TableColumnManager.java

import java.awt.*;
import java.beans.*;
import java.util.ArrayList;
import java.util.List;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.*;

/**
 *  The TableColumnManager can be used to manage TableColumns. It will give the
 *  user the ability to hide columns and then reshow them in their last viewed
 *  position. This functionality is supported by a popup menu added to the
 *  table header of the table. The TableColumnModel is still used to control
 *  the view for the table. The manager will inovoke the appropriate methods
 *  of the TableColumnModel to hide/show columns as required.
 *
 */
public class TableColumnManager
	implements MouseListener, ActionListener, TableColumnModelListener, PropertyChangeListener
{
	private JTable table;
	private TableColumnModel tcm;
	private boolean menuPopup;

	private List<TableColumn> allColumns;

	/**
	 *  Convenience constructor for creating a TableColumnManager for a table.
	 *  Support for a popup menu on the table header will be enabled.
	 *
	 *  @param table the table whose TableColumns will managed.
	 */
	public TableColumnManager(JTable table)
	{
		this(table, true);
	}

	/**
	 *  Create a TableColumnManager for a table.
	 *
	 *  @param table the table whose TableColumns will managed.
	 *  @param menuPopup enable or disable a popup menu to allow the users to
	 *				   manager the visibility of TableColumns.
	 */
	public TableColumnManager(JTable table, boolean menuPopup)
	{
		this.table = table;
		setMenuPopup( menuPopup );

		table.addPropertyChangeListener( this );
		reset();
	}

	/**
	 *  Reset the TableColumnManager to only manage the TableColumns that are
	 *  currently visible in the table.
	 *
	 *  Generally this method should only be invoked by the TableColumnManager
	 *  when the TableModel of the table is changed.
	 */
	public void reset()
	{
		table.getColumnModel().removeColumnModelListener( this );
		tcm = table.getColumnModel();
		tcm.addColumnModelListener( this );

		//  Keep a duplicate TableColumns for managing hidden TableColumns

		int count = tcm.getColumnCount();
		allColumns = new ArrayList<TableColumn>(count);

		for (int i = 0; i < count; i++)
		{
			allColumns.add( tcm.getColumn( i ) );
		}
	}

	/**
	 *  Get the popup support.
	 *
	 *  @returns the popup support
	 */
	public boolean isMenuPopup()
	{
		return menuPopup;
	}

	/**
	 *  Add/remove support for a popup menu to the table header. The popup
	 *  menu will give the user control over which columns are visible.
	 *
	 *  @param  menuPopop when true support for displaying a popup menu is added
	 *					otherwise the popup menu is removed.
	 */
	public void setMenuPopup(boolean menuPopup)
	{
		table.getTableHeader().removeMouseListener( this );

		if (menuPopup)
			table.getTableHeader().addMouseListener( this );

		this.menuPopup = menuPopup;
	}

	/**
	 *  Hide a column from view in the table.
	 *
	 *  @param  modelColumn  the column index from the TableModel
	 *					   of the column to be removed
	 */
	public void hideColumn(int modelColumn)
	{
		int viewColumn = table.convertColumnIndexToView( modelColumn );

		if (viewColumn != -1)
		{
			TableColumn column = tcm.getColumn(viewColumn);
			hideColumn(column);
		}
	}

	/**
	 *  Hide a column from view in the table.
	 *
	 *  @param  columnName   the column name of the column to be removed
	 */
	public void hideColumn(Object columnName)
	{
		if (columnName == null) return;

		for (int i = 0; i < tcm.getColumnCount(); i++)
		{
			TableColumn column = tcm.getColumn( i );

			if (columnName.equals(column.getHeaderValue()))
			{
				hideColumn( column );
				break;
			}
		}
	}

	/**
	 *  Hide a column from view in the table.
	 *
	 *  @param  column  the TableColumn to be removed from the
	 *				  TableColumnModel of the table
	 */
	public void hideColumn(TableColumn column)
	{
		if (tcm.getColumnCount() == 1) return;

		//  Ignore changes to the TableColumnModel made by the TableColumnManager

		tcm.removeColumnModelListener( this );
		tcm.removeColumn( column );
		tcm.addColumnModelListener( this );
	}

	/**
	 *  Show a hidden column in the table.
	 *
	 *  @param  modelColumn  the column index from the TableModel
	 *					   of the column to be added
	 */
	public void showColumn(int modelColumn)
	{
		for (TableColumn column : allColumns)
		{
			if (column.getModelIndex() == modelColumn)
			{
				showColumn( column );
				break;
			}
		}
	}

	/**
	 *  Show a hidden column in the table.
	 *
	 *  @param  columnName   the column name from the TableModel
	 *					   of the column to be added
	 */
	public void showColumn(Object columnName)
	{
		for (TableColumn column : allColumns)
		{
			if (column.getHeaderValue().equals(columnName))
			{
				showColumn( column );
				break;
			}
		}
	}

	/**
	 *  Show a hidden column in the table. The column will be positioned
	 *  at its proper place in the view of the table.
	 *
	 *  @param  column   the TableColumn to be shown.
	 */
	private void showColumn(TableColumn column)
	{
		//  Ignore changes to the TableColumnModel made by the TableColumnManager

		tcm.removeColumnModelListener( this );

		//  Add the column to the end of the table

		tcm.addColumn( column );

		//  Move the column to its position before it was hidden.
		//  (Multiple columns may be hidden so we need to find the first
		//  visible column before this column so the column can be moved
		//  to the appropriate position)

		int position = allColumns.indexOf( column );
		int from = tcm.getColumnCount() - 1;
		int to = 0;

		for (int i = position - 1; i > -1; i--)
		{
			try
			{
				TableColumn visibleColumn = allColumns.get( i );
				to = tcm.getColumnIndex( visibleColumn.getHeaderValue() ) + 1;
				break;
			}
			catch(IllegalArgumentException e) {}
		}

		tcm.moveColumn(from, to);

		tcm.addColumnModelListener( this );
	}
//
//  Implement MouseListener
//
	public void mousePressed(MouseEvent e)
	{
		checkForPopup( e );
	}

	public void mouseReleased(MouseEvent e)
	{
		checkForPopup( e );
	}

	public void mouseClicked(MouseEvent e) {}
	public void mouseEntered(MouseEvent e) {}
	public void mouseExited(MouseEvent e) {}

	private void checkForPopup(MouseEvent e)
	{
		if (e.isPopupTrigger())
		{
			JTableHeader header = (JTableHeader)e.getComponent();
			int column = header.columnAtPoint( e.getPoint() );
			showPopup(column);
		}
	}

	/*
	 *  Show a popup containing items for all the columns found in the
	 *  table column manager. The popup will be displayed below the table
	 *  header columns that was clicked.
	 *
	 *  @param  index  index of the table header column that was clicked
	 */
	private void showPopup(int index)
	{
		Object headerValue = tcm.getColumn( index ).getHeaderValue();
		int columnCount = tcm.getColumnCount();
		JPopupMenu popup = new SelectPopupMenu();

		//  Create a menu item for all columns managed by the table column
		//  manager, checking to see if the column is shown or hidden.

		for (TableColumn tableColumn : allColumns)
		{
			Object value = tableColumn.getHeaderValue();
			JCheckBoxMenuItem item = new JCheckBoxMenuItem( value.toString() );
			item.addActionListener( this );

			try
			{
				tcm.getColumnIndex( value );
				item.setSelected( true );

				if (columnCount == 1)
					item.setEnabled( false );
			}
			catch(IllegalArgumentException e)
			{
				item.setSelected( false );
			}

			popup.add( item );

			if (value == headerValue)
				popup.setSelected( item );
		}

		//  Display the popup below the TableHeader

		JTableHeader header = table.getTableHeader();
		Rectangle r = header.getHeaderRect( index );
		popup.show(header, r.x, r.height);
	}
//
//  Implement ActionListener
//
	/*
	 *  A table column will either be added to the table or removed from the
	 *  table depending on the state of the menu item that was clicked.
	 */
	public void actionPerformed(ActionEvent event)
	{
		if (event.getSource() instanceof AbstractButton)
		{
			AbstractButton button = (AbstractButton)event.getSource();
			String column = event.getActionCommand();

			if (button.isSelected())
				showColumn(column);
			else
				hideColumn(column);
		}
	}
//
//  Implement TableColumnModelListener
//
	public void columnAdded(TableColumnModelEvent e)
	{
		//  A table column was added to the TableColumnModel so we need
		//  to update the manager to track this column

		TableColumn column = tcm.getColumn( e.getToIndex() );

		if (allColumns.contains( column ))
			return;
		else
			allColumns.add( column );
	}

	public void columnMoved(TableColumnModelEvent e)
	{
		if (e.getFromIndex() == e.getToIndex()) return;

		//  A table column has been moved one position to the left or right
		//  in the view of the table so we need to update the manager to
		//  track the new location

		int index = e.getToIndex();
		TableColumn column = tcm.getColumn( index );
		allColumns.remove( column );

		if (index == 0)
		{
			allColumns.add(0, column);
		}
		else
		{
			index--;
			TableColumn visibleColumn = tcm.getColumn( index );
			int insertionColumn = allColumns.indexOf( visibleColumn );
			allColumns.add(insertionColumn + 1, column);
		}
	}

	public void columnMarginChanged(ChangeEvent e) {}
	public void columnRemoved(TableColumnModelEvent e) {}
	public void columnSelectionChanged(ListSelectionEvent e) {}
//
//  Implement PropertyChangeListener
//
	public void propertyChange(PropertyChangeEvent e)
	{
		if ("model".equals(e.getPropertyName()))
		{
			if (table.getAutoCreateColumnsFromModel())
				reset();
		}
	}

	/*
	 *  Allows you to select a specific menu item when the popup is
	 *  displayed. (ie. this is a bug? fix)
	 */
	class SelectPopupMenu extends JPopupMenu
	{
		@Override
		public void setSelected(Component sel)
		{
			int index = getComponentIndex( sel );
			getSelectionModel().setSelectedIndex(index);
			final MenuElement me[] = new MenuElement[2];
			me[0]=(MenuElement)this;
			me[1]=getSubElements()[index];

			SwingUtilities.invokeLater(new Runnable()
			{
				public void run()
				{
					MenuSelectionManager.defaultManager().setSelectedPath(me);
				}
			});
		}
	};
}