Ordering of properties within a HAL forms template

[smcgregor83]

I am playing around with the new HAL forms functionality and I have a question. It appears that properties within the affordance templates are being sorted alphabetically losing the order specified on the POJO. I presume this will be by design.

My goal is to create a client which renders dynamic forms based on the response from the API but I would want to be able to control ordering from the server. A simple workaround I can see is a prefix on the name of the field (i.e. field1_firstName, field2_lastName, field3_email).

Is there a recommended approach for doing this? Is it possible to retain the order of the properties as defined in the POJO?

[gregturn]

While I sympathize with your desire to control the order of properties on an HTML form, it appears that the code that retrieves properties of a POJO are found in the Spring Framework (BeanUtils. getPropertyDescriptors):

spring-hateoas/src/main/java/org/springframework/hateoas/mediatype/PropertyUtils.java

Lines 201 to 208 in fc1b4a8

	private static Stream<PropertyDescriptor> getPropertyDescriptors(Class<?> type) {
	return Arrays.stream(BeanUtils.getPropertyDescriptors(type))
	.filter(descriptor -> !FIELDS_TO_IGNORE.contains(descriptor.getName()))
	.filter(descriptor -> !descriptorToBeIgnoredByJackson(type, descriptor))
	.filter(descriptor -> !toBeIgnoredByJackson(type, descriptor.getName()))
	.filter(descriptor -> !readerIsNotToBeIgnoredByJackson(descriptor));
	}

There is no form of sorting done inside Spring HATEOAS, so I don't see how to affect any changes.

[odrotbohm]

I wonder if HalFormsConfiguration could expose API to help define the order, either through some configuration callback or an explicit ordering call ….withFieldOrderFor(Foo.class, "firstname", "lastname". Making use of the field declaration order is quite involved as it would require us to use ASM to scan the class' bytecode.

In general any kind of reflection lookup of properties does not regard any declaration orders as in the reflection API methods do not guarantee any order of the results at all.

[gregturn]

With options for a “strict” mode that ONLY applies to the specified type, and perhaps an “inherited” mode that does an instanceof check?