GWT Developers Plugin for Firefox 10

https://dl.google.com/dl/gwt/plugins/firefox/1.0.10862/gwt-dev-plugin.xpi

Convert byte size into human readable format in Java ( and GWT )

Java:

public static String humanReadableByteCount(long bytes, boolean si) {
    int unit = si ? 1000 : 1024;
    if (bytes < unit) return bytes + " B";
    int exp = (int) (Math.log(bytes) / Math.log(unit));
    String pre = (si ? "kMGTPE" : "KMGTPE").charAt(exp-1) + (si ? "" : "i");
    return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre);
}

Java GWT:

public static String humanReadableByteCount(long bytes, boolean si) {
 int unit = si ? 1000 : 1024;
 if (bytes < unit)
  return bytes + " B";
 int exp = (int) (Math.log(bytes) / Math.log(unit));
 String pre = (si ? "kMGTPE" : "KMGTPE").charAt(exp - 1)
   + (si ? "" : "i");
 return toFixed(bytes / Math.pow(unit, exp), 1) + " " + pre
    + "B";
}
public static native String toFixed(double d, int fixed)/*-{
  return d.toFixed(fixed);
}-*/;

Orgin from here

JSNI function in GWT to format numbers

public class NumberUtil {
 
 public static native String toFixed(double d, int fixed)/*-{
  return d.toFixed(fixed);
 }-*/;
 
 public static native String toPrecision(double d, int precision)/*-{
  return d.toPrecision(precision);
 }-*/;

}

see also this article.

Format numbers in javascript

var num = 1;
var result = num.toFixed(2); // result = 1.00

num = 123.4567;
result = num.toFixed(3); // result = 123.456

num = 123.4567;
result = num.toPrecision(4); // result = 123.4

num = 123.4567;
result = num.toPrecision(3); // result = 123

num = 555.55;
result = num.toPrecision(2); // result will equal 5.6e+2

see also this article.

GWT: JSNI function to validate URL

public native boolean isValidUrl(String url) /*-{
    var pattern = /(http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/;
    return pattern.test(url);
}-*/;