Paul King created GROOVY-7427:
---------------------------------
Summary: TupleConstructor should allow a mechanism to switch off
automatic parameter defaults
Key: GROOVY-7427
URL: https://issues.apache.org/jira/browse/GROOVY-7427
Project: Groovy
Issue Type: Improvement
Reporter: Paul King
Assignee: Paul King
Priority: Minor
When using @TupleConstructor, it automatically provides defaults for the
parameters. This is particularly useful behavior since it allows parameters
which can remain as their default (user provided or null/0/false) can be left
out of the constructor. In particular, a no-arg constructor corresponds to the
case of all arguments left out. This is exactly the kind of constructor which
Groovy needs for default named-argument processing.
Having said that, there are times when all is required is a single simple
constructor having all of the classes properties. This issue allows a parameter
{{defaults=false}} to be set to enable this new behavior.
For this class:
{code}
@TupleConstructor
class Person {
String first, last
int age
}
{code}
The following normal constructor is produced:
{code}
Person(String first=null, String last=null, int age=0) { this.first = first
//etc... }
{code}
After Groovy's compilation phases are complete, the following constructors are
visible to Java:
{code}
Person(String first, String last, int age) { //... }
Person(String first, String last) { this(first, last, 0) }
Person(String first) { this(first, null) }
Person() { this(null) }
{code}
Adding {{defaults=false}} as a parameter to TupleConstructor means that just
the first of these will be produced. If any of the properties has a default
value, when this setting is made false, an error will be flagged.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
