[jira] [Updated] (GROOVY-7427) TupleConstructor should allow a mechanism to switch off automatic parameter defaults

["Paul King (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/GROOVY-7427?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Paul King updated GROOVY-7427:
------------------------------
    Component/s: xforms

> 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
>          Components: xforms
>            Reporter: Paul King
>            Assignee: Paul King
>            Priority: Minor
>             Fix For: 2.5.0-beta-1
>
>
> 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.



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