title: Equal of xsi:type in JSON Schema
body: <p>How can I hint the type of embedded objects in <a href="http://json-schema.org/latest/json-schema-validation.html" rel="nofollow">JSON Schema</a>, analogous to <code>xsi:type</code> in XML Schema?</p>
  
  <p><strong>Example</strong> schema document:</p>
  
  <pre><code>{
      "type": "storeRequest",
      "properties": {
          "txid": {
              "description": "Transaction ID to prevent double committing",
              "type": "integer"
          },
          "objects": {
              "description": "Objects to store",
              "type": "array"
              "items": {
                  "type": "object"
              },
              "minItems": 1,
              "uniqueItems": true
          },
      },
      "required": ["txid", "objects"]
  }
  </code></pre>
  
  <p>This is a request the client sends to the server to store multiple objects in the database. Now how can I recursively validate the content of <strong>objects</strong> when it can contain more than one type of object. (Plymorphism, really).</p>