Package org.apache.druid.frame.segment

Class FrameCursor

java.lang.Object

org.apache.druid.frame.segment.FrameCursor

All Implemented Interfaces:

Cursor

public class FrameCursor
extends Object
implements Cursor

An implementation of Cursor used by RowFrameCursorFactory and ColumnarFrameCursorFactory. Adds the methods getCurrentRow() and setCurrentRow(int) so the cursor can be moved to particular rows.

Constructor Summary

Constructors

Constructor	Description
FrameCursor(SimpleSettableOffset offset, ColumnSelectorFactory columnSelectorFactory)

Method Summary

Modifier and Type	Method	Description
void	advance()	Advance the cursor to the next position, checking if thread has been interrupted after advancing and possibly throwing QueryInterruptedException if so.
void	advanceUninterruptibly()	Advance to the cursor to the next position.
ColumnSelectorFactory	getColumnSelectorFactory()	Get a ColumnSelectorFactory whose selectors will be backed by the row values at the current position of the cursor
int	getCurrentRow()	Returns the current row number.
boolean	isDone()	Check if the current cursor position is valid, returning false if there are values to read from selectors created by Cursor.getColumnSelectorFactory().
boolean	isDoneOrInterrupted()	Check if the current cursor position is valid, or if the thread has been interrupted.
void	reset()	Reset to start of cursor.
void	setCurrentRow(int rowNumber)	Moves this cursor to a particular row number.

Methods inherited from class java.lang.Object

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

Constructor Details

FrameCursor

public FrameCursor(SimpleSettableOffset offset,
 ColumnSelectorFactory columnSelectorFactory)

Method Details

getColumnSelectorFactory

public ColumnSelectorFactory getColumnSelectorFactory()

Description copied from interface: Cursor

Get a ColumnSelectorFactory whose selectors will be backed by the row values at the current position of the cursor

Specified by:

getColumnSelectorFactory in interface Cursor

advance

public void advance()

Description copied from interface: Cursor

Advance the cursor to the next position, checking if thread has been interrupted after advancing and possibly throwing QueryInterruptedException if so. Callers should check Cursor.isDone() or Cursor.isDoneOrInterrupted() before getting the next value from a selector.

Specified by:

advance in interface Cursor

advanceUninterruptibly

public void advanceUninterruptibly()

Description copied from interface: Cursor

Advance to the cursor to the next position. Callers should check Cursor.isDone() or Cursor.isDoneOrInterrupted() before getting the next value from a selector. However, underlying implementation may still check for thread interruption if advancing the cursor is a long-running operation.

Specified by:

advanceUninterruptibly in interface Cursor

isDone

public boolean isDone()

Description copied from interface: Cursor

Check if the current cursor position is valid, returning false if there are values to read from selectors created by Cursor.getColumnSelectorFactory(). If true, any such selectors will no longer produce values.

Specified by:

isDone in interface Cursor

isDoneOrInterrupted

public boolean isDoneOrInterrupted()

Description copied from interface: Cursor

Check if the current cursor position is valid, or if the thread has been interrupted.

Specified by:

isDoneOrInterrupted in interface Cursor

See Also:

• Cursor.isDone()

reset

public void reset()

Description copied from interface: Cursor

Reset to start of cursor. Most cursor implementations are backed by immutable data, but there is generically no guarantee that advancing through a cursor again will read exactly the same data or even number of rows, since the underlying data might be mutable in some cases.

Specified by:

reset in interface Cursor

getCurrentRow

public int getCurrentRow()

Returns the current row number.

setCurrentRow

public void setCurrentRow(int rowNumber)

Moves this cursor to a particular row number.