/**
* Create a default object of the given type. Prefers constructors with as few arguments as
* possible. Creates an empty proxy for interfaces.
*
* @param type type to instantiate
* @return default instance
* @throws Exception if the default instance could not be created
*/
private static Object instantiateType(Class<?> type) throws Exception {
if (type.isPrimitive()) return Defaults.defaultValue(type);
else if (type == Void.class) return null;
else if (type.isArray()) return Array.newInstance(type, 0);
else if (type.isInterface())
return Proxy.newProxyInstance(
type.getClassLoader(),
new Class[] {type},
new InvocationHandler() {
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
return null;
}
});
// Take a constructor with as few params as possible
Constructor constructor = type.getDeclaredConstructors()[0];
for (Constructor<?> c : type.getDeclaredConstructors()) {
if (c.getParameterTypes().length < constructor.getParameterTypes().length) constructor = c;
}
Object[] params = new Object[constructor.getParameterTypes().length];
for (int i = 0; i < constructor.getParameterTypes().length; i++) {
params[i] = instantiateType(constructor.getParameterTypes()[i]);
}
return constructor.newInstance(params);
}
/**
* Create {@link us.ihmc.simulationconstructionset.gui.actions.ActionsTest.MethodCallTester} with
* a proxy object for the given interface that logs all method calls.
*
* @param interfaceClass interface to proxy
* @param forwardInstance interface implementation that will be called when a call is logged (can
* be null)
* @param <T> interface type
* @return method tester instance
*/
private static <T> MethodCallTester<T> createMethodTesterForInterface(
Class<T> interfaceClass, final T forwardInstance) {
final List<MethodInvocation> invocations = new ArrayList<>();
//noinspection unchecked
T mock =
(T)
Proxy.newProxyInstance(
interfaceClass.getClassLoader(),
new Class[] {interfaceClass},
new InvocationHandler() {
@Override
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
invocations.add(new MethodInvocation(method.getName(), args));
if (forwardInstance != null) return method.invoke(forwardInstance, args);
return null;
}
});
return new MethodCallTester<>(mock, interfaceClass, invocations);
}