downloadstablemodel.java

一个网络上传下载器

package DownloadManager;

import java.util.*;
import javax.swing.*;
import javax.swing.table.*;


/**
 This class manages the download table's data.
 @author Liu Yu Yang
 */
class DownloadsTableModel extends AbstractTableModel
        implements Observer {
    // These are the names for the table's columns.
    private static final String[] columnNames = {"File name", "File size",
    "Used Time", "Status"};
    
    // These are the classes for each column's values.
    private static final Class[] columnClasses = {String.class,
    String.class, String.class, String.class};
    
    // The table's list of downloads.
    private ArrayList downloadList = new ArrayList();
    
    // Add a new download to the table.
    @SuppressWarnings("unchecked")
    public void addDownload(Download download) {
        // Register to be notified when the download changes.
        download.addObserver(this);
        
        downloadList.add(download);
        
        // Fire table row insertion notification to table.
        fireTableRowsInserted(getRowCount() - 1, getRowCount() - 1);
    }
    
    // Get a download for the specified row.
    public Download getDownload(int row) {
        return (Download) downloadList.get(row);
    }
    
    // Remove a download from the list.
    public void clearDownload(int row) {
        downloadList.remove(row);
        
        // Fire table row deletion notification to table.
        fireTableRowsDeleted(row, row);
    }
    
    // Get table's column count.
    public int getColumnCount() {
        return columnNames.length;
    }
    
    // Get a column's name.
    @Override
    public String getColumnName(int col) {
        return columnNames[col];
    }
    
    // Get a column's class.
    @Override
    public Class getColumnClass(int col) {
        return columnClasses[col];
    }
    
    // Get table's row count.
    public int getRowCount() {
        return downloadList.size();
    }
    
    // Get value for a specific row and column combination.
    public Object getValueAt(int row, int col) {
        Download download = (Download) downloadList.get(row);
        switch (col) {
            case 0: // URL
                return download.getFileName();
            case 1: // Size
                long size = download.getSize();
                return (size == -1) ? "" : String.valueOf(size);
            case 2: // Progress
                return new Float(download.getUsedTime());
            case 3: // Status
                return Download.STATUSES[download.getStatus()];
        }
        return "";
    }
    
  /* Update is called when a Download notifies its
     observers of any changes */
    public void update(Observable o, Object arg) {
        int index = downloadList.indexOf(o);
        // Fire table row update notification to table.
        fireTableRowsUpdated(index, index);
    }
}