io.druid.timeline

Class VersionedIntervalTimeline<VersionType,ObjectType>

java.lang.Object

io.druid.timeline.VersionedIntervalTimeline<VersionType,ObjectType>

All Implemented Interfaces:

TimelineLookup<VersionType,ObjectType>

public class VersionedIntervalTimeline<VersionType,ObjectType>
extends Object
implements TimelineLookup<VersionType,ObjectType>

VersionedIntervalTimeline is a data structure that manages objects on a specific timeline. It associates a jodatime Interval and a generically-typed version with the object that is being stored. In the event of overlapping timeline entries, timeline intervals may be chunked. The underlying data associated with a timeline entry remains unchanged when chunking occurs. After loading objects via the add() method, the lookup(Interval) method can be used to get the list of the most recent objects (according to the version) that match the given interval. The intent is that objects represent a certain time period and when you do a lookup(), you are asking for all of the objects that you need to look at in order to get a correct answer about that time period. The findOvershadowed() method returns a list of objects that will never be returned by a call to lookup() because they are overshadowed by some other object. This can be used in conjunction with the add() and remove() methods to achieve "atomic" updates. First add new items, then check if those items caused anything to be overshadowed, if so, remove the overshadowed elements and you have effectively updated your data set without any user impact.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	VersionedIntervalTimeline.TimelineEntry

Constructor Summary

Constructors

Constructor and Description
VersionedIntervalTimeline(Comparator<? super VersionType> versionComparator)

Method Summary

Methods

Modifier and Type	Method and Description
void	add(org.joda.time.Interval interval, VersionType version, io.druid.timeline.partition.PartitionChunk<ObjectType> object)
PartitionHolder<ObjectType>	findEntry(org.joda.time.Interval interval, VersionType version)
Set<TimelineObjectHolder<VersionType,ObjectType>>	findOvershadowed()
List<TimelineObjectHolder<VersionType,ObjectType>>	lookup(org.joda.time.Interval interval) Does a lookup for the objects representing the given time interval.
io.druid.timeline.partition.PartitionChunk<ObjectType>	remove(org.joda.time.Interval interval, VersionType version, io.druid.timeline.partition.PartitionChunk<ObjectType> chunk)

Methods inherited from class java.lang.Object

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

Constructor Detail

VersionedIntervalTimeline

public VersionedIntervalTimeline(Comparator<? super VersionType> versionComparator)

Method Detail

add

public void add(org.joda.time.Interval interval,
       VersionType version,
       io.druid.timeline.partition.PartitionChunk<ObjectType> object)

remove

public io.druid.timeline.partition.PartitionChunk<ObjectType> remove(org.joda.time.Interval interval,
                                                            VersionType version,
                                                            io.druid.timeline.partition.PartitionChunk<ObjectType> chunk)

findEntry

public PartitionHolder<ObjectType> findEntry(org.joda.time.Interval interval,
                                    VersionType version)

Specified by:

findEntry in interface TimelineLookup<VersionType,ObjectType>

lookup

public List<TimelineObjectHolder<VersionType,ObjectType>> lookup(org.joda.time.Interval interval)

Does a lookup for the objects representing the given time interval. Will *only* return PartitionHolders that are complete.

Specified by:

lookup in interface TimelineLookup<VersionType,ObjectType>

Parameters:

interval - interval to find objects for

Returns:

Holders representing the interval that the objects exist for, PartitionHolders are guaranteed to be complete

findOvershadowed

public Set<TimelineObjectHolder<VersionType,ObjectType>> findOvershadowed()