public BeanBinding(Class<?> beanClass) {
assert !beanClass.isArray() : "Bean is an array: " + beanClass;
assert !beanClass.isPrimitive() : "Bean is primitive type: " + beanClass;
myBeanClass = beanClass;
myTagName = getTagName(beanClass);
assert !StringUtil.isEmptyOrSpaces(myTagName) : "Bean name is empty: " + beanClass;
}
/**
* 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);
}