package dk.itu.oop.lecture5;

import java.util.Iterator;

public abstract class MergeIterators implements OOPIterator {
	private OOPIterator itr1,itr2;
	private Object nextElement;
	
	public MergeIterators(OOPIterator itr1, OOPIterator itr2){
		this.itr1 = itr1;
		this.itr2 = itr2;
		findNext();
	}
	
	protected abstract OOPIterator choose(OOPIterator i1, OOPIterator i2);
	
	private void findNext(){
		nextElement = null;
		if (itr1.hasNext() && itr2.hasNext() )
			nextElement = choose(itr1,itr2).next();
		else
			if ( itr1.hasNext() )
				nextElement = itr1.next();
			else if ( itr2.hasNext() )
				nextElement = itr2.next();
	}
	
	public boolean hasNext(){
		return nextElement != null;
	}
	
	public Object next(){
		Object returnMe = nextElement;
		findNext();
		return returnMe;
	}
	
	public Object peek(){
		return nextElement;
	}
	
	public OOPIterator cloneMe(){
		try{
			MergeIterators clone = (MergeIterators)super.clone();
			clone.itr1 = itr1.cloneMe();
			clone.itr2 = itr2.cloneMe();
			return clone;
		}catch(CloneNotSupportedException shouldNotHappen){
			throw new Error("Object claims not to be able to clone");
		}
	}
}