downloadactionlistener.java

MyDownloader 是一款使用 http 协议(RFC 1867)用于下载一个或多个文件到本地的简单易用的收费 Java 程序.使用托拽操作,你可以在一个页面内下载多个文件.在下载文件的过程当中

/*
 * Copyright 2007 JavaAtWork All rights reserved.
 * Use is subject to license terms.
 */
package com.javaatwork.mydownloader.listeners;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;

import javax.swing.JFileChooser;
import javax.swing.JOptionPane;

import com.javaatwork.mydownloader.DownloadFile;
import com.javaatwork.mydownloader.MyDownloader;
import com.javaatwork.mydownloader.dialog.CenteredFileChooser;
import com.javaatwork.mydownloader.utils.LocaleManager;

/**
 * Class which is responsible for downloading the files.
 * 
 * @author Johannes Postma
 */
public class DownloadActionListener implements ActionListener {

	private MyDownloader myDownloader = null;
	
	/**
	 * Creates a new DownloadActionListener. This listener listens to
	 * the download button.
	 * 
	 * @param myDownloader The applet.
	 */
	public DownloadActionListener(MyDownloader myDownloader) {
		this.myDownloader = myDownloader;
	}
	
	/**
	 * Will be invoked when the action has taken place.
	 * 
	 * @param e The ActionEvent.
	 */
	public void actionPerformed(ActionEvent e) {
		
		// check if a file is selected
		final DownloadFile[] files = myDownloader.getFilesToDownload();

		if (files == null || files.length == 0) {
			return;
		}
		
		CenteredFileChooser fileChooser = new CenteredFileChooser();
		int returnValue = fileChooser.showSaveDialog(myDownloader);
		
		if (returnValue == JFileChooser.APPROVE_OPTION) {
			
			File directory = fileChooser.getSelectedFile();
			
			if (!directory.exists()) {
				
				String message = LocaleManager.getInstance().getString("directory_does_not_exist");
				message = message.replaceAll("<directory>", directory.toString());
				myDownloader.showMessage(message, JOptionPane.INFORMATION_MESSAGE);				
			
			} else {
			
				// download files
				DownloadManager downloadManager = new DownloadManager();
				downloadManager.downloadFiles(myDownloader, directory);
			}			
		}
		
	}

}