// if return false the two slots are not equal
// if return true the two slots are equal
private boolean cmpSlot(ObjectSlot objectSlot1, ObjectSlot objectSlot2) {
if (objectSlot1 == null && objectSlot2 == null) {
return true;
}
if ((objectSlot1 != null && objectSlot2 == null)
|| (objectSlot1 == null && objectSlot2 != null)) {
return false;
}
return objectSlot1.equals(objectSlot2);
}
