Modulo ClassCastException and the like (e.g. instanceof checks), Java arrays are compiles straight into JavaScript arrays; while collections have an emulated "wrapper" class around a JavaScript array. However, due to how the compiler inlines methods, most accesses to a collection's item (i.e. by index) only involve a single additional step cmpared to using Java arrays: dereferencing the property ofthe collection object containing the JS array (this is assuming a java.util.List, of course things are different with java.util.Set, for instance). Where things ge more different is for "for (... : ...)" loops, which are translated into "for (int i=0,l=array.length; i< l; i++)" loops for arrays, but use an emulated java.util.Iterator for collections.
That being said, given the speed of today's JS engines it should not make a difference (maybe on IE6 ? on mobiles ?) I'd personnally stick with collections if they better fit your use case (variable length, inserting/removing values, etc.) as your code will be more readable and thus more maintainable. And only if performance is an issue then investigate, but there will probably be other bottlenecks than arrays vs. collections! (widgets, DOM manipulations, network, including building and parsing request/response payload, etc.) -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to google-web-tool...@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
