Package org.apache.druid.segment.data

Class Offset

java.lang.Object

org.apache.druid.segment.data.Offset

All Implemented Interfaces:

Cloneable, HotLoopCallee, ReadableOffset

Direct Known Subclasses:

BitmapOffset, FilteredOffset, QueryableIndexCursorHolder.TimestampCheckingOffset, SimpleSettableOffset

@SubclassesMustBePublic
public abstract class Offset
extends Object
implements ReadableOffset, Cloneable

The "mutable" version of a ReadableOffset. Introduces "increment()" and "withinBounds()" methods, which are very similar to "next()" and "hasNext()" on the Iterator interface except increment() does not return a value. This class is not thread-safe, all it's methods, including reset() and clone(), must be called from a single thread. Annotated with SubclassesMustBePublic because Offset occurrences are replaced with a subclass in Historical1SimpleDoubleAggPooledTopNScannerPrototype and HistoricalSingleValueDimSelector1SimpleDoubleAggPooledTopNScannerPrototype during specialization, and specialized version of those prototypes must be able to any subclass of Offset. This interface is the core "pointer" interface that is used to create ColumnValueSelectors over historical segments. It's counterpart for incremental index is IncrementalIndexRowHolder.

Constructor Summary

Constructors

Constructor	Description
Offset()

Method Summary

Modifier and Type	Method	Description
Offset	clone()
abstract ReadableOffset	getBaseReadableOffset()	Returns the same offset ("this") or a readable "view" of this offset, which always returns the same value from ReadableOffset.getOffset(), as this offset.
abstract void	increment()	Move to next offset
abstract void	reset()	Resets the Offset to the position it was created or cloned with.
abstract boolean	withinBounds()	Check if current offset position is within the valid range

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.druid.query.monomorphicprocessing.HotLoopCallee

inspectRuntimeShape

Methods inherited from interface org.apache.druid.segment.data.ReadableOffset

getOffset

Constructor Details

Offset

public Offset()

Method Details

increment

@CalledFromHotLoop
public abstract void increment()

Move to next offset

withinBounds

@CalledFromHotLoop
public abstract boolean withinBounds()

Check if current offset position is within the valid range

reset

public abstract void reset()

Resets the Offset to the position it was created or cloned with.

getBaseReadableOffset

public abstract ReadableOffset getBaseReadableOffset()

Returns the same offset ("this") or a readable "view" of this offset, which always returns the same value from ReadableOffset.getOffset(), as this offset. This method is useful for "unwrapping" such offsets as FilteredOffset and reduce reference indirection, when only ReadableOffset API is needed.

clone

public Offset clone()

Overrides:

clone in class Object