package antlr.collections.impl;
/* ANTLR Translator Generator
* Project led by Terence Parr at http://www.jGuru.com
* Software rights: http://www.antlr.org/RIGHTS.html
*
* $Id: //depot/code/org.antlr/release/antlr-2.7.2/antlr/collections/impl/LLEnumeration.java#1 $
*/
import antlr.collections.List;
import antlr.collections.Stack;
import java.util.Enumeration;
import java.util.NoSuchElementException;
import antlr.collections.impl.LLCell;
/**An enumeration of a LList. Maintains a cursor through the list.
* bad things would happen if the list changed via another thread
* while we were walking this list.
*/
final class LLEnumeration implements Enumeration {
LLCell cursor;
LList list;
/**Create an enumeration attached to a LList*/
public LLEnumeration(LList l) {
list = l;
cursor = list.head;
}
/** Return true/false depending on whether there are more
* elements to enumerate.
*/
public boolean hasMoreElements() {
if (cursor != null)
return true;
else
return false;
}
/**Get the next element in the enumeration. Destructive in that
* the returned element is removed from the enumeration. This
* does not affect the list itself.
* @return the next object in the enumeration.
*/
public Object nextElement() {
if (!hasMoreElements()) throw new NoSuchElementException();
LLCell p = cursor;
cursor = cursor.next;
return p.data;
}
}