Ion Schema Kotlin

A reference implementation of the Ion Schema Specification, written in Kotlin.

Getting Started

The following kotlin and java code samples are a simple example of how to use this API. The Customer type is a struct that requires firstName and lastName fields as strings, while the middleName field is optional ( To keep things simple, the schema is loaded inline ).

Kotlin

import com.amazon.ion.system.IonSystemBuilder
import com.amazon.ionschema.IonSchemaSystemBuilder.Companion.standard
import com.amazon.ionschema.Type


object IonSchemaGettingStarted {
    private val ION = IonSystemBuilder.standard().build()
    @JvmStatic
    fun main(args: Array<String>) {
        val iss = standard()
                .build()

        val schema = iss.newSchema(
                """
            type::{
              name: Customer,
              type: struct,
              fields: {
                firstName: { type: string, occurs: required },
                middleName: string,
                lastName: { type: string, occurs: required },
              },
            }
        """
        )
        val type = schema.getType("Customer")
        checkValue(type, """ { firstName: "Susie", lastName: "Smith" } """)
        checkValue(type, """ { firstName: "Susie", middleName: "B", lastName: "Smith" } """)
        checkValue(type, """ { middleName: B, lastName: Washington } """)
    }

    private fun checkValue(type: Type?, str: String) {
        val value = ION.singleValue(str)
        val violations = type!!.validate(value)
        if (!violations.isValid()) {
            println(str)
            println(violations)
        }
    }
}

Java

import com.amazon.ion.IonSystem;
import com.amazon.ion.IonValue;
import com.amazon.ion.system.IonSystemBuilder;
import com.amazon.ionschema.AuthorityFilesystem;
import com.amazon.ionschema.IonSchemaSystem;
import com.amazon.ionschema.IonSchemaSystemBuilder;
import com.amazon.ionschema.Schema;
import com.amazon.ionschema.Type;
import com.amazon.ionschema.Violations;

public class IonSchemaGettingStarted {
    private static IonSystem ION = IonSystemBuilder.standard().build();

    public static void main(String[] args) {
        IonSchemaSystem iss = IonSchemaSystemBuilder.standard()
                .build();

        Schema schema = iss.newSchema(" type::{\n" +
                        "              name: Customer,\n" +
                        "              type: struct,\n" +
                        "              fields: {\n" +
                        "                firstName: { type: string, occurs: required },\n" +
                        "                middleName: string,\n" +
                        "                lastName: { type: string, occurs: required },\n" +
                        "              },\n" +
                        "            }\n")
                ;
        Type type = schema.getType("Customer");

        checkValue(type, "{ firstName: \"Susie\", lastName: \"Smith\" }");
        checkValue(type, "{ firstName: \"Susie\", middleName: \"B\", lastName: \"Smith\" }");
        checkValue(type, "{ middleName: B, lastName: Washington }");
    }

    private static void checkValue(Type type, String str) {
        IonValue value = ION.singleValue(str);
        Violations violations = type.validate(value);
        if (!violations.isValid()) {
            System.out.println(str);
            System.out.println(violations);
        }
    }
}

When run, the code above produces the following output:

{ middleName: B, lastName: Washington }
Validation failed:
- one or more fields don't match expectations
  - firstName
    - expected range::[1,1] occurrences, found 0
  - middleName: B
    - expected type string, found symbol
  - lastName: Washington
    - expected type string, found symbol

Development

This repository contains two git submodules: ion-schema-tests and ion-schema-schemas. Both are used by this library's unit tests.

The easiest way to clone the ion-schema-kotlin repository and initialize its submodules is to run the following command:

$ git clone --recursive https://github.com/amzn/ion-schema-kotlin.git ion-schema-kotlin

Alternatively, the submodule may be initialized independently from the clone by running the following commands:

$ git submodule init
$ git submodule update

ion-schema-kotlin may now be built with the following command:

$ gradle build

Pulling in Upstream Changes

To pull upstream changes into ion-schema-kotlin, start with a simple git pull. This will pull in any changes to ion-schema-kotlin itself (including any changes to its .gitmodules file), but not any changes to the submodules. To make sure the submodules are up-to-date, use the following command:

$ git submodule update --remote

For detailed walkthroughs of git submodule usage, see the Git Tools documentation.

Roadmap

The roadmap is organized as a series of milestones.

License

This library is licensed under the Apache 2.0 License.