/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.custom;

import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.events.*;

/**
 * A TableCursor provides a way for the user to navigate around a Table
 * using the keyboard.  It also provides a mechanism for selecting an
 * individual cell in a table.
 * 
 * <p> Here is an example of using a TableCursor to navigate to a cell and then edit it.
 * 
 * <code><pre>
 *  public static void main(String[] args) {
 *		Display display = new Display();
 *		Shell shell = new Shell(display);
 *		shell.setLayout(new GridLayout());
 *	
 *		// create a a table with 3 columns and fill with data
 *		final Table table = new Table(shell, SWT.BORDER | SWT.MULTI | SWT.FULL_SELECTION);
 *		table.setLayoutData(new GridData(GridData.FILL_BOTH));
 *		TableColumn column1 = new TableColumn(table, SWT.NONE);
 *		TableColumn column2 = new TableColumn(table, SWT.NONE);
 *		TableColumn column3 = new TableColumn(table, SWT.NONE);
 *		for (int i = 0; i &lt; 100; i++) {
 *			TableItem item = new TableItem(table, SWT.NONE);
 *			item.setText(new String[] { "cell "+i+" 0", "cell "+i+" 1", "cell "+i+" 2"});
 *		}
 *		column1.pack();
 *		column2.pack();
 *		column3.pack();
 *	
 *		// create a TableCursor to navigate around the table
 *		final TableCursor cursor = new TableCursor(table, SWT.NONE);
 *		// create an editor to edit the cell when the user hits "ENTER" 
 *		// while over a cell in the table
 *		final ControlEditor editor = new ControlEditor(cursor);
 *		editor.grabHorizontal = true;
 *		editor.grabVertical = true;
 *	
 *		cursor.addSelectionListener(new SelectionAdapter() {
 *			// when the TableEditor is over a cell, select the corresponding row in 
 *			// the table
 *			public void widgetSelected(SelectionEvent e) {
 *				table.setSelection(new TableItem[] {cursor.getRow()});
 *			}
 *			// when the user hits "ENTER" in the TableCursor, pop up a text editor so that 
 *			// they can change the text of the cell
 *			public void widgetDefaultSelected(SelectionEvent e){
 *				final Text text = new Text(cursor, SWT.NONE);
 *				TableItem row = cursor.getRow();
 *				int column = cursor.getColumn();
 *				text.setText(row.getText(column));
 *				text.addKeyListener(new KeyAdapter() {
 *					public void keyPressed(KeyEvent e) {
 *						// close the text editor and copy the data over 
 *						// when the user hits "ENTER"
 *						if (e.character == SWT.CR) {
 *							TableItem row = cursor.getRow();
 *							int column = cursor.getColumn();
 *							row.setText(column, text.getText());
 *							text.dispose();
 *						}
 *						// close the text editor when the user hits "ESC"
 *						if (e.character == SWT.ESC) {
 *							text.dispose();
 *						}
 *					}
 *				});
 *				editor.setEditor(text);
 *				text.setFocus();
 *			}
 *		});
 *		// Hide the TableCursor when the user hits the "MOD1" or "MOD2" key.
 *		// This allows the user to select multiple items in the table.
 *		cursor.addKeyListener(new KeyAdapter() {
 *			public void keyPressed(KeyEvent e) {
 *				if (e.keyCode == SWT.MOD1 || 
 *				    e.keyCode == SWT.MOD2 || 
 *				    (e.stateMask & SWT.MOD1) != 0 || 
 *				    (e.stateMask & SWT.MOD2) != 0) {
 *					cursor.setVisible(false);
 *				}
 *			}
 *		});
 *		// Show the TableCursor when the user releases the "MOD2" or "MOD1" key.
 *		// This signals the end of the multiple selection task.
 *		table.addKeyListener(new KeyAdapter() {
 *			public void keyReleased(KeyEvent e) {
 *				if (e.keyCode == SWT.MOD1 && (e.stateMask & SWT.MOD2) != 0) return;
 *				if (e.keyCode == SWT.MOD2 && (e.stateMask & SWT.MOD1) != 0) return;
 *				if (e.keyCode != SWT.MOD1 && (e.stateMask & SWT.MOD1) != 0) return;
 *				if (e.keyCode != SWT.MOD2 && (e.stateMask & SWT.MOD2) != 0) return;
 *			
 *				TableItem[] selection = table.getSelection();
 *				TableItem row = (selection.length == 0) ? table.getItem(table.getTopIndex()) : selection[0];
 *				table.showItem(row);
 *				cursor.setSelection(row, 0);
 *				cursor.setVisible(true);
 *				cursor.setFocus();
 *			}
 *		});
 *	
 *		shell.open();
 *		while (!shell.isDisposed()) {
 *			if (!display.readAndDispatch())
 *				display.sleep();
 *		}
 *		display.dispose();
 *	}
 * </pre></code>
 * 
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>BORDER</dd>
 * <dt><b>Events:</b></dt>
 * <dd>Selection, DefaultSelection</dd>
 * </dl>
 * 
 * @since 2.0
 *
 * @see <a href="http://www.eclipse.org/swt/snippets/#tablecursor">TableCursor snippets</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> 
 */
public class TableCursor extends Canvas {
	Table table;
	TableItem row = null;
	TableColumn column = null;
	Listener listener, tableListener, resizeListener, disposeItemListener, disposeColumnListener;

	Color background = null;
	Color foreground = null;

	// By default, invert the list selection colors
	static final int BACKGROUND = SWT.COLOR_LIST_SELECTION_TEXT;
	static final int FOREGROUND = SWT.COLOR_LIST_SELECTION;

/**
 * Constructs a new instance of this class given its parent
 * table and a style value describing its behavior and appearance.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>SWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together 
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>SWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a Table control which will be the parent of the new instance (cannot be null)
 * @param style the style of control to construct
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 *
 * @see SWT#BORDER
 * @see Widget#checkSubclass()
 * @see Widget#getStyle()
 */
public TableCursor(Table parent, int style) {
	super(parent, style);
	table = parent;
	setBackground(null);
	setForeground(null);
	
	listener = new Listener() {
		public void handleEvent(Event event) {
			switch (event.type) {
				case SWT.Dispose :
					onDispose(event);
					break;
				case SWT.FocusIn :
				case SWT.FocusOut :
					redraw();
					break;
				case SWT.KeyDown :
					keyDown(event);
					break;
				case SWT.Paint :
					paint(event);
					break;
				case SWT.Traverse : {
					event.doit = true;
					switch (event.detail) {
						case SWT.TRAVERSE_ARROW_NEXT :
						case SWT.TRAVERSE_ARROW_PREVIOUS :
						case SWT.TRAVERSE_RETURN :
							event.doit = false;
							break;
					}
					break;
				}
			}
		}
	};
	int[] events = new int[] {SWT.Dispose, SWT.FocusIn, SWT.FocusOut, SWT.KeyDown, SWT.Paint, SWT.Traverse};
	for (int i = 0; i < events.length; i++) {
		addListener(events[i], listener);
	}

	tableListener = new Listener() {
		public void handleEvent(Event event) {
			switch (event.type) {
				case SWT.MouseDown :
					tableMouseDown(event);
					break;
				case SWT.FocusIn :
					tableFocusIn(event);
					break;
			}
		}
	};
	table.addListener(SWT.FocusIn, tableListener);
	table.addListener(SWT.MouseDown, tableListener);

	disposeItemListener = new Listener() {
		public void handleEvent(Event event) {
			unhookRowColumnListeners();
			row = null;
			column = null;
			_resize();
		}
	};
	disposeColumnListener = new Listener() {
		public void handleEvent(Event event) {
			unhookRowColumnListeners();
			row = null;
			column = null;
			_resize();
		}
	};
	resizeListener = new Listener() {
		public void handleEvent(Event event) {
			_resize();
		}
	};
	ScrollBar hBar = table.getHorizontalBar();
	if (hBar != null) {
		hBar.addListener(SWT.Selection, resizeListener);
	}
	ScrollBar vBar = table.getVerticalBar();
	if (vBar != null) {
		vBar.addListener(SWT.Selection, resizeListener);
	}
}

/**
 * Adds the listener to the collection of listeners who will
 * be notified when the user changes the receiver's selection, by sending
 * it one of the messages defined in the <code>SelectionListener</code>
 * interface.
 * <p>
 * When <code>widgetSelected</code> is called, the item field of the event object is valid.
 * If the receiver has <code>SWT.CHECK</code> style set and the check selection changes,
 * the event object detail field contains the value <code>SWT.CHECK</code>.
 * <code>widgetDefaultSelected</code> is typically called when an item is double-clicked.
 * </p>
 *
 * @param listener the listener which should be notified when the user changes the receiver's selection
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see SelectionListener
 * @see SelectionEvent
 * @see #removeSelectionListener(SelectionListener)
 * 
 */
public void addSelectionListener(SelectionListener listener) {
	checkWidget();
	if (listener == null)
		SWT.error(SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener(listener);
	addListener(SWT.Selection, typedListener);
	addListener(SWT.DefaultSelection, typedListener);
}

void onDispose(Event event) {
	removeListener(SWT.Dispose, listener);
	notifyListeners(SWT.Dispose, event);
	event.type = SWT.None;

	table.removeListener(SWT.FocusIn, tableListener);
	table.removeListener(SWT.MouseDown, tableListener);
	unhookRowColumnListeners();
	ScrollBar hBar = table.getHorizontalBar();
	if (hBar != null) {
		hBar.removeListener(SWT.Selection, resizeListener);
	}
	ScrollBar vBar = table.getVerticalBar();
	if (vBar != null) {
		vBar.removeListener(SWT.Selection, resizeListener);
	}
}

void keyDown(Event event) {
	if (row == null) return;
	switch (event.character) {
		case SWT.CR :
			notifyListeners(SWT.DefaultSelection, new Event());
			return;
	}
	int rowIndex = table.indexOf(row);
	int columnIndex = column == null ? 0 : table.indexOf(column);
	switch (event.keyCode) {
		case SWT.ARROW_UP :
			setRowColumn(Math.max(0, rowIndex - 1), columnIndex, true);
			break;
		case SWT.ARROW_DOWN :
			setRowColumn(Math.min(rowIndex + 1, table.getItemCount() - 1), columnIndex, true);
			break;
        case SWT.ARROW_LEFT :
        case SWT.ARROW_RIGHT :
        	{	
        		int columnCount = table.getColumnCount();
        		if (columnCount == 0) break;
        		int[] order = table.getColumnOrder();
        		int index = 0;
        		while (index < order.length) {
        			if (order[index] == columnIndex) break;
        			index++;
				}
				if (index == order.length) index = 0;
		        int leadKey = (getStyle() & SWT.RIGHT_TO_LEFT) != 0 ? SWT.ARROW_RIGHT : SWT.ARROW_LEFT;
		        if (event.keyCode == leadKey) {
		           setRowColumn(rowIndex, order[Math.max(0, index - 1)], true);
		        } else {
		           setRowColumn(rowIndex, order[Math.min(columnCount - 1, index + 1)], true);
		        }
		        break;
        	}
		case SWT.HOME :
			setRowColumn(0, columnIndex, true);
			break;
		case SWT.END :
			{
				int i = table.getItemCount() - 1;
				setRowColumn(i, columnIndex, true);
				break;
			}
		case SWT.PAGE_UP :
			{
				int index = table.getTopIndex();
				if (index == rowIndex) {
					Rectangle rect = table.getClientArea();
					TableItem item = table.getItem(index);
					Rectangle itemRect = item.getBounds(0);
					rect.height -= itemRect.y;
					int height = table.getItemHeight();
					int page = Math.max(1, rect.height / height);
					index = Math.max(0, index - page + 1);
				}
				setRowColumn(index, columnIndex, true);
				break;
			}
		case SWT.PAGE_DOWN :
			{
				int index = table.getTopIndex();
				Rectangle rect = table.getClientArea();
				TableItem item = table.getItem(index);
				Rectangle itemRect = item.getBounds(0);
				rect.height -= itemRect.y;
				int height = table.getItemHeight();
				int page = Math.max(1, rect.height / height);
				int end = table.getItemCount() - 1;
				index = Math.min(end, index + page - 1);
				if (index == rowIndex) {
					index = Math.min(end, index + page - 1);
				}
				setRowColumn(index, columnIndex, true);
				break;
			}
	}
}

void paint(Event event) {
	if (row == null) return;
	int columnIndex = column == null ? 0 : table.indexOf(column);
	GC gc = event.gc;
	Display display = getDisplay();
	gc.setBackground(getBackground());
	gc.setForeground(getForeground());
	gc.fillRectangle(event.x, event.y, event.width, event.height);
	int x = 0;
	Point size = getSize();
	Image image = row.getImage(columnIndex);
	if (image != null) {
		Rectangle imageSize = image.getBounds();
		int imageY = (size.y - imageSize.height) / 2;
		gc.drawImage(image, x, imageY);
		x += imageSize.width;
	}
	String text = row.getText(columnIndex);
	if (text.length() > 0) {
		Rectangle bounds = row.getBounds(columnIndex);
		Point extent = gc.stringExtent(text);
		// Temporary code - need a better way to determine table trim
		String platform = SWT.getPlatform();
		if ("win32".equals(platform)) { //$NON-NLS-1$
			if (table.getColumnCount() == 0 || columnIndex == 0) {
				x += 2; 
			} else {
				int alignmnent = column.getAlignment();
				switch (alignmnent) {
					case SWT.LEFT:
						x += 6;
						break;
					case SWT.RIGHT:
						x = bounds.width - extent.x - 6;
						break;
					case SWT.CENTER:
						x += (bounds.width - x - extent.x) / 2;
						break;
				}
			}
		}  else {
			if (table.getColumnCount() == 0) {
				x += 5; 
			} else {
				int alignmnent = column.getAlignment();
				switch (alignmnent) {
					case SWT.LEFT:
						x += 5;
						break;
					case SWT.RIGHT:
						x = bounds.width- extent.x - 2;
						break;
					case SWT.CENTER:
						x += (bounds.width - x - extent.x) / 2 + 2;
						break;
				}
			}
		}
		int textY = (size.y - extent.y) / 2;
		gc.drawString(text, x, textY);
	}
	if (isFocusControl()) {
		gc.setBackground(display.getSystemColor(SWT.COLOR_BLACK));
		gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
		gc.drawFocus(0, 0, size.x, size.y);
	}
}

void tableFocusIn(Event event) {
	if (isDisposed()) return;
	if (isVisible()) {
		if (row == null && column == null) return;
		setFocus();
	}
}

void tableMouseDown(Event event) {
	if (isDisposed() || !isVisible()) return;
	Point pt = new Point(event.x, event.y);
	int lineWidth = table.getLinesVisible() ? table.getGridLineWidth() : 0;
	TableItem item = table.getItem(pt);
	if ((table.getStyle() & SWT.FULL_SELECTION) != 0) {
		if (item == null) return;
	} else {
		int start = item != null ? table.indexOf(item) : table.getTopIndex();
		int end = table.getItemCount();
		Rectangle clientRect = table.getClientArea();
		for (int i = start; i < end; i++) {
			TableItem nextItem = table.getItem(i);
			Rectangle rect = nextItem.getBounds(0);
			if (pt.y >= rect.y && pt.y < rect.y + rect.height + lineWidth) {
				item = nextItem;
				break;
			}
			if (rect.y > clientRect.y + clientRect.height) 	return;
		}
		if (item == null) return;
	}
	TableColumn newColumn = null;
	int columnCount = table.getColumnCount();
	if (columnCount == 0) {
		if ((table.getStyle() & SWT.FULL_SELECTION) == 0) {
			Rectangle rect = item.getBounds(0);
			rect.width += lineWidth;
			rect.height += lineWidth;
			if (!rect.contains(pt)) return;
		}
	} else {
		for (int i = 0; i < columnCount; i++) {
			Rectangle rect = item.getBounds(i);
			rect.width += lineWidth;
			rect.height += lineWidth;
			if (rect.contains(pt)) {
				newColumn = table.getColumn(i);
				break;
			}
		}
		if (newColumn == null) {
			if ((table.getStyle() & SWT.FULL_SELECTION) == 0) return;
			newColumn = table.getColumn(0);
		}
	}
	setRowColumn(item, newColumn, true);
	setFocus();
	return;
}
void setRowColumn(int row, int column, boolean notify) {
	TableItem item = row == -1 ? null : table.getItem(row);
	TableColumn col = column == -1 || table.getColumnCount() == 0 ? null : table.getColumn(column);
	setRowColumn(item, col, notify);
}
void setRowColumn(TableItem row, TableColumn column, boolean notify) {
	if (this.row == row && this.column == column) {
		return;
	}
	if (this.row != null && this.row != row) {
		this.row.removeListener(SWT.Dispose, disposeItemListener);
		this.row = null;
	}
	if (this.column != null && this.column != column) {
		this.column.removeListener(SWT.Dispose, disposeColumnListener);
		this.column.removeListener(SWT.Move, resizeListener);
		this.column.removeListener(SWT.Resize, resizeListener);
		this.column = null;
	}
	if (row != null) {
		if (this.row != row) {
			this.row = row;
			row.addListener(SWT.Dispose, disposeItemListener);
			table.showItem(row);
		}
		if (this.column != column && column != null) {
			this.column = column;
			column.addListener(SWT.Dispose, disposeColumnListener);
			column.addListener(SWT.Move, resizeListener);
			column.addListener(SWT.Resize, resizeListener);
			table.showColumn(column);
		}
		int columnIndex = column == null ? 0 : table.indexOf(column);
		setBounds(row.getBounds(columnIndex));
		redraw();
		if (notify) {
			notifyListeners(SWT.Selection, new Event());
		}
	}
}

public void setVisible(boolean visible) {
	checkWidget();
	if (visible) _resize();
	super.setVisible(visible);
}

/**
 * Removes the listener from the collection of listeners who will
 * be notified when the user changes the receiver's selection.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see SelectionListener
 * @see #addSelectionListener(SelectionListener)
 * 
 * @since 3.0
 */
public void removeSelectionListener(SelectionListener listener) {
	checkWidget();
	if (listener == null) {
		SWT.error(SWT.ERROR_NULL_ARGUMENT);
	}
	removeListener(SWT.Selection, listener);
	removeListener(SWT.DefaultSelection, listener);	
}

void _resize() {
	if (row == null) {
		setBounds(-200, -200, 0, 0);
	} else {
		int columnIndex = column == null ? 0 : table.indexOf(column);
		setBounds(row.getBounds(columnIndex));
	}
}
/**
 * Returns the column over which the TableCursor is positioned.
 *
 * @return the column for the current position
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getColumn() {
	checkWidget();
	return column == null ? 0 : table.indexOf(column);
}
/**
 * Returns the background color that the receiver will use to draw.
 *
 * @return the receiver's background color
 */
public Color getBackground() {
	checkWidget();
	if (background == null) {
		return getDisplay().getSystemColor(BACKGROUND);
	}
	return background;
}
/**
 * Returns the foreground color that the receiver will use to draw.
 *
 * @return the receiver's foreground color
 */
public Color getForeground() {
	checkWidget();
	if (foreground == null) {
		return getDisplay().getSystemColor(FOREGROUND);
	}
	return foreground;
}
/**
 * Returns the row over which the TableCursor is positioned.
 *
 * @return the item for the current position
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public TableItem getRow() {
	checkWidget();
	return row;
}
/**
 * Sets the receiver's background color to the color specified
 * by the argument, or to the default system color for the control
 * if the argument is null.
 * <p>
 * Note: This operation is a hint and may be overridden by the platform.
 * For example, on Windows the background of a Button cannot be changed.
 * </p>
 * @param color the new color (or null)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the argument has been disposed</li> 
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setBackground (Color color) {
	background = color;
	super.setBackground(getBackground());
	redraw();
}
/**
 * Sets the receiver's foreground color to the color specified
 * by the argument, or to the default system color for the control
 * if the argument is null.
 * <p>
 * Note: This operation is a hint and may be overridden by the platform.
 * </p>
 * @param color the new color (or null)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the argument has been disposed</li> 
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setForeground (Color color) {
	foreground = color;
	super.setForeground(getForeground());
	redraw();
}
/**
 * Positions the TableCursor over the cell at the given row and column in the parent table. 
 *
 * @param row the index of the row for the cell to select
 * @param column the index of column for the cell to select
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 */
public void setSelection(int row, int column) {
	checkWidget();
	int columnCount = table.getColumnCount();
	int maxColumnIndex =  columnCount == 0 ? 0 : columnCount - 1;
	if (row < 0
	    || row >= table.getItemCount()
		|| column < 0
		|| column > maxColumnIndex)
		SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	setRowColumn(row, column, false);
}
/**
 * Positions the TableCursor over the cell at the given row and column in the parent table. 
 *
 * @param row the TableItem of the row for the cell to select
 * @param column the index of column for the cell to select
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 */
public void setSelection(TableItem row, int column) {
	checkWidget();
	int columnCount = table.getColumnCount();
	int maxColumnIndex =  columnCount == 0 ? 0 : columnCount - 1;
	if (row == null
		|| row.isDisposed()
		|| column < 0
		|| column > maxColumnIndex)
		SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	setRowColumn(table.indexOf(row), column, false);
}
void unhookRowColumnListeners() {
	if (column != null) {
		column.removeListener(SWT.Dispose, disposeColumnListener);
		column.removeListener(SWT.Move, resizeListener);
		column.removeListener(SWT.Resize, resizeListener);
		column = null;
	}
	if (row != null) {
		row.removeListener(SWT.Dispose, disposeItemListener);
		row = null;
	}
}
}
