Java Reference
In-Depth Information
If there are errors, the user is redirected to the
create()
action. For this redirect to the
create()
action, params was assigned to the
bookInstance
's property, as mentioned in the
create()
action
earlier in Listing 7-20. If there are no errors, the show view is rendered with the newly created
instance.
Show Action
Listing 7-22 illustrates the
show()
action of the
BookController
.
Listing 7-22. The Show Action of the BookController
def show(Long id) {
def bookInstance = Book.get(id)
if (!bookInstance) {
flash.message = message(code: 'default.not.found.message',
args: [message(code: 'book.label', default: 'Book'), id])
redirect(action: "list")
return
}
[bookInstance: bookInstance]
}
The
show()
action expects an
id
parameter. The first line of the
show()
action calls the
Book.get( )
method to retrieve the
Book
referred to by the
id
parameter. If no
Book
instance exists with the
id
passed in, an error message is stored in the flash scope, and the user is redirected to the list view.
If a
Book
instance is found with the
id
passed in, it is returned in a Map with the key of
bookInstance
,
and the
show()
action will render the show view.
Edit Action
Listing 7-23 illustrates the
edit()
action of the
BookController
.
Listing 7-23. The Edit Action of the BookController
def edit(Long id) {
def bookInstance = Book.get(id)
if (!bookInstance) {
flash.message = message(code: 'default.not.found.message', args: [message(code: 'book.
label', default: 'Book'), id])
redirect(action: "list")
return
}
[bookInstance: bookInstance]
}
The
edit()
action loads the necessary data that will be used during editing and passes it to the edit
view. The
edit()
action is very much the same as the
show()
action. The name of the
edit()
action,
edit
, is used to render the edit view.
