Comments on: Java Enumeration and Iterators

By: rgz

rgz — Wed, 16 Sep 2009 23:36:01 +0000

I just figured out that we can do this for exactly the same cost and the intention read a bit more clearly.

for(Enumeration e = foos.getEnumeration(); e.hasMoreElements(); Foo foo = e.nextElement()){
// process foo
}

By: Nevor

Nevor — Mon, 24 Aug 2009 10:17:50 +0000

and a O(1) random access

By: Nevor

Nevor — Mon, 24 Aug 2009 10:14:42 +0000

Method calls are clearly not “1 operation” and furthermore you forget about the item.next() which is called at each loop. Thus, with a collection that has a O(1) get size, the for loop is more efficient than the iterator.

By: yonas

yonas — Mon, 20 Jul 2009 22:51:47 +0000

v.hasNext() and v.hasMoreElements() are not equal to 1 operation, each.

If you break it down to CPU cycles needed to run those functions, I guarantee you that they are AT LEAST as many CPU cycles as a for loop.

Moreover, the compiler might simplify things like "int i = 0" to one operation.

By: Dharmesh Gupta

Dharmesh Gupta — Tue, 26 May 2009 00:49:57 +0000

First, Enumerator was introduced in jdk 1.2. now we are using iterator.
The place where we can use both use iteartor.

By using Enumerator we can only retrieve values, means forward only.
But by using Iterator, we can retrieve, delete, or change the values.

So, good to use Iterator.

By: Dharmesh Gupta

Dharmesh Gupta — Tue, 26 May 2009 00:48:29 +0000

By: mohan

mohan — Wed, 13 May 2009 20:56:04 +0000

dayNames.add(”Saturday”};—>error

By: swetha

swetha — Mon, 27 Apr 2009 05:34:37 +0000

Very Usefull and clear explanation

By: Lahar

Lahar — Tue, 17 Feb 2009 13:16:04 +0000

Enumeration is same as Iterator.
and working of both are same but Main differnce is Iterator has remove().
remove() removes the last object taken using next().

By: gunjan garg

gunjan garg — Sat, 31 Jan 2009 12:56:34 +0000

what is the difference in Enumeration and Iterator?if they are same then why we read these two different concepts