Thread: applet loading time

My applet takes about 1 minute to load which I think is too much!? It is a 180kb application with about fourty 1kb GIF files, and a total of 70 classes all in one jar file. About half of the classes are inner classes mostly as action listeners for menu items. I started using too many of those after I read it is a good OO design. Should I go ahead and try to reduce the number of classes? Would it even be a significant improvement? I am not sure if it is wise to spend time on this because I think using JNLP solves my problem (it loads in less than a second). But I wonder what is the best practice regarding relative number of inner classes?

My second question is about the keyword "protected". What exactly does it do ? I thought it wouldn't allow non-derived classes access but it seems to me it is acts like the public keyword ?

Are all the images in the jar file?
Are you running it from local files or over the internet?

Originally Posted by Norm

Are all the images in the jar file?
Are you running it from local files or over the internet?

The images are in a sub directory inside the jar file. In local mode the images are loaded instantly hence no problem.
That is also the case when opening it from a browser as long as I use local files. However uploading the one jar file on google
sites and loading the applet takes about a minute. About 53 seconds is consumed within the class that loads the images.
My internet connection is pretty fast. Deploying the applet as a JNLP takes about a second to load an execute... I think if I can force the jar file to be loaded at once, maybe it will help reduce applet loading time. I found a discussion with slow image loading in applets even when run in local mode here Image loading very slow from URL (Applets forum at JavaRanch) . But in my case that happens only when loaded over the internet.

I don't know why the browser wouldn't load the jar file with all the images before the program started and from then on would be as fast as if it had loaded the jar file locally.
I wouldn't think the browser would be able to get data from a partially loaded jar file. But maybe it can get some data out of the jar file without having read the whole jar file.???

Do you have a server you can use that would show the interactions with the browser while the jar is being loaded to see how many times the browser calls the server while loading the applet's files?

Originally Posted by copeg

Try to load images using the ImageIO utility class as opposed to loading the image through the ImageIcon (which not only creates an unused object, but uses Toolkit.createImage method that according to the API goes through security checks and on my system this is considerably slower)

Indeed that helped reduce applet loading time to 40 secs. But I can not apply filters on the buffered image because it is indexed (from error message), so I did the test without that. It may go back up once that is added though.

static void getBufImage (String image_name,Integer index,BufferedImageOp op) {
    try {
    	InputStream is = BoardPanel.class.getResourceAsStream(image_name);
    	BufferedImage bimage = ImageIO.read(is);
               IMAGES.put(index,bimage);
    } catch (Exception e) {
    	JavaBoard.printMessage("Error :" + e.getMessage());
    }
}

One other thing , Google sites does not allow java scripts and applets so I am using a gadget to embed them.
Maybe that adds to the security issue.
More later.

Google sites does not allow java scripts and applets so I am using a gadget to embed them.

Can you explain how that works?

Originally Posted by Norm

Can you explain how that works?

I have a google gadget XML file that I use to run java scripts and applets on that server. It is a hack I found here. The XML file is as follows

<?xml version="1.0" encoding="UTF-8" ?>
<Module>
<ModulePrefs title="Custom Gadget" /> 
<Content type="html"><![CDATA[ 
 
    <script type="text/javascript" src="http://www.java.com/js/deployJava.js">
    </script>
 
    <script type="text/javascript">
          var attributes = { 
            code: 'javaboard.JavaBoard',
            archive: 'https://sites.google.com/site/dshawul/javaboard.jar',
            width: 970, 
            height: 700
          };
          var parameters = { };
          var version = '1.5';
          deployJava.runApplet(attributes, parameters, version);
     </script>
 
]]></Content> 
</Module>

I now notice that the link to the jar file is a secure https..
Then I insert the gadget by url link to the xml file once that is uploaded on the server.

TY

Thanks for that.

The loading time is further reduced and now is about 20-23 sec. Earlier I was loading the same image twice before applying a filter. So I load some image and apply Orange & Green filter to it to get two separate images. Well I now merged those two and the loading time is about halved. But you would expect the class loader will cache the image , but surprisingly that is not the case even within the same application.
A minor problem is that the filtering results in slightly different color than expected. I think it is because I am working on the same bufferedimage for the second filtering operation. Is there a way to do "deep cloning" on bufferedimage ?

static void getBufImage (String image_name,Integer index,BufferedImageOp[] op) {
    try {
    	java.net.URL imageURL = BoardPanel.class.getResource(image_name);
		Image image = new ImageIcon(imageURL).getImage();
		BufferedImage bimage = new BufferedImage(image.getWidth(null), 
	    		image.getHeight(null), BufferedImage.TYPE_INT_ARGB);
 
    	bimage.getGraphics().drawImage(image, 0, 0, null);
    	bimage = op[0].filter(bimage, null);
    	IMAGES.put(index + 'A',bimage);
    	bimage = op[1].filter(bimage, null);
    	IMAGES.put(index + 'a',bimage);
    } catch (Exception e) {
    	JavaBoard.printMessage("Error :" + e.getMessage());
    }
}

One final push may result in fastest applet loading. If I load just one image and use it every where the others are needed, the applet starts in maximum_ of 2-3 seconds! The gifs are 50x50 pixels each so I am trying to combine 152 of those files into one big gif file, and then load sections of that image into a buffered image. I was googling for tools to do just that but luckily java has it already. Always surprises me how many libraries java has stacked in it!

try {
	BufferedImage bimage = new BufferedImage(50 * 26, 
	   		50 * 26, BufferedImage.TYPE_INT_ARGB);
	Graphics g = bimage.getGraphics();
	for(int i = 0;i < 26;i++) {
		BufferedImage bi = IMAGES.get(i + 'A');
		g.drawImage(bi,50 * i,0,null);
	}
	File outputfile = new File("saved.png");
	    ImageIO.write(bimage, "png", outputfile);
 
	} catch (IOException e) {
        }

@copeg, Yes that should work I think. But now that I am using one gif file I may not need
to make a copy. Thanks.