[jira] [Closed] (GROOVY-7353) Groovy should provide a MapConstructor AST transform

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

     [ https://issues.apache.org/jira/browse/GROOVY-7353?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Paul King closed GROOVY-7353.
-----------------------------

> Groovy should provide a MapConstructor AST transform
> ----------------------------------------------------
>
>                 Key: GROOVY-7353
>                 URL: https://issues.apache.org/jira/browse/GROOVY-7353
>             Project: Groovy
>          Issue Type: New Feature
>          Components: xforms
>    Affects Versions: 2.4.1
>            Reporter: Paul King
>            Assignee: Paul King
>             Fix For: 2.5.0-alpha-1
>
>
> Groovy supports named-arg style constructor expressions if the object being created contains a Map-based constructor (which currently must be created explicitly) or a no-arg constructor plus appropriate setters. It would be good to have an explicit MapConstructor transform which allowed automatic creation of the Map-based constructor. This is useful for Java integration purposes but also allows various configuration options to be set and better support for final fields.
> Such an AST transform would also potentially allow the Immutable AST transform to be built from components (outside the scope of this issue).
> The transform should work like this:
> {code}
> import groovy.transform.*
> @TupleConstructor
> class Person {
>   String first, last
> }
> @CompileStatic // optional
> @ToString(includeSuperProperties=true)
> @MapConstructor(pre={ super(args?.first, args?.last); args = args ?: [:] }, post = { first = first?.toUpperCase() })
> class Author extends Person {
>   String bookName
> }
> assert new Author(first: 'Dierk', last: 'Koenig', bookName: 'ReGinA').toString() == 'Author(ReGinA, DIERK, Koenig)'
> assert new Author().toString() == 'Author(null, null, null)'
> {code}
> The generated map constructor has a single argument {{args}} of type {{Map}}. In general, you should consider whether you want to guard against NPE exceptions as the above example shows.



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