org.knime.core.data
Class RowIterator

java.lang.Object
  org.knime.core.data.RowIterator

All Implemented Interfaces:

Iterator<DataRow>

Direct Known Subclasses:

AffineTransRowIterator, AppendedColumnRowIterator, AppendedRowsIterator, ARFFRowIterator, BasisFunctionIterator, BasisFunctionPredictorRowIterator, CloseableRowIterator, DefaultRowIterator, FileReaderPreviewRowIterator, FileRowIterator, FilterColumnRowIterator, FilterRowIterator, InMemoryIterator, JoinedTableRowIterator, MissingValueHandling2TableIterator, ReplacedColumnsRowIterator, RowFilterIterator

public abstract class RowIterator
extends Object
implements Iterator<DataRow>

Classes extending this class iterate over the rows of a DataTable. Each DataTable has its specific RowIterator, which returns the rows one by one. A RowIterator must return the rows always in the same order.

Use RowIterators as follows:

     DataTable table = ...;
     for (RowIterator it = table.getRowIterator(); it.hasNext();) {
         DataRow row = it.next();
         ...
     }
 

or, if you don't need access to the iterator:

     DataTable table =...;
     for (DataRow row : table) {
       // access the row here
     }
 

Note, the difference of this class to a generic Iterator<DataRow> is that it does not allow to remove elements.

Author:

Thomas Gabriel, University of Konstanz

See Also:

DataRow

Constructor Summary

RowIterator()

Method Summary

abstract boolean	hasNext() Returns true if there are more rows and false otherwise.
abstract DataRow	next() Returns the next DataRow.
void	remove() NOT supported by the DataTable iterator! DataTables are immutable read-only objects after their creation.

Methods inherited from class java.lang.Object

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

Constructor Detail

RowIterator

public RowIterator()

Method Detail

hasNext

public abstract boolean hasNext()

Returns true if there are more rows and false otherwise.

Specified by:

hasNext in interface Iterator<DataRow>

Returns:

true if the iterator has more elements, otherwise false

See Also:

next()

next

public abstract DataRow next()

Returns the next DataRow.

Specified by:

next in interface Iterator<DataRow>

Returns:

the next row in the DataTable

Throws:

NoSuchElementException - if there are no more rows

remove

public final void remove()

NOT supported by the DataTable iterator! DataTables are immutable read-only objects after their creation. Do not call this method, it will throw an exception.

Specified by:

remove in interface Iterator<DataRow>

Throws:

UnsupportedOperationException - if the remove operation is not supported by this Iterator.