import java.util.*;

public aspect AB {

    static Test unnecessary = new Test();
    static Test cannotTriggerFinal = new Test();
    static Test cannotTriggerFinal2 = new Test();
    static Test canPartiallyTriggerFinal = new Test();
    static Test shadowMotion = new Test();
    static Test shadowMotionRedef = new Test();
    static int x;
    
    tracematch(Object o) {
    	sym a before: call(* *.a()) && target(o);
    	sym b before: call(* *.b()) && target(o);
		sym x before: call(* *.x()) && target(o);

		a+ b
		{
		}
    }

    //all shadows here remain, except the ones tagged
    public static void main(String[] args) {
        unnecessary.b();
        unnecessary.a();
        unnecessary.x();
        unnecessaryShadows1();
        unnecessaryShadows2();
        
        cannotTriggerFinal();
        cannotTriggerFinal2();
        cannotTriggerFinal2.b();//removed by flow-ins
        canTriggerFinal();
        canTriggerFinal2();
        canPartiallyTriggerFinal();
        
        shadowMotion.b();
        shadowMotionRedef.b();
        shadowMotion();
        shadowMotionInnerLoopRedef();
        
        noShadowMotion();
    }
    
    static void unnecessaryShadows1() {
        Test u = unnecessary;
        u.a();//necessary
        u.a();//unnecessary
        u.a();//unnecessary
    }
    
    static void unnecessaryShadows2() {
        Test u = unnecessary;
        u.a();//necessary
        u.a();//unnecessary
        u.a();//unnecessary
        u.b();//necessary
    }
    
    static void cannotTriggerFinal() {
        Test c = cannotTriggerFinal;
        while("".length()>2) {
            c.x();//cannot trigger final
            c.b();//unnecessary
        }
        c.x();//cannot trigger final
    }
    
    static void canTriggerFinal() {
        cannotTriggerFinal.a();//2nd flowins or cannot trigger final, depending on analysis order
    }
    
    static void canTriggerFinal2() {
        cannotTriggerFinal.x();//removed by flowins. only
    }
    
    static void shadowMotion() {
        Test s = shadowMotion;
        while(s.a()) {//moved by sm
            s.x();//removed by sm        
        }
    }
    
    static void shadowMotionInnerLoopRedef() {
        int i = 5;
        while(i>0) {
            Test s = shadowMotionRedef;  //not that s is redefined in the outer loop
            while(s.a()) {//yet... moved by sm
                s.x();//removed by sm        
            }
            i--;
        }
    }

    static void noShadowMotion() {
        Test s = shadowMotion;
        while(s.a()) {//cannot be moved
            s = shadowMotion;//value of shadowMotion might have changed
            s.x();//cannot be moved    
        }
    }

    static class Test {
    
	    boolean a() {return new String().equals("");}
	    void b() {}
	    void x() {}
	    
    }
    
    
}