Class ColumnarIterator

java.lang.Object

com.oracle.labs.mlrg.olcut.util.IOSpliterator<ColumnarIterator.Row>

org.tribuo.data.columnar.ColumnarIterator

All Implemented Interfaces:

Iterator<ColumnarIterator.Row>, Spliterator<ColumnarIterator.Row>

Direct Known Subclasses:

CSVIterator, JsonFileIterator, ResultSetIterator

public abstract class ColumnarIterator
extends com.oracle.labs.mlrg.olcut.util.IOSpliterator<ColumnarIterator.Row>
implements Iterator<ColumnarIterator.Row>

An abstract class for iterators that read data in to a columnar format, usually from a file of some kind. Subclasses handle how to format data from that file.

Note: the fields field must be set in the constructor of implementing classes.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ColumnarIterator.Row	A representation of a row of untyped data from a columnar data source.

Nested classes/interfaces inherited from interface java.util.Spliterator

Spliterator.OfDouble, Spliterator.OfInt, Spliterator.OfLong, Spliterator.OfPrimitive<T, T_CONS, T_SPLITR extends Spliterator.OfPrimitive<T,T_CONS,T_SPLITR>>

Field Summary

Fields

Modifier and Type	Field	Description
protected Optional<ColumnarIterator.Row>	currentRow	The current row.
protected List<String>	fields	The column headers for this iterator.

Fields inherited from class com.oracle.labs.mlrg.olcut.util.IOSpliterator

DEFAULT_BATCH_SIZE, DEFAULT_CHARACTERISTICS

Fields inherited from interface java.util.Spliterator

CONCURRENT, DISTINCT, IMMUTABLE, NONNULL, ORDERED, SIZED, SORTED, SUBSIZED

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ColumnarIterator()	Constructs a ColumnarIterator wrapped around a buffering spliterator.
protected	ColumnarIterator(int characteristics, int batchsize, long estimatedSize)	Constructs a ColumnarIterator wrapped around a buffering spliterator.

Method Summary

Modifier and Type	Method	Description
void	forEachRemaining(Consumer<? super ColumnarIterator.Row> action)
List<String>	getFields()	The immutable list of field names.
protected abstract Optional<ColumnarIterator.Row>	getRow()	Returns the next row of data based on internal state stored by the implementor, or Optional.empty() if there is no more data.
boolean	hasNext()
ColumnarIterator.Row	next()
boolean	tryAdvance(Consumer<? super ColumnarIterator.Row> action)

Methods inherited from class com.oracle.labs.mlrg.olcut.util.IOSpliterator

characteristics, estimateSize, trySplit

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

remove

Methods inherited from interface java.util.Spliterator

getComparator, getExactSizeIfKnown, hasCharacteristics

Field Details

fields

protected List<String> fields

The column headers for this iterator.

currentRow

protected Optional<ColumnarIterator.Row> currentRow

The current row.

Constructor Details

ColumnarIterator

protected ColumnarIterator()

Constructs a ColumnarIterator wrapped around a buffering spliterator.

Note when using this constructor you must set the fields field to the appropriate value after you've called super(). It must be immutable.

ColumnarIterator

protected ColumnarIterator(int characteristics,
 int batchsize,
 long estimatedSize)

Constructs a ColumnarIterator wrapped around a buffering spliterator.

Note when using this constructor you must set the fields field to the appropriate value after you've called super(). It must be immutable.

Parameters:

characteristics - The spliterator characteristics.

batchsize - The buffer size.

estimatedSize - The estimated size of this iterator.

Method Details

getFields

public List<String> getFields()

The immutable list of field names.

Returns:

The field names.

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<ColumnarIterator.Row>

next

public ColumnarIterator.Row next()

Specified by:

next in interface Iterator<ColumnarIterator.Row>

tryAdvance

public boolean tryAdvance(Consumer<? super ColumnarIterator.Row> action)

Specified by:

tryAdvance in interface Spliterator<ColumnarIterator.Row>

forEachRemaining

public void forEachRemaining(Consumer<? super ColumnarIterator.Row> action)

Specified by:

forEachRemaining in interface Iterator<ColumnarIterator.Row>

Specified by:

forEachRemaining in interface Spliterator<ColumnarIterator.Row>

getRow

protected abstract Optional<ColumnarIterator.Row> getRow()

Returns the next row of data based on internal state stored by the implementor, or Optional.empty() if there is no more data.

Returns:

The next row of data or None.