package tracematches;

import java.util.*;

public class HasNextElem {
	
	static aspect HashNextElemCheck{
		
		tracematch(Enumeration e) {
			sym hasNext before : call(boolean Enumeration.hasMoreElements()) && target(e);
			sym next before : call(Object Enumeration.nextElement()) && target(e);

			next next
			{
				if(System.getProperty("TMTEST_ACTIVE")!=null) {
				     throw new RuntimeException("Should call 'boolean Enumeration.hasMoreElements()'");
				}
			}
		}

	}
	
	public static void main(String[] args) {
		
		//unsafe
		Vector c = new Vector();
		c.add("");
		c.add("");
		Enumeration e = c.elements();
		System.out.println("n1");
		e.nextElement();
		e.hasMoreElements();
		System.out.println("n2");
		e.nextElement();
		System.out.println("n3");
		e.nextElement();
		
		//safe but not detected as such (needs must-point-to info) 
		Vector c2 = new Vector();
		Enumeration e2 = c2.elements();
		while(e2.hasMoreElements()) {
			e2.nextElement();			
		}
		
		
	}
			
}