Workshop 201, Tutorial 3, Step 2, Apex

InvoiceUtilities.cls

public class InvoiceUtilities {

    // class method to renumber Line Items for a given Invoice number
    // returns a string that indicates success or failure
    public static String renumberLineItems(String invoiceName) {

    // create a copy of the target Invoice object and it's Line Items

    // loop through each Line Item, renumbering as you go

    // update the Line Items in one transaction, rollback if any problems
    // and return error messages to the calling environment

    // on success, return the list to the calling program
  }
}