Added readme

Jackson jsonSchema Generator

===================================

This projects aims to do a better job than the original [jackson-module-jsonSchema](https://github.com/FasterXML/jackson-module-jsonSchema)

in generating jsonSchema from your POJOs using Jackson @Annotations.

**Highlights**

* JSON Schema Draft v4

* Supports polymorphism using **@JsonTypeInfo** and **oneOf**

**Benefits**

* Simple implementation - Just [one file](https://github.com/mbknor/mbknor-jackson-jsonSchema/blob/master/src/main/scala/com/kjetland/jackson/jsonSchema/JsonSchemaGenerator.scala)  (for now..) 

* Implemented in Scala 

* Easy to fix and add functionality

**The Future**

* Should support all different variations of Jackson-usage

* Should support all (a lot?) of *javax.validation-API* 

Project status

---------------

We're currently using this codebase in an ongoing (not yet released) project at work,

and we're improving the jsonSchema-generating code when we finds issues and/or features we need that not yet is supported.

**Currently missing**

* Good tests

* Lot of javax.validation-API support

* Some jackson-/jsonSchema-features (Stuff we're not using)

I would really appreciate it if other developers wanted to start using and contributing improvements and features. 

Dependency

===================

The project is currently not published to any repo yet, so you have to clone it and build it your self using sbt.

Using Maven

-----------------

Build is using sbt:

    sbt publishM2 

Add this to you pom.xml:

    <dependency>

        <groupId>com.kjetland</groupId>

        <artifactId>mbknor-jackson-jsonschema_2.11</artifactId>

        <version><!-- INSERT VERSiON HERE --></version>

    </dependency>    

Using sbt

------------

Build is using sbt:

    sbt publish 

Add this to you sbt build-config:

    "com.kjetland" % "mbknor-jackson-jsonschema" %% <!-- INSERT VERSiON HERE -->

Code

-------------------------------

This is how to generate jsonSchema in code using Scala:

    val objectMapper = new ObjectMapper

    val jsonSchemaGenerator = new JsonSchemaGenerator(objectMapper)

    val jsonSchema:JsonNode = jsonSchemaGenerator.generateJsonSchema(classOf[YourPOJO])

    val jsonSchemaAsString:String = objectMapper.writeValueAsString(jsonSchema)

And using Java:

    ObjectMapper objectMapper = new ObjectMapper();

    JsonSchemaGenerator jsonSchemaGenerator = new JsonSchemaGenerator(objectMapper);

    JsonNode jsonSchema = jsonSchemaGenerator.generateJsonSchema(YourPOJO.class);

    String jsonSchemaAsString = objectMapper.writeValueAsString(jsonSchema);

Backstory

--------------

At work we've been using the original [jackson-module-jsonSchema](https://github.com/FasterXML/jackson-module-jsonSchema) 

to generate schemas used when rendering dynamic GUI using [https://github.com/jdorn/json-editor](https://github.com/jdorn/json-editor).

Recently we needed to support POJO's using polymorphism like this:

    @JsonTypeInfo(

            use = JsonTypeInfo.Id.NAME,

            include = JsonTypeInfo.As.PROPERTY,

            property = "type")

    @JsonSubTypes({

            @JsonSubTypes.Type(value = Child1.class, name = "child1"),

            @JsonSubTypes.Type(value = Child2.class, name = "child2") })

    public abstract class Parent {

        public String parentString;

    }

This is not supported by the original [jackson-module-jsonSchema](https://github.com/FasterXML/jackson-module-jsonSchema).

I have spent many hours trying to figure out how to modify/improve it without any luck,

and since it is implemented in such a complicated way, I decided to instead write my own

jsonSchema generator from scratch.