Package org.apache.flink.connector.file.src.util

Class SingletonResultIterator<E>

java.lang.Object

org.apache.flink.connector.file.src.util.RecyclableIterator<E>

org.apache.flink.connector.file.src.util.SingletonResultIterator<E>

Type Parameters:

E - The type of the record returned by the iterator.

All Implemented Interfaces:

BulkFormat.RecordIterator<E>

@PublicEvolving
public final class SingletonResultIterator<E>
extends RecyclableIterator<E>
implements BulkFormat.RecordIterator<E>

A simple BulkFormat.RecordIterator that returns a single value. The iterator is mutable to support object reuse and supports recycling.

Constructor Summary

Constructors

Constructor	Description
SingletonResultIterator()
SingletonResultIterator(Runnable recycler)

Method Summary

Modifier and Type	Method	Description
RecordAndPosition<E>	next()	Gets the next record from the file, together with its position.
void	set(E element, long offset, long skipCount)	Sets the single record to be returned by this iterator.

Methods inherited from class org.apache.flink.connector.file.src.util.RecyclableIterator

releaseBatch

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.flink.connector.file.src.reader.BulkFormat.RecordIterator

releaseBatch

Constructor Details

SingletonResultIterator

public SingletonResultIterator()

SingletonResultIterator

public SingletonResultIterator(@Nullable
 Runnable recycler)

Method Details

set

public void set(E element,
 long offset,
 long skipCount)

Sets the single record to be returned by this iterator. The offset and records-to-skip count will be used as provided here for the returned RecordAndPosition, meaning they need to point to AFTER this specific record (because a checkpoint taken after the record was processed needs to resume from after this record).

next

@Nullable
public RecordAndPosition<E> next()

Description copied from interface: BulkFormat.RecordIterator

Gets the next record from the file, together with its position.

The position information returned with the record point to the record AFTER the returned record, because it defines the point where the reading should resume once the current record is emitted. The position information is put in the source's state when the record is emitted. If a checkpoint is taken directly after the record is emitted, the checkpoint must to describe where to resume the source reading from after that record.

Objects returned by this method may be reused by the iterator. By the time that this method is called again, no object returned from the previous call will be referenced any more. That makes it possible to have a single MutableRecordAndPosition object and return the same instance (with updated record and position) on every call.

Specified by:

next in interface BulkFormat.RecordIterator<E>