only check subschema if distinct from schema, and minor changes

Author: eskabetxe

src/main/java/com/networknt/schema/BaseJsonValidator.java

@@ -56,15 +56,16 @@ protected JsonSchema getParentSchema() {
     protected JsonSchema getSubSchema() {
         return subSchema;
     }
-    
+
     protected boolean hasSubSchema() {
         return subSchema != null;
     }
 
     protected JsonSchema obainSubSchemaNode(JsonNode schemaNode){
         JsonNode node = schemaNode.get("id");
         if(node == null) return null;
-    	
+    	if(node.equals(schemaNode.get("$schema"))) return null;
+
         try {
             JsonSchemaFactory factory = new JsonSchemaFactory();
             URL url = new URL(node.textValue());

src/main/java/com/networknt/schema/JsonSchema.java

@@ -62,9 +62,8 @@ public class JsonSchema extends BaseJsonValidator {
      */
     public JsonNode getRefSchemaNode(String ref) {
         JsonSchema schema = findAncestor();
-        JsonNode schemaNode = schema.getSchemaNode();
-        JsonNode node = null;
-        
+        JsonNode node = schema.getSchemaNode();
+
         if (ref.startsWith("#/")) {
             // handle local ref
             String[] keys = ref.substring(2).split("/");
@@ -75,13 +74,16 @@ public JsonNode getRefSchemaNode(String ref) {
                 }
                 Matcher matcher = intPattern.matcher(key);
                 if (matcher.matches()) {
-                    node = schemaNode.get(Integer.parseInt(key));
+                    node = node.get(Integer.parseInt(key));
                 } else {
-                    node = schemaNode.get(key);
+                    node = node.get(key);
                 }
                 if (node == null && schema.hasSubSchema()){
                     node = schema.getSubSchema().getRefSchemaNode(ref);
                 }
+                if (node == null){
+                    break;
+                }
             }
         }
         return node;