Code:private ArrayList<DemoModule> demosList = new ArrayList<DemoModule> ();
Code:for (SwingSet2 ss : swingSets) {
ss.updateThisSwingSet();
}
I haven't seen these in my old books. :(
And well right now they are causing some errors on my eclipse editor... But these snippets are from the demo projects shipped with java 1.5 so I think they should be working right?
How do I make the errors go away?
And what's the purpose of these constructs?
That's because the old books don't mention new features. Those things are new in Java5.Quote:
I haven't seen these in my old books.
This is called generics. ArrayList is a generic class. This particular version of ArrayList can only store DemoModule and subclass instances. This increases typesafety and reduces keystrokes (because you don't have to cast on retrieval).Quote:
private ArrayList<DemoModule> demosList = new ArrayList<DemoModule> ();
The advanced for-loop or foreach-loop. This code is effectively equivalent to, but much shorter than, this:Quote:
for (SwingSet2 ss : swingSets) {
Code:for(Iterator it = swingSets.iterator(); it.hasNext(); ) {
SwingSet2 ss = (SwingSet2)it.next();
Download the newest version of Eclipse and hope that it supports Java5.Quote:
How do I make the errors go away?
I see... Thanks a lot. I guess I have to check out the other features of java1.5 as well. :D
Very weird syntax. :sick: Haven't looked at the new features of 1.5 yet but i think this scjp exam book ive been reading should talk about them soon. I hope. :rolleyes: About the for loop. Where is the actual initialization;loopcondition?
Code:for (SwingSet2 ss : swingSets) {
Yeah... it needs some kind of getting used to.
Nowhere. It still uses the keyword 'for' (because the engineers didn't want to introduce yet another keyword - they already introduced 'enum', which already creates huge incompatibility problems), but it's really a 'foreach' loop. Look at PHP's foreach loop, it works exactly like that, except that the arguments are reversed. Or look at C#'s foreach loop, that works exactly the same way, with the keyword 'in' instead of the colon.Quote:
About the for loop. Where is the actual initialization;loopcondition?