Friday, October 5th, 2007
Joe Walker shows a tip from DWR.Next
Category: DWR, Java
, JavaScript
What is cool about this is that the APIs from Java and JavaScript lands feel right in each, but to do this DWR has to do a lot of fancy work to hide the details.
In Java land you write something like the following, which uses Java BufferedImages.
JAVA:
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public class FileUploader {
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...
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uploadImage = scaleToSize(uploadImage);
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uploadImage = grafitiTextOnImage(uploadImage, uploadFile, color);
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return uploadImage;
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}
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...
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}
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But a BufferedImage means nothing to JavaScript, but that is fine... in JavaScript land you just use the nodes (or so you think).
JAVASCRIPT:
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function uploadFiles() {
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var image = dwr.util.getValue('uploadImage');
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var file = dwr.util.getValue('uploadFile');
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var color = dwr.util.getValue('color');
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FileUploader.uploadFiles(image, file, color, function(data) {
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dwr.util.setValue('image', data);
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});
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}
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Anyway, let's watch Joe explain:
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3.8 rating from 16 votes
Who’s “Joe” and what is “DWR”?
If you’re stuck in Java-land, DWR (Direct Web Remoting) is a dream come true. It lets Javascript be Javascript, and the Java side never knows the difference.
I doubt that it’s a compelling reason to bet the farm on Java, though, if you’re already productive on some other platform.
Joe also gave a pretty cool/disturbing presentation with Jeremiah Grossman at the SF Ajax Experience on web security. I can’t speak for the Java side, but browsers are pretty bare-bones when it comes to handling files via form elements.
That presentation on security was my favorite from the conference, I loved the stuff on anti-DNS pinning, when they hacked into the router using JS and were able to remotely send JS code directly to the hijacked browser.
@Scott, Kris: Don’t suppose you know where to find those presentations do you? :)