Potential issue

[rrobetti]

In MethodReflectionUtils.java threre is a TODO

//TODO there is a potential issue here, if parameters are received null and more than one method receives the same amount of parameters there is no way to distinguish. Maybe send a Null object with the class type as an attribute and parse it back to null in server is a solution. This situation has not surfaced yet.

Need to review possibilities and see if the issue could really happen? in which scenarios and fix those scenarios.

[petruki]

I checked the interfaces Statement and ResultSet, which are 2 common possible class types that make use of method overload.
They implement similar APIs that can be supplied using either Objects or primitives. In that case, the find method will always return the one that uses Object type as we cannot assign null to primitive arguments.

class MethodReflectionUtilsTest {

	@Test
	void testFindMethodByNameWhenNullParam() throws InvocationTargetException, IllegalAccessException {
		List<Object> params = new ArrayList<>();
		params.add(null);

		Method method = MethodReflectionUtils.findMethodByName(FakeClass.class, "methodA", params);
		FakeClass fakeClass = new FakeClass();

		Boolean result = (Boolean) method.invoke(fakeClass, params.toArray());
		assertTrue(result); // Should invoke methodA(Integer arg1)
		assertTrue(fakeClass.methodA(null)); // Invokes methodA(Integer arg1)
		assertFalse(fakeClass.methodA(1)); // Invokes methodA(int arg1)
	}

	static class FakeClass {
		public boolean methodA(Integer arg1) {
			return true;
		}
		public boolean methodA(int arg1) {
			return false;
		}
	}
}

[rrobetti]

I checked the interfaces Statement and ResultSet, which are 2 common possible class types that make use of method overload. They implement similar APIs that can be supplied using either Objects or primitives. In that case, the find method will always return the one that uses Object type as we cannot assign null to primitive arguments.

class MethodReflectionUtilsTest {

@test
void testFindMethodByNameWhenNullParam() throws InvocationTargetException, IllegalAccessException {
List params = new ArrayList<>();
params.add(null);

  Method method = MethodReflectionUtils.findMethodByName(FakeClass.class, "methodA", params);
  FakeClass fakeClass = new FakeClass();

  Boolean result = (Boolean) method.invoke(fakeClass, params.toArray());
  assertTrue(result); // Should invoke methodA(Integer arg1)
  assertTrue(fakeClass.methodA(null)); // Invokes methodA(Integer arg1)
  assertFalse(fakeClass.methodA(1)); // Invokes methodA(int arg1)

}

static class FakeClass {
public boolean methodA(Integer arg1) {
return true;
}
public boolean methodA(int arg1) {
return false;
}
}
}

@petruki thanks for looking into it, and sorry for the late reply, I am not sure if I understand your idea. The problem with null values is that they don't carry their type so we don't know exactly which method to call, we just have the number of parameters to use in the reflection search, the real trouble might not even be int to Integer but say Integer to Boolean as per if it is just one parameter, it is null and we don't know the type, we cannot infer the sqlType to pass in the setNull(int idx, int sqlType).