/*
 * @(#)AbstractTableModel.java	1.28 00/02/02
 *
 * Copyright 1997-2000 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */

package javax.swing.table;

import javax.swing.*;
import javax.swing.event.*;
import java.io.Serializable;
import java.util.EventListener; 

/**
 *  This abstract class provides default implementations for most of
 *  the methods in the <code>TableModel</code> interface. It takes care of
 *  the management of listeners and provides some conveniences for generating
 *  <code>TableModelEvents</code> and dispatching them to the listeners.
 *  To create a concrete <code>TableModel</code> as a sublcass of
 *  <code>AbstractTableModel</code> you need only provide implementations 
 *  for the following three methods:
 *
 *  <pre>
 *  public int getRowCount();
 *  public int getColumnCount();
 *  public Object getValueAt(int row, int column);
 *  </pre>
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases.  The current serialization support is appropriate
 * for short term storage or RMI between applications running the same
 * version of Swing.  A future release of Swing will provide support for
 * long term persistence.
 *
 * @version 1.28 02/02/00
 * @author Alan Chung
 * @author Philip Milne
 */
public abstract class AbstractTableModel implements TableModel, Serializable
{
//
// Instance Variables
//

    /** List of listeners */
    protected EventListenerList listenerList = new EventListenerList();

//
// Default Implementation of the Interface
//

    /**
     *  Returns a default name for the column using spreadsheet conventions:
     *  A, B, C, ... Z, AA, AB, etc.  If <code>column</code> cannot be found,
     *  returns an empty string.
     *
     * @param column  the column being queried
     * @return a string containing the default name of <code>column</code>
     */
    public String getColumnName(int column) {
	String result = "";
	for (; column >= 0; column = column / 26 - 1) {
	    result = (char)((char)(column%26)+'A') + result;
	}
        return result;
    }

    /**
     * Returns a column given its name.
     * Implementation is naive so this should be overridden if
     * this method is to be called often. This method is not
     * in the <code>TableModel</code> interface and is not used by the
     * <code>JTable</code>.
     *
     * @param columnName string containing name of column to be located
     * @return the column with <code>columnName</code>, or -1 if not found
     */
    public int findColumn(String columnName) {
        for (int i = 0; i < getColumnCount(); i++) {
            if (columnName.equals(getColumnName(i))) {
                return i;
            }
        }
        return -1;
    }

    /**
     *  Returns <code>Object.class</code> regardless of <code>columnIndex</code>.
     *
     *  @param columnIndex  the column being queried
     *  @return the Object.class
     */
    public Class getColumnClass(int columnIndex) {
	return Object.class;
    }

    /**
     *  Returns false.  This is the default implementation for all cells.
     *
     *  @param  rowIndex  the row being queried
     *  @param  columnIndex the column being queried
     *  @return false
     */
    public boolean isCellEditable(int rowIndex, int columnIndex) {
	return false;
    }

    /**
     *  This empty implementation is provided so users don't have to implement
     *  this method if their data model is not editable.
     *
     *  @param  aValue   value to assign to cell
     *  @param  rowIndex   row of cell
     *  @param  columnIndex  column of cell
     */
    public void setValueAt(Object aValue, int rowIndex, int columnIndex) {
    }


//
//  Managing Listeners
//

    /**
     * Adds a listener to the list that's notified each time a change
     * to the data model occurs.
     *
     * @param	l		the TableModelListener
     */
    public void addTableModelListener(TableModelListener l) {
	listenerList.add(TableModelListener.class, l);
    }

    /**
     * Removes a listener from the list that's notified each time a
     * change to the data model occurs.
     *
     * @param	l		the TableModelListener
     */
    public void removeTableModelListener(TableModelListener l) {
	listenerList.remove(TableModelListener.class, l);
    }

//
//  Fire methods
//

    /**
     * Notifies all listeners that all cell values in the table's
     * rows may have changed. The number of rows may also have changed
     * and the <code>JTable</code> should redraw the
     * table from scratch. The structure of the table (as in the order of the
     * columns) is assumed to be the same.
     *
     * @see TableModelEvent
     * @see EventListenerList
     */
    public void fireTableDataChanged() {
        fireTableChanged(new TableModelEvent(this));
    }

    /**
     * Notifies all listeners that the table's structure has changed.
     * The number of columns in the table, and the names and types of
     * the new columns may be different from the previous state.
     * If the <code>JTable</code> receives this event and its
     * <code>autoCreateColumnsFromModel</code>
     * flag is set it discards any table columns that it had and reallocates
     * default columns in the order they appear in the model. This is the
     * same as calling <code>setModel(TableModel)</code> on the
     * <code>JTable</code>.
     *
     * @see TableModelEvent
     * @see EventListenerList
     */
    public void fireTableStructureChanged() {
        fireTableChanged(new TableModelEvent(this, TableModelEvent.HEADER_ROW));
    }

    /**
     * Notifies all listeners that rows in the range
     * <code>[firstRow, lastRow]</code>, inclusive, have been inserted.
     *
     * @param  firstRow  the first row
     * @param  lastRow   the last row
     *
     * @see TableModelEvent
     * @see EventListenerList
     *
     */
    public void fireTableRowsInserted(int firstRow, int lastRow) {
        fireTableChanged(new TableModelEvent(this, firstRow, lastRow,
                             TableModelEvent.ALL_COLUMNS, TableModelEvent.INSERT));
    }

    /**
     * Notifies all listeners that rows in the range
     * <code>[firstRow, lastRow]</code>, inclusive, have been updated.
     *
     * @param firstRow  the first row
     * @param lastRow   the last row
     *
     * @see TableModelEvent
     * @see EventListenerList
     */
    public void fireTableRowsUpdated(int firstRow, int lastRow) {
        fireTableChanged(new TableModelEvent(this, firstRow, lastRow,
                             TableModelEvent.ALL_COLUMNS, TableModelEvent.UPDATE));
    }

    /**
     * Notifies all listeners that rows in the range
     * <code>[firstRow, lastRow]</code>, inclusive, have been deleted.
     *
     * @param firstRow  the first row
     * @param lastRow   the last row
     *
     * @see TableModelEvent
     * @see EventListenerList
     */
    public void fireTableRowsDeleted(int firstRow, int lastRow) {
        fireTableChanged(new TableModelEvent(this, firstRow, lastRow,
                             TableModelEvent.ALL_COLUMNS, TableModelEvent.DELETE));
    }

    /**
     * Notifies all listeners that the value of the cell at 
     * <code>[row, column]</code> has been updated.
     *
     * @param row  row of cell which has been updated
     * @param column  column of cell which has been updated
     * @see TableModelEvent
     * @see EventListenerList
     */
    public void fireTableCellUpdated(int row, int column) {
        fireTableChanged(new TableModelEvent(this, row, row, column));
    }

    /**
     * Forwards the given notification event to all
     * <code>TableModelListeners</code> that registered
     * themselves as listeners for this table model.
     *
     * @param e  the event to be forwarded
     *
     * @see #addTableModelListener
     * @see TableModelEvent
     * @see EventListenerList
     */
    public void fireTableChanged(TableModelEvent e) {
	// Guaranteed to return a non-null array
	Object[] listeners = listenerList.getListenerList();
	// Process the listeners last to first, notifying
	// those that are interested in this event
	for (int i = listeners.length-2; i>=0; i-=2) {
	    if (listeners[i]==TableModelListener.class) {
		((TableModelListener)listeners[i+1]).tableChanged(e);
	    }
	}
    }

    /**
     * Returns an array of all the listeners of the given type that 
     * were added to this model. 
     *
     * @returns all of the objects receiving <code>listenerType</code>
     *		notifications from this model
     * 
     * @since 1.3
     */
    public EventListener[] getListeners(Class listenerType) { 
	return listenerList.getListeners(listenerType); 
    }
} // End of class AbstractTableModel