Proposal: Deprecate Builders

Eva Krejcirova eva.krejcirova at oracle.com
Tue Mar 26 08:49:17 PDT 2013


Hi,

I'd like to add some more info for anybody who is interested in what 
problems we are facing with builders:

We currently have two major problems with builders:

* the create() method (RT-24272) *
It's not possible to call the create() method for generic builders and 
the current attempt to solve this doesn't handle builders creating 
generic classes themselves.
e.g. trying to compile TableView<String> tableView1 = 
TableViewBuilder.<String>create();
results in
"reference to create is ambiguous, both method create() in 
javafx.scene.layout.RegionBuilder and method <S>create() in 
javafx.scene.control.TableViewBuilder match"

It was possible up until Java 7 because of some bugs in JDK 6, which 
were now fixed. Currently, the builders compile, but it's not possible 
to compile a user code which tries to call such create() method. It's 
possible that in the future the builders themselves won't even compile 
when more bugs in javac are fixed.
This problem is actually present even in JavaFX 2.2 with Java 7 (in 
builders for charts).
This also means that if we just move the builders in separate jar file 
in the state they are now (or were in 2.2), some of them will be unusable.

(Actually in current code we have half-baked attempt to solve this 
(added TableView.create(Class<?>))  so you can call create() for some 
cases, but it's not a real solution as it doesn't work for all cases)

* binary incompatibilities when moving methods to superclass in scenegraph *
When we move some method to superclass in the scenegraph hierarchy 
(let's say change Shape.fill() to Node.fill()) this is OK for the 
classes in scenegraph. However, since the builder methods return generic 
type, this creates binary incompatibility in builders. Currently, we 
solve such incompatibilities manually (e.g. RT-24540) which is extremely 
error prone.

More info can be found in https://javafx-jira.kenai.com/browse/RT-24272

Regards,
Eva




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