How to set a default custom schema for types in Swagger

Question

There is a way to define a custom schema as default for a Java Class in Swagger?

You can set the schema with annotations like this:

schema = @Schema(type = "string", format = "<custom-format>", example = "<custom-example>"))

But I want to assign this schema to a Java Class as default, so I don't need to add schema annotations always I define this data type on API.

• https://swagger.io/docs/specification/data-models/data-types/
• https://github.com/swagger-api/swagger-core/wiki/Swagger-2.X---Annotations#schema

---

Update

Default schema types are defined in https://github.com/swagger-api/swagger-core/blob/master/modules/swagger-core/src/main/java/io/swagger/v3/core/util/PrimitiveType.java

There is a way to override or extend this?

Answer 1

1. Create a custom ModelConverter:

import java.lang.reflect.Type;
import java.time.YearMonth;
import java.util.Iterator;

import com.fasterxml.jackson.databind.type.SimpleType;

import io.swagger.v3.core.converter.AnnotatedType;
import io.swagger.v3.core.converter.ModelConverter;
import io.swagger.v3.core.converter.ModelConverterContext;
import io.swagger.v3.oas.models.media.Schema;

/*
* Custom ModelConverter that create a custom schema for YearMonth types
*/
public class CustomModelConverter implements ModelConverter {
    private static final Schema SCHEMA_YEAR_MONTH = new Schema().type("string").format("year-month").example("2020-06");

    @Override
    public Schema resolve(AnnotatedType annotatedType, ModelConverterContext context, Iterator<ModelConverter> chain) {
        Type type = annotatedType.getType();
        if (type instanceof SimpleType) {
            SimpleType simpleType = (SimpleType) type;

            if (YearMonth.class.isAssignableFrom(simpleType.getRawClass())) {
                return SCHEMA_YEAR_MONTH;
            }
        }

        // It's needed to follow chain for unresolved types
        if (chain.hasNext()) {
            return chain.next().resolve(annotatedType, context, chain);
        }
        return null;
    }
}

2. Register your custom ModelConverter:

ModelConverters.getInstance().addConverter(new CustomModelConverter());

Suggestion: put this as static initializer block on JAX-RS Activator