StringBuffer s = new StringBuffer();
Enumeration e = _expressions.keys();
while(e.hasMoreElements())
{
ExpressionKey key = (ExpressionKey)e.nextElement();
Expression exp = (Expression)_expressions.get(key);
s.append(exp.getClass().getName() + ", " + System.identityHashCode(exp) + ", ");
for (int i = 0; i < key.args().length; i++)
{
if(i!=0) s.append(", ");
Object o = key.args()[i];
if(o instanceof Number)