import gov.nasa.jpf.JPFListener;
import gov.nasa.jpf.ListenerAdapter;
import gov.nasa.jpf.search.Search;

public class StateSpace extends ListenerAdapter implements JPFListener 
{
	private int previous;
	
	public StateSpace() 
	{
		this.previous = -1;
	}
	
	public void stateAdvanced(Search search) 
	{
		int current = search.getStateId();
		if (this.previous != -1) 
		{
			System.out.printf("%d -> %d%n", this.previous, current);
		}
		this.previous = current;
	}
	
	public void stateBacktracked(Search search) 
	{
		this.previous = search.getStateId();
	}
	
	public void stateRestored(Search search) 
	{
		this.previous = search.getStateId();
	}
}