Package org.apache.druid.segment

Class DictionaryMergingIterator<T extends Comparable<T>>

java.lang.Object

org.apache.druid.segment.DictionaryMergingIterator<T>

All Implemented Interfaces:

Closeable, AutoCloseable, Iterator<T>, CloseableIterator<T>

public class DictionaryMergingIterator<T extends Comparable<T>>
extends Object
implements CloseableIterator<T>

Iterator for merging dictionaries for some comparable type into a single sorted dictionary, useful when merging dictionary encoded columns

Field Summary

Fields

Modifier and Type	Field	Description
protected final IntBuffer[]	conversions
protected int	counter
protected final List<Pair<ByteBuffer,Integer>>	directBufferAllocations
protected final PriorityQueue<Pair<Integer,com.google.common.collect.PeekingIterator<T>>>	pQueue

Constructor Summary

Constructors

Constructor	Description
DictionaryMergingIterator(Indexed<T>[] dimValueLookups, Comparator<Pair<Integer,com.google.common.collect.PeekingIterator<T>>> comparator, boolean useDirect)

Method Summary

Modifier and Type	Method	Description
void	close()
int	getCardinality()
boolean	hasNext()
static <T extends Comparable<T>> Comparator<Pair<Integer,com.google.common.collect.PeekingIterator<T>>>	makePeekingComparator()
protected boolean	needConversion(int index)
T	next()
protected com.google.common.collect.PeekingIterator<T>	transformIndexedIterator(Indexed<T> indexed)
protected T	writeTranslate(Pair<Integer,com.google.common.collect.PeekingIterator<T>> smallest, int counter)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.druid.java.util.common.parsers.CloseableIterator

flatMap, map

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Field Details

conversions

protected final IntBuffer[] conversions

directBufferAllocations

protected final List<Pair<ByteBuffer,Integer>> directBufferAllocations

pQueue

protected final PriorityQueue<Pair<Integer,com.google.common.collect.PeekingIterator<T extends Comparable<T>>>> pQueue

counter

protected int counter

Constructor Details

DictionaryMergingIterator

public DictionaryMergingIterator(Indexed<T>[] dimValueLookups,
 Comparator<Pair<Integer,com.google.common.collect.PeekingIterator<T>>> comparator,
 boolean useDirect)

Method Details

makePeekingComparator

public static <T extends Comparable<T>>
Comparator<Pair<Integer,com.google.common.collect.PeekingIterator<T>>> makePeekingComparator()

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>>

getCardinality

public int getCardinality()

transformIndexedIterator

protected com.google.common.collect.PeekingIterator<T> transformIndexedIterator(Indexed<T> indexed)

needConversion

protected boolean needConversion(int index)

writeTranslate

protected T writeTranslate(Pair<Integer,com.google.common.collect.PeekingIterator<T>> smallest,
 int counter)

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable