/* 
 * This file is part of the Echo2 Table Extension (hereinafter "ETE").
 * Copyright (C) 2002-2005 NextApp, Inc.
 *
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 */
package echopointng.table;

import java.util.Collections;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.List;

import nextapp.echo2.app.table.DefaultTableModel;
import nextapp.echo2.app.table.TableColumn;
import nextapp.echo2.app.table.TableColumnModel;

/**
 * The default implementation for the <code>SortableTableModel</code>
 * interface.  The sort algorithm is deferred to Collections.sort()
 * 
 * @author Jason Dalton
 * 
 */
public class DefaultSortableTableModel extends DefaultTableModel implements  SortableTableModel {

    private boolean ascending;
    private int currentColumn;
    private TableColumnModel columnModel;
    
    public DefaultSortableTableModel(TableColumnModel columnModel) {
        this.columnModel = columnModel;
    }
    
    /** 
     * @see echopointng.table.SortableTableModel#sortByColumn(int, boolean)
     */
    public void sortByColumn(int column, boolean ascending) {
        this.currentColumn = column;
        this.ascending = ascending;
        
        List rows = getRows();
        TableColumn tableColumn = columnModel.getColumn(column);
        if (tableColumn instanceof SortableTableColumn) {
            SortableTableColumn sortColumn = (SortableTableColumn) tableColumn;
            RowComparator comparator = new RowComparator(sortColumn,ascending);
            Collections.sort(rows,comparator);
            setRows(rows);
        }
    }
    
    /**
     * Creates a List of Lists based on the data backing this model
     * in the superclass.
     */
    protected List getRows() {
        List rows = new LinkedList();
        for (int i=0; i<getRowCount(); i++){
            List row = new LinkedList();
            for (int j=0; j<getColumnCount(); j++) {
                row.add(j,getValueAt(j,i));
            }
            rows.add(row);
        }
        return rows;
    }
    
    /**
     * Synchronizes the given List of Lists to the data backing 
     * this model in the superclass.
     */
    protected void setRows(List rows) {
        for (int i=0; i<rows.size(); i++){
            List row = (List) rows.get(i);
            for (int j=0; j<getColumnCount(); j++) {
                setValueAt(row.get(j),j,i);
            }
        }
    }
    
    /**
     * @see echopointng.table.SortableTableModel#getCurrentSortColumn()
     */
    public int getCurrentSortColumn() {
        return currentColumn;
    }

    /**
     * @see echopointng.table.SortableTableModel#isCurrentSortAscending()
     */
    public boolean isCurrentSortAscending() {
        return ascending;
    }
}

/**
 * Comparator for the List of Lists backing the model.
 * The actual comparison is performed by the given 
 * <code>SortableTableColumn</code>'s <code>Comparator</code>
 * property.
 */
class RowComparator implements Comparator {
    private SortableTableColumn column;
    private boolean ascending;
    
    RowComparator(SortableTableColumn column, boolean ascending){
        this.column = column;
        this.ascending = ascending;
    }
    
    public int compare(Object o1, Object o2) {
        if (o1 == null || o2 == null){
            return 0;
        } else {
            List first = (List) o1;
            List second = (List) o2;
            int index = column.getModelIndex();
            Comparator comparator = column.getComparator(); 
            if (ascending) {
                return comparator.compare(first.get(index),second.get(index));
            } else {
                return comparator.compare(second.get(index),first.get(index));
            }
        }
    }
}