org.apache.druid.segment

Interface Segment

All Superinterfaces:

AutoCloseable, Closeable

All Known Subinterfaces:

SegmentReference

All Known Implementing Classes:

AbstractSegment, HashJoinSegment, IncrementalIndexSegment, LookupSegment, QueryableIndexSegment, ReferenceCountingSegment, RowBasedSegment

public interface Segment
extends Closeable

The difference between this class and DataSegment is that DataSegment contains the segment metadata only, while this class represents the actual body of segment data, queryable.

Method Summary

Modifier and Type	Method and Description
default <T> T	as(Class<T> clazz) Request an implementation of a particular interface.
QueryableIndex	asQueryableIndex()
StorageAdapter	asStorageAdapter()
org.joda.time.Interval	getDataInterval()
SegmentId	getId()

Methods inherited from interface java.io.Closeable

close

Method Detail

getId

SegmentId getId()

getDataInterval

org.joda.time.Interval getDataInterval()

asQueryableIndex

@Nullable
QueryableIndex asQueryableIndex()

asStorageAdapter

StorageAdapter asStorageAdapter()

as

@Nullable
default <T> T as(Class<T> clazz)

Request an implementation of a particular interface. If the passed-in interface is QueryableIndex or StorageAdapter, then this method behaves identically to asQueryableIndex() or asStorageAdapter(). Other interfaces are only expected to be requested by callers that have specific knowledge of extra features provided by specific segment types. For example, an extension might provide a custom Segment type that can offer both StorageAdapter and some new interface. That extension can also offer a Query that uses that new interface. Implementations which accept classes other than QueryableIndex or StorageAdapter are limited to using those classes within the extension. This means that one extension cannot rely on the `Segment.as` behavior of another extension.

Type Parameters:

T - desired interface

Parameters:

clazz - desired interface

Returns:

instance of clazz, or null if the interface is not supported by this segment