adding ValidatingVisitor#passesTypeCheck()

This method handles the possible combinations of the Schema#requires* methods and the nullable flag

It is currently only used by ObjectSchema

Also removing unused ValidatingVisitor ctor.

Author: erosb

core/src/main/java/org/everit/json/schema/ObjectSchemaValidatingVisitor.java

@@ -28,11 +28,7 @@ public ObjectSchemaValidatingVisitor(Object subject, ValidatingVisitor owner) {
     }
 
     @Override void visitObjectSchema(ObjectSchema objectSchema) {
-        if (!(subject instanceof JSONObject)) {
-            if (objectSchema.requiresObject()) {
-                owner.failure(JSONObject.class, subject);
-            }
-        } else {
+        if (owner.passesTypeCheck(JSONObject.class, objectSchema.requiresObject(), objectSchema.isNullable())) {
             objSubject = (JSONObject) subject;
             objectSize = objSubject.length();
             this.schema = objectSchema;

core/src/main/java/org/everit/json/schema/StringSchemaValidatingVisitor.java

@@ -61,4 +61,5 @@ public StringSchemaValidatingVisitor(Object subject, ValidationFailureReporter f
             failureReporter.failure(failure.get(), "format");
         }
     }
+
 }

core/src/main/java/org/everit/json/schema/ValidatingVisitor.java

@@ -19,11 +19,6 @@ private static boolean isNull(Object obj) {
 
     private ValidationFailureReporter failureReporter;
 
-    ValidatingVisitor(Schema schema, Object subject) {
-        this.subject = subject;
-        this.failureReporter = new CollectingFailureReporter(schema);
-    }
-
     @Override
     void visit(Schema schema) {
         if (schema.isNullable() == Boolean.FALSE && isNull(subject)) {
@@ -156,4 +151,19 @@ void failure(ValidationException exc) {
         failureReporter.failure(exc);
     }
 
+    boolean passesTypeCheck(Class<?> expectedType, boolean schemaRequiresType, Boolean nullable) {
+        if (isNull(subject)) {
+            if (schemaRequiresType && nullable != Boolean.TRUE) {
+                failureReporter.failure(expectedType, subject);
+            }
+            return false;
+        }
+        if (expectedType.isAssignableFrom(subject.getClass())) {
+            return true;
+        }
+        if (schemaRequiresType) {
+            failureReporter.failure(expectedType, subject);
+        }
+        return false;
+    }
 }

core/src/test/java/org/everit/json/schema/ObjectSchemaTest.java

@@ -439,4 +439,9 @@ public void emptyObjectPropertyNamesSchema() {
 
         subject.validate(new JSONObject("{}"));
     }
+
+    @Test
+    public void requiresObject_stillNullable() {
+        ObjectSchema.builder().requiresObject(true).nullable(true).build().validate(JSONObject.NULL);
+    }
 }