implements Iterator<T>

Provides a merged sorted view from several sorted iterators.

If built with removeDuplicates set to true and an element appears in multiple iterators then it is deduplicated, that is this iterator returns the sorted union of elements.

If built with removeDuplicates set to false then all elements in all iterators are returned.

Caveats:

• The behavior is undefined if the iterators are not actually sorted.
• Null elements are unsupported.
• If removeDuplicates is set to true and if a single iterator contains duplicates then they will not be deduplicated.
• When elements are deduplicated it is not defined which one is returned.
• If removeDuplicates is set to false then the order in which duplicates are returned isn't defined.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	MergedIterator.SubIterator<I extends Comparable<I>>
private static class	MergedIterator.TermMergeQueue<C extends Comparable<C>>

Field Summary

Fields

Modifier and Type	Field	Description
private T	current
private int	numTop
private final MergedIterator.TermMergeQueue<T>	queue
private final boolean	removeDuplicates
private final MergedIterator.SubIterator<T>[]	top

Constructor Summary

Constructors

Constructor	Description
MergedIterator(boolean removeDuplicates, Iterator<T>... iterators)
MergedIterator(Iterator<T>... iterators)

Method Summary

Modifier and Type	Method	Description
boolean	hasNext()
T	next()
private void	pullTop()
private void	pushTop()
void	remove()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Field Details

current

private T extends Comparable<T> current

queue

private final MergedIterator.TermMergeQueue<T extends Comparable<T>> queue

top

private final MergedIterator.SubIterator<T extends Comparable<T>>[] top

removeDuplicates

private final boolean removeDuplicates

numTop

private int numTop

Constructor Details

MergedIterator

public MergedIterator(Iterator<T>... iterators)

MergedIterator

public MergedIterator(boolean removeDuplicates,
 Iterator<T>... iterators)

Method Details

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<T extends Comparable<T>>

next

public T next()

Specified by:

next in interface Iterator<T extends Comparable<T>>

remove

public void remove()

Specified by:

remove in interface Iterator<T extends Comparable<T>>

pullTop

private void pullTop()

pushTop

private void pushTop()