[booking example]: question regarding the HotelBookingAction

[ellenzhao]

The code in question:

@In(required=false)
@Out(required=false)
private Booking booking;

I thought a booking without a Booking instance sounds weird, so that I removed the (required=false) for the @In annotation. But then got an org.jboss.seam.RequiredException. But in the RegisterAction.java, there is

@In
private User user;

And it works. I looked for the more precise explanation about the "required" attribute, but the documentation didn't answer my question: Required from what? Required for what? (I thought a Booking instance should be required for a booking action, logically. But it seems that it is "required" from the context.... I changed the annotation to @In (create = true) and it worked again, but I guess the created instance would soon be an orphan in the heap since there is this line:

booking = new Booking(hotel, user);

in the bookHotel() method. )

More changes I made to the code: after user login, the pageflow is managed by a jpdl file.

[pmuir]

The required attribute on @In/@Out simply says whether the variable can be null or not, by default required=true.

so, lets say we have a variable foo.

If the context variable foo is null

@In Foo foo;

would throw a RequiredException

but

@In(required=true) Foo foo;

wouldn't.

But, if the context variable foo is not null

neither

@In Foo foo;

nor

@In(required=true) Foo foo;

would throw a RequiredException.

If you are using out, its the instance variable, not the context variable that is not null.

If create=true then, if the context variable is null, Seam attempts to create it (@Name or @Factory), if it can't, and required=true, then a RequiredException will be thrown.

[ellenzhao]

"petemuir" wrote:
The required attribute on @In/@Out simply says whether the variable can be null or not, by default required=true.

so, lets say we have a variable foo.

If the context variable foo is null

@In Foo foo;

would throw a RequiredException

but

@In(required=true) Foo foo;

wouldn't.

Was there a typo? It might be

@In(required = false) Foo foo;

or?

[pmuir]

Sorry, yes, a typo ;)