diff --git a/src/main/java/io/foldright/inspectablewrappers/utils/WrapperAdapterUtils.java b/src/main/java/io/foldright/inspectablewrappers/utils/WrapperAdapterUtils.java
index ad9b270..e468fce 100644
--- a/src/main/java/io/foldright/inspectablewrappers/utils/WrapperAdapterUtils.java
+++ b/src/main/java/io/foldright/inspectablewrappers/utils/WrapperAdapterUtils.java
@@ -6,20 +6,24 @@
 import io.foldright.inspectablewrappers.Wrapper;
 import io.foldright.inspectablewrappers.WrapperAdapter;
 
+import javax.annotation.ParametersAreNonnullByDefault;
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
 import java.util.Arrays;
+import java.util.concurrent.Callable;
 
+import static io.foldright.inspectablewrappers.utils.WrapperAdapterProxyRelatedMethods.*;
 import static java.util.Objects.requireNonNull;
 
 
 /**
- * Utility class for creating {@link WrapperAdapter} instances
+ * Utility class for creating {@link io.foldright.inspectablewrappers.WrapperAdapter} instances
  * without writing boilerplate code of creating a new adapter class.
  *
  * @author Jerry Lee (oldratlee at gmail dot com)
  */
+@ParametersAreNonnullByDefault
 public final class WrapperAdapterUtils {
     /**
      * Creates a {@link WrapperAdapter} instance of the given biz interface type
@@ -69,12 +73,12 @@ public static <T> T createWrapperAdapter(Class<T> bizInterface, T underlying, T
     @SuppressWarnings({"unchecked", "rawtypes"})
     private static <T> T createWrapperAdapter0(Class<T> bizInterface, T underlying, T adaptee, @Nullable Attachable<?, ?> attachable) {
         final InvocationHandler handler = (proxy, method, args) -> {
-            if (isMethodUnwrap(method)) return underlying;
-            if (isMethodAdaptee(method)) return adaptee;
+            if (UNWRAP.sameSignatureAs(method)) return underlying;
+            if (ADAPTEE.sameSignatureAs(method)) return adaptee;
 
-            if (attachable != null && isMethodGetAttachment(method))
+            if (attachable != null && GET_ATTACHMENT.sameSignatureAs(method))
                 return ((Attachable) attachable).getAttachment(args[0]);
-            if (attachable != null && isMethodSetAttachment(method)) {
+            if (attachable != null && SET_ATTACHMENT.sameSignatureAs(method)) {
                 ((Attachable) attachable).setAttachment(args[0], args[1]);
                 return null;
             }
@@ -90,31 +94,50 @@ private static <T> T createWrapperAdapter0(Class<T> bizInterface, T underlying,
                 handler);
     }
 
-    private static boolean isMethodAdaptee(Method method) {
-        return checkMethod(method, "adaptee");
-    }
-
-    private static boolean isMethodUnwrap(Method method) {
-        return checkMethod(method, "unwrap");
-    }
-
-    private static boolean isMethodGetAttachment(Method method) {
-        return checkMethod(method, "getAttachment", Object.class);
-    }
-
-    private static boolean isMethodSetAttachment(Method method) {
-        return checkMethod(method, "setAttachment", Object.class, Object.class);
-    }
-
-    private static boolean checkMethod(Method method, String methodName, Class<?>... parameterTypes) {
-        return method.getName().equals(methodName)
-                && method.getParameterCount() == parameterTypes.length
-                && Arrays.equals(method.getParameterTypes(), parameterTypes);
-    }
-
     /**
      * NO need to create instance at all
      */
     private WrapperAdapterUtils() {
     }
 }
+
+/**
+ * Use {@code Clazz.class.getMethod(...)} rather than lonely method name constants;
+ * The former is IDE aware, so safer and refactor friendly.
+ */
+enum WrapperAdapterProxyRelatedMethods {
+    /**
+     * {@link WrapperAdapter#adaptee()}
+     */
+    UNWRAP(() -> Wrapper.class.getMethod("unwrap")),
+    /**
+     * {@link Wrapper#unwrap()}
+     */
+    ADAPTEE(() -> WrapperAdapter.class.getMethod("adaptee")),
+    /**
+     * {@link Attachable#getAttachment(Object)}
+     */
+    GET_ATTACHMENT(() -> Attachable.class.getMethod("getAttachment", Object.class)),
+    /**
+     * {@link Attachable#setAttachment(Object, Object)}
+     */
+    SET_ATTACHMENT(() -> Attachable.class.getMethod("setAttachment", Object.class, Object.class)),
+    ;
+
+    private final String methodName;
+    private final Class<?>[] parameterTypes;
+
+    WrapperAdapterProxyRelatedMethods(Callable<Method> method) {
+        try {
+            Method m = method.call();
+            this.methodName = m.getName();
+            this.parameterTypes = m.getParameterTypes();
+        } catch (Exception e) {
+            throw new ExceptionInInitializerError(e);
+        }
+    }
+
+    boolean sameSignatureAs(Method method) {
+        return methodName.equals(method.getName()) && Arrays.equals(parameterTypes, method.getParameterTypes());
+    }
+}