Roger Lee Whitcomb created PIVOT-1047:
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Summary: Make sure that as many listener interfaces as possible
can be used with lambdas
Key: PIVOT-1047
URL: https://issues.apache.org/jira/browse/PIVOT-1047
Project: Pivot
Issue Type: Improvement
Components: core, wtk, wtk-terra
Reporter: Roger Lee Whitcomb
Assignee: Roger Lee Whitcomb
Fix For: 2.1.0
Earlier we had (for Java 8 compatibility) made most/all interfaces implement
default methods so that the Adapter classes could be deprecated. But in working
with these, it appears that defaulting ALL the methods makes them unusable as
lambdas.
For instance, DialogCloseListener has just one interface method, perfect for a
lambda, except with default it isn't eligible. By simply making it pure
abstract there are no negative consequences, and makes it much more useful. By
this I mean, with only one method, the only reason to instantiate one would be
to implement the one, so "default" doesn't really make sense, while
abstract/lambda is perfect.
Investigate this for other interfaces, as some are more problematic, such as
TextInputContentListener, which has multiple "useful" methods, so the trick
would be picking just one (the most commonly implemented one?) to make
abstract. Or ListButtonSelectionListener which has two roughly equally useful
methods, where we would typically use one or the other, but not both. So,
making it lambda-compatible doesn't really help much, in terms of usability.
Others such as Validator are already abstract and need no change, except they
could be marked with the @FunctionalInterface annotation to make this clear.
Careful investigation is needed, since it is possible that making one method
abstract means the Adapter class might not be suitable for Deprecation anymore
either; not sure.
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