Add Class-getEnumConstants-instead-of-Enum-values.ql

Author: Marcono1234

codeql-custom-queries-java/queries/recommendations/Class-getEnumConstants-instead-of-Enum-values.ql

@@ -0,0 +1,25 @@
+/**
+ * Finds usage of `Class.getEnumConstants()` called on a type literal, for example
+ * `MyEnum.class.getEnumConstants()`. Such code should be replaced with a call to
+ * the synthetic `values()` method of the enum type, which behaves the same but is
+ * more concise and possibly also slightly faster. For example `MyEnum.values()`.
+ * 
+ * @kind problem
+ */
+
+// Inspired by https://bugs.openjdk.org/browse/JDK-8273140
+
+import java
+
+class GetEnumConstantsMethod extends Method {
+    GetEnumConstantsMethod() {
+        getDeclaringType() instanceof TypeClass
+        and hasName("getEnumConstants")
+    }
+}
+
+from MethodAccess getEnumConstantsCall, EnumType enumType
+where
+    getEnumConstantsCall.getMethod() instanceof GetEnumConstantsMethod
+    and getEnumConstantsCall.getQualifier().(TypeLiteral).getReferencedType() = enumType
+select getEnumConstantsCall, "Should use `" + enumType.getName() + ".values()` instead"