Package org.apache.cassandra.io.tries

Class ReverseValueIterator<Concrete extends ReverseValueIterator<Concrete>>

java.lang.Object

org.apache.cassandra.io.tries.Walker<Concrete>

org.apache.cassandra.io.tries.ReverseValueIterator<Concrete>

All Implemented Interfaces:

AutoCloseable

@NotThreadSafe
public class ReverseValueIterator<Concrete extends ReverseValueIterator<Concrete>>
extends Walker<Concrete>

Thread-unsafe reverse value iterator for on-disk tries. Uses the assumptions of Walker.

The main utility of this class is the nextPayloadedNode() method, which lists all nodes that contain a payload within the requested bounds. The treatment of the bounds is non-standard (see ReverseValueIterator(Rebufferer, long, ByteComparable, ByteComparable, boolean)), necessary to properly walk tries of prefixes and separators.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.cassandra.io.tries.Walker

Walker.Extractor<RESULT,VALUE>, Walker.PayloadToString, Walker.TransitionBytesCollector

Field Summary

Fields inherited from class org.apache.cassandra.io.tries.Walker

buf, BYTE_COMPARABLE_VERSION, greaterBranch, lesserBranch, nodeType, NONE, position, root

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ReverseValueIterator(Rebufferer source, long root)
protected	ReverseValueIterator(Rebufferer source, long root, ByteComparable start, ByteComparable end, boolean admitPrefix)	Constrained iterator.

Method Summary

Modifier and Type	Method	Description
protected long	nextPayloadedNode()	Returns the position of the next node with payload contained in the iterated span.

Methods inherited from class org.apache.cassandra.io.tries.Walker

close, dumpTrie, follow, followWithGreater, followWithLesser, getMaxTerm, getMinTerm, go, goMax, goMin, greaterTransition, hasChildren, hasPayload, lastTransition, lesserTransition, nodeSize, nodeTypeOrdinal, payloadFlags, payloadPosition, prefix, prefixAndNeighbours, search, toString, transition, transitionByte, transitionRange

Methods inherited from class java.lang.Object

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

Constructor Details

ReverseValueIterator

protected ReverseValueIterator(Rebufferer source,
 long root)

ReverseValueIterator

protected ReverseValueIterator(Rebufferer source,
 long root,
 ByteComparable start,
 ByteComparable end,
 boolean admitPrefix)

Constrained iterator. The end position is always treated as inclusive, and we have two possible treatments for the start:

• When admitPrefix=false, exact matches and any prefixes of the start are excluded.
• When admitPrefix=true, the longest prefix of the start present in the trie is also included, provided that there is no entry in the trie between that prefix and the start. An exact match also satisfies this and is included.

This behaviour is shared with the forward counterpart ValueIterator.

Method Details

nextPayloadedNode

protected long nextPayloadedNode()

Returns the position of the next node with payload contained in the iterated span.