uk.ac.starlink.table.gui

Class ViewHugeTableModel

java.lang.Object

uk.ac.starlink.table.gui.ViewHugeTableModel

All Implemented Interfaces:

javax.swing.table.TableModel

public class ViewHugeTableModel
extends java.lang.Object
implements javax.swing.table.TableModel

Swing TableModel implementation which provides a view on a very large table model.

The point of this is for displaying tables with very large row counts in a JTable. Since the default height of a JTable row is 16 pixels (see JTable.getRowHeight()) a JTable component with more than 2^27 rows (about 134 million) will have a height in pixels which is too large to represent in a 32-bit int. In that case Swing gives up and just doesn't display the thing.

This class implements a model of a fixed (large but not too large) size, VIEWSIZE rows, which at any one time gives a view of a contiguous sequence of rows from the base table, starting at a mutable value given by getViewBase(). It works out the value of viewBase by reference to a scrollbar which is owned by this model, and assumed to control vertical scrolling of the scroll panel displaying the JTable that views it. The viewBase value is updated dynamically according to the current state (position) of the scrollbar. Whenever the viewBase changes, listeners (most importantly the client JTable) are notified.

In principle, every time the scrollbar position, or equivalently the set of currently visible rows, changes, the viewBase should change. But since the scrollbar has only pixel resolution, smallish changes can be accommodated without needing to take the somewhat expensive step of changing the viewBase.

The underlying table model can still only have up to 2^31 rows. The general approach used here would work for larger underlying row data, but it would be necessary to define a new long-capable TableModel interface to accommodate such data.

It is not recommended to use this class for underlying table models which are not in fact huge.

Note this class will only help you for displaying a JTable within a scrollpane. If you want to display a giga-row JTable unscrolled on a 100km tall VDU, you're on your own.

Since:

16 Jul 2014

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	VIEWBASE_PROPERTY Name of property giving underlying value of first row of this model.
static int	VIEWSIZE Fixed number of rows displayed by this model.

Constructor Summary

Constructors

Constructor and Description
ViewHugeTableModel() Constructs an empty model.
ViewHugeTableModel(javax.swing.table.TableModel hugeModel, javax.swing.JScrollBar vbar) Constructs a configured model.

Method Summary

Modifier and Type	Method and Description
void	addPropertyChangeListener(java.beans.PropertyChangeListener lnr) Adds a listener that will be notified about ViewBase changes.
void	addTableModelListener(javax.swing.event.TableModelListener lnr)
void	configureModel(javax.swing.table.TableModel hugeModel, javax.swing.JScrollBar vbar) Sets this mode up for use with a given underlying table model and scroll bar.
protected void	firePropertyChanged(java.beans.PropertyChangeEvent evt) Notifies property change listeners of a property change.
protected void	fireTableChanged(javax.swing.event.TableModelEvent evt) Notifies table model listeners of a table model event.
java.lang.Class<?>	getColumnClass(int icol)
int	getColumnCount()
java.lang.String	getColumnName(int icol)
int	getHugeRow(int iViewRow) Returns the row in the underlying huge model corresponding to a given row in this view.
int	getRowCount()
java.lang.Object	getValueAt(int irow, int icol)
int	getViewBase() Returns the offset from which this view views the underlying table model.
boolean	isCellEditable(int irow, int icol)
void	removePropertyChangeListener(java.beans.PropertyChangeListener lnr) Removes a listener added earlier.
void	removeTableModelListener(javax.swing.event.TableModelListener lnr)
void	setValueAt(java.lang.Object value, int irow, int icol)

Methods inherited from class java.lang.Object

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

Field Detail

VIEWBASE_PROPERTY

public static final java.lang.String VIEWBASE_PROPERTY

Name of property giving underlying value of first row of this model.

See Also:

Constant Field Values

VIEWSIZE

public static final int VIEWSIZE

Fixed number of rows displayed by this model.

See Also:

Constant Field Values

Constructor Detail

ViewHugeTableModel

public ViewHugeTableModel()

Constructs an empty model.

ViewHugeTableModel

public ViewHugeTableModel(javax.swing.table.TableModel hugeModel,
                          javax.swing.JScrollBar vbar)

Constructs a configured model.

Parameters:

hugeModel - table model with more than VIEWSIZE rows

vbar - scrollbar used to control vertical scrolling of table view

Method Detail

configureModel

public void configureModel(javax.swing.table.TableModel hugeModel,
                           javax.swing.JScrollBar vbar)

Sets this mode up for use with a given underlying table model and scroll bar.

Parameters:

hugeModel - table model with more than VIEWSIZE rows

vbar - scrollbar used to control vertical scrolling of table view

getRowCount

public int getRowCount()

Specified by:

getRowCount in interface javax.swing.table.TableModel

getValueAt

public java.lang.Object getValueAt(int irow,
                                   int icol)

Specified by:

getValueAt in interface javax.swing.table.TableModel

setValueAt

public void setValueAt(java.lang.Object value,
                       int irow,
                       int icol)

Specified by:

setValueAt in interface javax.swing.table.TableModel

isCellEditable

public boolean isCellEditable(int irow,
                              int icol)

Specified by:

isCellEditable in interface javax.swing.table.TableModel

getColumnCount

public int getColumnCount()

Specified by:

getColumnCount in interface javax.swing.table.TableModel

getColumnName

public java.lang.String getColumnName(int icol)

Specified by:

getColumnName in interface javax.swing.table.TableModel

getColumnClass

public java.lang.Class<?> getColumnClass(int icol)

Specified by:

getColumnClass in interface javax.swing.table.TableModel

addTableModelListener

public void addTableModelListener(javax.swing.event.TableModelListener lnr)

Specified by:

addTableModelListener in interface javax.swing.table.TableModel

removeTableModelListener

public void removeTableModelListener(javax.swing.event.TableModelListener lnr)

Specified by:

removeTableModelListener in interface javax.swing.table.TableModel

getViewBase

public int getViewBase()

Returns the offset from which this view views the underlying table model. Changes in this value will be notified to registered PropertyChangeListeners.

Returns:

view base

addPropertyChangeListener

public void addPropertyChangeListener(java.beans.PropertyChangeListener lnr)

Adds a listener that will be notified about ViewBase changes. These have the property name VIEWBASE_PROPERTY.

Parameters:

lnr - listener to add

removePropertyChangeListener

public void removePropertyChangeListener(java.beans.PropertyChangeListener lnr)

Removes a listener added earlier.

Parameters:

lnr - listener to remove

fireTableChanged

protected void fireTableChanged(javax.swing.event.TableModelEvent evt)

Notifies table model listeners of a table model event.

Parameters:

evt - event

firePropertyChanged

protected void firePropertyChanged(java.beans.PropertyChangeEvent evt)

Notifies property change listeners of a property change.

Parameters:

evt - event

getHugeRow

public int getHugeRow(int iViewRow)

Returns the row in the underlying huge model corresponding to a given row in this view.

Returns:

iViewRow + viewBase