Add lossless narrowing convertion (#379)

Author: hkupty

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

@@ -42,6 +42,11 @@ public class SchemaValidatorsConfig {
      */
     private boolean javaSemantics;
 
+    /**
+     * When set to true, can interpret round doubles as integers
+     */
+    private boolean losslessNarrowing;
+
     /**
      * Map of public, normally internet accessible schema URLs to alternate locations; this allows for offline
      * validation of schemas that refer to public URLs. This is merged with any mappings the {@link JsonSchemaFactory}
@@ -192,5 +197,12 @@ public CollectorContext getCollectorContext() {
     public void setCollectorContext(CollectorContext collectorContext) {
         this.collectorContext = collectorContext;
     }
-	
+
+    public boolean isLosslessNarrowing() {
+        return losslessNarrowing;
+    }
+
+    public void setLosslessNarrowing(boolean losslessNarrowing) {
+        this.losslessNarrowing = losslessNarrowing;
+    }
 }

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

@@ -74,6 +74,8 @@ public static JsonType getValueNodeType(JsonNode node, SchemaValidatorsConfig co
             if (node.isNumber())
                 if (config.isJavaSemantics() && node.canConvertToLong() && (node.asText().indexOf('.') == -1))
                     return JsonType.INTEGER;
+                else if (config.isLosslessNarrowing() && node.asText().endsWith(".0"))
+                    return JsonType.INTEGER;
                 else
                     return JsonType.NUMBER;
             if (node.isBoolean())

src/test/java/com/networknt/schema/TypeFactoryTest.java

@@ -50,4 +50,24 @@ public void testValidIntegralValuesWithoutJavaSemantics() {
                     getValueNodeType(DecimalNode.valueOf(new BigDecimal(validValue)), schemaValidatorsConfig));
         }
     }
+
+    @Test
+    public void testWithLosslessNarrowing() {
+        schemaValidatorsConfig.setLosslessNarrowing(true);
+            assertSame(validValue, JsonType.INTEGER,
+                    getValueNodeType(DecimalNode.valueOf(new BigDecimal("1.0")), schemaValidatorsConfig));
+
+            assertSame(validValue, JsonType.NUMBER,
+                getValueNodeType(DecimalNode.valueOf(new BigDecimal("1.5")), schemaValidatorsConfig));
+    }
+
+    @Test
+    public void testWithoutLosslessNarrowing() {
+        schemaValidatorsConfig.setLosslessNarrowing(false);
+        assertSame(validValue, JsonType.NUMBER,
+                getValueNodeType(DecimalNode.valueOf(new BigDecimal("1.0")), schemaValidatorsConfig));
+
+        assertSame(validValue, JsonType.NUMBER,
+                getValueNodeType(DecimalNode.valueOf(new BigDecimal("1.5")), schemaValidatorsConfig));
+    }
 }