[Java] how to extract all field name which type is String ?

[hxzhao527]

hi. I try to use ast-grep to parse some Java code. But it fails me.

@Component
class ABC extends Object{
    @Resource
    private final String with_anno;

    private final String with_multi_mod;

    public String simple;
}

I want to extract all field name which type is String, I tried

rule:
  pattern:
    selector: field_declaration
    context: class A{ String $F;}

but it match nothing. it requires a precise modifier , even context: class A{ $MOD String $F;} not work.

rule:
  pattern:
    selector: field_declaration
    context: class A{ private String $F;}

this rule will match private final String with_multi_mod;. but I don't want to enumerate all modifiers.

so my question is: how to extract all field name which type is String?

[HerringtonDarkholme]

You can use kind + has

https://ast-grep.github.io/playground.html#eyJtb2RlIjoiQ29uZmlnIiwibGFuZyI6ImphdmEiLCJxdWVyeSI6ImAkVEFHYCIsInJld3JpdGUiOiIiLCJzdHJpY3RuZXNzIjoic21hcnQiLCJzZWxlY3RvciI6IiIsImNvbmZpZyI6InJ1bGU6XG4gIGtpbmQ6IGZpZWxkX2RlY2xhcmF0aW9uXG4gIGhhczpcbiAgICBmaWVsZDogdHlwZVxuICAgIHJlZ2V4OiBeU3RyaW5nJCIsInNvdXJjZSI6IkBDb21wb25lbnRcbmNsYXNzIEFCQyBleHRlbmRzIE9iamVjdHtcbiAgICBAUmVzb3VyY2VcbiAgICBwcml2YXRlIGZpbmFsIFN0cmluZyB3aXRoX2Fubm87XG5cbiAgICBwcml2YXRlIGZpbmFsIFN0cmluZyB3aXRoX211bHRpX21vZDtcblxuICAgIHB1YmxpYyBTdHJpbmcgc2ltcGxlO1xufSJ9

rule:
  kind: field_declaration
  has:
    field: type
    regex: ^String$

[hxzhao527]

it works, although without meta var. thanks.

[HerringtonDarkholme]

you can further use all and has to decompose meta variable

[hxzhao527]

second question: why this rule not work?

rule:
  pattern:
    selector: field_declaration
    context: class A{ $MOD String $F;}

[HerringtonDarkholme]