Code Generation

• It checks whether all calls to methods (in the result pages of other methods) have correct parameter sets. This is important especially for forms. Here the tool checks whether the widgets chosen in each actual parameter matches the type of the corresponding formal parameter.
• It checks wether every link or form declaration is matched by a corresponding called by declaration in the method called.

• For each jsp construct it produces one Java Server Page with the same name.
• For each method within a jsp construct it produces one block in the Java Server Page. This block is executed whenever the appropriate Gently method is called. Within that block it produces code which performs runtime type checking whether the method is called with correct parameters, and converts the parameters to Java local variables with the same name as the formal parameters in the Gently file. Subsequently it creates a protected region which can be used as method body for the Java code.
• For every link or form declaration in the Gently method body it creates HTML code, giving a form or link which offers a correct call to the corresponding method. Within that HTML code, the Gently tool again creates protected regions for each HTML parameter, defining where to insert Java code which produces actual parameters. Of course, the programmer could chose to generate some links with Gently and some other links manually. However, since Gently is not only a generation tool but also a specification language, proper documentation requires that every call to the dialogue methods must be specified within Gently.
• The Gently tool produces comments, structuring the generated code.

• Analyse your dialogue within the notions developed in this chapter.
• Encode the resulting analysis model in Gently. By this you have already achieved a formal specification of your dialogue.
• Invoke the Gently generator and obtain a set of JSP pages. Within these pages, you find protected regions, in which you are allowed to write code. There are two kinds of protected regions offered by Gently: Regions for HTML coding and regions for Java programming.
• Gently facilitates complete separation of HTML coding and Java programming. The generator offers a switch, which triggers generation of separate Java Interfaces. Instead of editing the second kind of protected regions as described above, all Java custom code then has to be provided following the Hollywood Principle.

jsp Cart{
  show(){
       called by redirect  from Cart.changeCart 
    or called by redirect  from Cart.insert 
    or called by redirect  from Cart.insertMany
    or called by viewCart  from Home.welcome
    or called by viewCart  from menu
    and 
       form changeContent calls
            Cart.changeCart(hidden isbn, textfield number) 
    or link buyCart  calls Order.addressForm()
    or link backHome calls Home.welcome()
  }
  changeCart(int[] isbn, int[] number){
       called by changeContent from Cart.show 
    and
       redirect Cart.show()
  }
  insert(int isbn){
       called by toCart from Category.contents
    or called by toCart from Search.results
    and
       redirect Cart.show()
  }
  insertMany(int isbn, int number){
       called by toCart from Singleitem.show
    and 
       redirect  Cart.show()
  }
}

jsp Category{
  contents(String path){
        called by browse      from Home.welcome
     or called by subCategory from Category.contents
     or called by up          from Category.contents
     and 
        // next higher category
        link up calls Category.contents(aParent) 
        // Categories may contain subcategories
     or link subCategory calls Category.contents(aChild) 
        // Categories may contain books 
     or link details calls Singleitem.show(isbn) 
     or link toCart  calls Cart.insert(isbn) 
  }
}

menu{
       link home     calls Home.welcome()
    or link viewCart calls Cart.show()
    or form doSearch calls Search.results(textfield aQuery)
}