package tracematches;

import java.util.*;

public aspect HashMapTest {
    
  /**
  * This version is better in a way that it checks if the modification really changed the hash code
  * of the collection in question. Also it works for arbitrary objects, not just collections.
  * BUT it uses let().
  */
 tracematch(HashMap s, Object o, int hashCode) {
     
     sym add before : call(* HashMap.put(Object,*)) && target(s) && args(o,*) && let(hashCode, o.hashCode());
     sym remove before : call(* HashMap.remove(Object)) && target(s) && args(o);
     sym cont before: call(* HashMap.contai*(..)) && target(s) && args(o);

 	 //check after each remove and after each "contains" but only if the object was not removed before
     add cont* remove | add cont {

		if(hashCode!=o.hashCode()) {    
			if(System.getProperty("TMTEST_ACTIVE")!=null) {
		             System.out.println("HashCode changed for Object "+o+" while being in a HashSet.");
			}
		 } 

     }
 }
 
    
}


class RealTest {
    
    public static void main(String[] args) {
        HashMap m = new HashMap();        
        Collection c = new ArrayList();
        Object value = new Object();
        
        //safe but not detectable (need must-point-to info)
        m.put(c,value);
        m.remove(c);
        System.out.println("allowed modification");
        c.add("allowed modification");
        System.out.println(m.containsKey(c));
        c.clear();
        
        //unsafe
        m.put(c,value);
        System.out.println("this should trigger an error");
        c.add("this should trigger an error");
        System.out.println(m.containsKey(c));

        //safe
        Collection c2 = new ArrayList();
        m.containsKey(c2);
        
        //safe
        HashMap m2 = new HashMap();        
        m2.containsKey(c);
        
    }
    
}