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

Class RecordMapperWrapperRecordIterator<I,O>

java.lang.Object

org.apache.flink.connector.file.src.util.RecordMapperWrapperRecordIterator<I,O>

Type Parameters:

I - Input type

O - Mapped output type

All Implemented Interfaces:

BulkFormat.RecordIterator<O>

public class RecordMapperWrapperRecordIterator<I,O>
extends Object
implements BulkFormat.RecordIterator<O>

Implementation of BulkFormat.RecordIterator that wraps another iterator and performs the mapping of the records. You can use wrapReader(BulkFormat.Reader, RecordMapper) to wrap a whole reader.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	RecordMapperWrapperRecordIterator.RecordMapper<I,O> Record mapper definition.

Constructor Summary

Constructors

Constructor and Description
RecordMapperWrapperRecordIterator(BulkFormat.RecordIterator<I> wrapped, RecordMapperWrapperRecordIterator.RecordMapper<I,O> mapper)

Method Summary

Modifier and Type	Method and Description
RecordAndPosition<O>	next() Gets the next record from the file, together with its position.
void	releaseBatch() Releases the batch that this iterator iterated over.
static <I,O> BulkFormat.Reader<O>	wrapReader(BulkFormat.Reader<I> wrappedReader, RecordMapperWrapperRecordIterator.RecordMapper<I,O> recordMapper) Wrap a BulkFormat.Reader applying a RecordMapperWrapperRecordIterator.RecordMapper on the returned iterator.

Methods inherited from class java.lang.Object

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

Constructor Detail

RecordMapperWrapperRecordIterator

public RecordMapperWrapperRecordIterator(BulkFormat.RecordIterator<I> wrapped,
                                         RecordMapperWrapperRecordIterator.RecordMapper<I,O> mapper)

Method Detail

next

public RecordAndPosition<O> 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<O>

releaseBatch

public void releaseBatch()

Description copied from interface: BulkFormat.RecordIterator

Releases the batch that this iterator iterated over. This is not supposed to close the reader and its resources, but is simply a signal that this iterator is no used any more. This method can be used as a hook to recycle/reuse heavyweight object structures.

Specified by:

releaseBatch in interface BulkFormat.RecordIterator<O>

wrapReader

public static <I,O> BulkFormat.Reader<O> wrapReader(BulkFormat.Reader<I> wrappedReader,
                                                    RecordMapperWrapperRecordIterator.RecordMapper<I,O> recordMapper)

Wrap a BulkFormat.Reader applying a RecordMapperWrapperRecordIterator.RecordMapper on the returned iterator.

Type Parameters:

I - Input type

O - Mapped output type