Moxie Group: GWT Uploader

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What is it?

GWT Uploader is a freely available open source GWT library that encapsulates the file upload capabilities provided by the File and XMLHttpRequest Level 2 APIs as well as the SWFUpload library.

Using GWT Uploader allows for enhanced file upload dialogs (multiple uploads, drag and drop, queues, parallel streams, etc.) and interactive interfaces (upload progress indicators, real-time throughput display, upload cancellation, etc.) within GWT applications using pure Java code that provides a consistent experience across all browsers.

If the browser is capable of handling file uploads using a modern HTML5 approach, the upload is handled using pure DOM elements and Javascript events. In the case that the browser does not support the modern approach (most notably IE 9 and earlier), the GWT Uploader component instead transparently handles the uploads via the Flash-based SWFUpload library.

Quick links:

Key Features:

Simple	Adds consistent file upload support to all modern browsers with a single implementation, while still supporting legacy browsers automatically.
Pure Java	The entire set of file upload capabilities are available via GWT powered Java methods (even in the case that the SWFUpload library is used), including clean interfaces for the various runtime callbacks (no need to write any JavaScript).
Customizable Interfaces	GWT Uploader exposes all the file upload capabilities as a GWT Widget, making it easy to create your own aesthetic for your upload controls or leave it simple and benefit from the multiple file selection and queued uploading. Convenient methods are also provided to enable file uploads via a familiar drag and drop approach.
Clean Syntax	The API is built using fluent methods that allow you to manage the configuration options of the the upload control using syntax that is nearly as tight as JSON.
Dynamic	GWT Uploader automatically includes the necessary plugin capabilities to expose various throughput and performance metrics of the uploads during and after an upload. Each File object has the following properties: getAverageSpeed() -- Overall average upload speed, in bytes per second getCurrentSpeed() -- String indicating the upload speed, in bytes per second getMovingAverageSpeed() -- Speed over averaged over the last several measurements, in bytes per second getPercentUploaded() -- Percentage of the file uploaded (0 to 100) getSizeUploaded() -- Formatted size uploaded so far, bytes getTimeElapsed() -- Number of seconds passed for this upload getTimeRemaining() -- Estimated remaining upload time in seconds These metrics allow for dynamic updates to occur in your interface, whether it's progress bars or text labels, as data is transferred for one or more files.
Documented	Every class and method of the API is thoroughly documented, including numerous code and syntax examples throughout.
Examples	The demonstration examples provide several basic examples of upload interfaces that demonstrate the flexibility and integration opportunities available, with each example including a convenient "View Source" button that will allow you to see the code behind each implementation.