[
    {
        "schema" : {
            "$schema": "http://json-schema.org/draft-04/schema#",

            "definitions": {
                "address": {
                    "type": "object",
                    "properties": {
                        "street_address": { "type": "string" },
                        "city":           { "type": "string" },
                        "state":          { "type": "string" }
                    },
                    "required": ["street_address", "city", "state"]
                }
            },

            "type": "object",

            "properties": {
                "billing_address": { "$ref": "#/definitions/address" },
                "shipping_address": {
                    "allOf": [
                        { "$ref": "#/definitions/address" },
                        { "properties":
                        { "type": { "enum": [ "residential", "business" ] } },
                            "required": ["type"]
                        }
                    ]
                }
            }
        }
    }]