Sunday, September 30, 2012

Iterators class example in java

Today I had to use Iterators over a Java List, Java's documentation on Iterator lacks  a good example,here is a  good example about Iterator class.
diagram for iterator class in java

The List and Set collections provide iterators, which are objects that allow going over all the elements of a collection in sequence. The java.util.Iterator interface provides for one-way traversal and java.util.ListIterator provides two-way traversal. Iterator is a replacement for the older Enumeration class which was used before collections were added to Java.

Let say we have an object of ArrayList class name "myList"  . to implement an iterator on a list we should it intialize it on "myList"
Iterator it = myList.iterator();

Iterator methods are :

myList.hasNext()
Returns boolean true or false.
myList.next()
Returns the next object.(with the list's type).
myLlist.revmoe()
Removes the most recent element that was returned by next.


An iterator might be used as follows:

//initializing a list in Java
ArrayList alist = new ArrayList();

//  Add Strings to alist
myList.add("flower");
mList.add("kurdistan");
myList.add("sun");
myList.add("mountain");


for (Iterator it = myList.iterator(); it.hasNext(); ) {
    String s = (String)it.next(); 
    System.out.println(s);
}


Post a Comment

Related

Labels

computer (48) ubuntu (46) linux (28) tutorial (20) opinion (17) programming (14) software overview (13) terminal (12) troubleshooting (8) life (7) literature (7) poem (7) human languages (6) vim (6) bash (5) google (5) python (5) android (4) cars (4) phpBB (4) suggestion (4) tips (4) 12.04 (3) Chef (3) extension and addons (3) firefox (3) java (3) personal (3) russian (3) shell (3) windows (3) 64bit (2) Calligraphy (2) Chicago (2) Vagrant (2) apple (2) backup (2) bug (2) code (2) eclipse (2) funny (2) google chrome (2) idea (2) monitor (2) php (2) phpBB3 (2) shorter prompt (2) ssh (2) virtualbox (2) $_SERVER['REQUEST_URI'] (1) 2.7 (1) ALT+Backspace (1) AVR (1) Alt-Printscreen-K (1) AutoRotate (1) CTRL+ALT+DELETE (1) DRM (1) Debugging (1) Gimp (1) Gimp 2.8 (1) Microcontroler (1) Restart X (1) UML (1) Ventra (1) adsense (1) amazon (1) audio (1) aws (1) background process (1) battery (1) bing (1) blank (1) blogging (1) bmw (1) boot (1) business review (1) car (1) cd (1) chrome (1) comcast (1) computer kubuntu (1) conference (1) cookie (1) cron (1) database (1) date (1) display (1) domain name (1) download manager (1) dual boot (1) dual monitor (1) extensions (1) feature request (1) file (1) folder (1) freeze (1) gimp single window (1) git (1) gnome 3.10 (1) google docs (1) google plust (1) google+ (1) grep (1) icon (1) install (1) iterator (1) links (1) linu (1) linux links (1) list (1) mac os (1) media server (1) microsoft (1) moonlight (1) music (1) mysql (1) name (1) nautilus (1) netflix (1) notepad++ (1) parking (1) permission (1) philosophy (1) photo (1) prompt (1) protest (1) ps3mediaserver (1) putty (1) read from file (1) realtek (1) resolution (1) roku (1) samsung (1) scala (1) screenshot (1) security (1) selinux (1) server (1) skype (1) space (1) spam (1) spambot (1) sql (1) suspension (1) system monitor (1) tar (1) task manager (1) template design (1) th23 domain (1) thinking (1) ubuntu 13.10 (1) unity (1) vimrc (1) virtual machine (1) weblogic (1) wget (1) with space (1) xorg (1) xrand (1)