Repository navigation
Type dictionary for ListType #437
Description
I'm trying to define some graphQL types dynamically using a typeDefinitionFactory and the fact that field values can be resolved using the Map.get() method. It seems to be working fine as long as I don't have fields with list types. Here's a minimal example of the problem I bumped into:
public static class MyFooType {
public String bar;
}
public static class FooResolver extends HashMap<String, Object> implements GraphQLQueryResolver {
@Override
public Object get(Object key) {
if ("foo".equals(key)) {
return Arrays.asList(new MyFooType(), new MyFooType());
}
throw new IllegalArgumentException("unknown field " + key);
}
}
public static void main(String[] args) {
GraphQLSchema schema =
SchemaParser.newParser().schemaString("""
type Query{ foo: [FooType] }
type FooType { bar: String }
""")
.resolvers(new FooResolver())
.dictionary("FooType", MyFooType.class)
.build().makeExecutableSchema();
System.out.println("OK!");
}This causes an exception:
Exception in thread "main" graphql.kickstart.tools.SchemaClassScannerError: Unable to match type definition (ListType{type=TypeName{name='FooType'}}) with java type (java.lang.Object): Java class is not a List or generic type information was lost: class java.lang.Object
at graphql.kickstart.tools.TypeClassMatcher.error(TypeClassMatcher.kt:20)
at graphql.kickstart.tools.TypeClassMatcher.match(TypeClassMatcher.kt:78)
at graphql.kickstart.tools.TypeClassMatcher.match(TypeClassMatcher.kt:23)
at graphql.kickstart.tools.SchemaClassScanner.scanResolverInfoForPotentialMatches(SchemaClassScanner.kt:257)
...
I guess the problem could be that the framework doesn't know whether to expect a java.util.List or a java array as the foo value. Is there a way to pass this information?
I tried .dictionary("[FooType]", List.class), but that results in another exception:
Exception in thread "main" graphql.kickstart.tools.SchemaClassScannerError: Class in supplied dictionary 'java.util.List' specified type name '[FooType]', but a type definition with that name was not found!
at graphql.kickstart.tools.SchemaClassScanner.<init>(SchemaClassScanner.kt:53)
at graphql.kickstart.tools.SchemaParserBuilder.scan(SchemaParserBuilder.kt:153)
Activity
nnrudakov commentedon Mar 25, 2021
Did you solve it?
mmatela commentedon Jun 2, 2021
Nope, I had to add a wrapper class and declare an accessor method for each
Collection<?>value in the map, lots of boilerplate.oryan-block commentedon Jan 31, 2024
Closing this since it's old but here is a working example anyway:
@Test fun `bing`() { val schema = SchemaParser.newParser() .schemaString( """ type Query{ foo: [FooType] } type FooType { bar: String } """) .resolvers(FooResolver()) .dictionary("FooType", FooType::class.java) .build().makeExecutableSchema() } private class FooResolver : GraphQLQueryResolver { fun foo(): List<FooType> = listOf() } data class FooType(val bar: String = "")