// We don't have a reference to the selected Product.
// So first we have to lookup the object,
// we do this by a query by example (QBE):
// 1. build an example object with matching primary key values:
Product example = new Product();
example.setId(id);
// 2. build a QueryByIdentity from this sample instance:
Query query = new QueryByIdentity(example);
try
{
// 3. start broker transaction
broker.beginTransaction();
// 4. lookup the product specified by the QBE
Product toBeEdited = (Product) broker.getObjectByQuery(query);
// 5. edit the existing entry
System.out.println("please edit the product entry");
in = readLineWithMessage("enter name (was " + toBeEdited.getName() + "):");
toBeEdited.setName(in);
in = readLineWithMessage("enter price (was " + toBeEdited.getPrice() + "):");
toBeEdited.setPrice(Double.parseDouble(in));
in = readLineWithMessage("enter available stock (was " + toBeEdited.getStock() + "):");
toBeEdited.setStock(Integer.parseInt(in));
// 6. now ask broker to store the edited object
broker.store(toBeEdited);