Feature builder for app-schema

[Pushed upstream from internal CSIRO Jira issue created 15/Mar/11. See: https://jira.csiro.au/browse/SISS-1019 (requires login)]

app-schema needs a builder like SimpleFeatureBuilder to aid the programmatic construction of complex features. This might be rather useful to someone working on a complex parser (hint, hint).

-------- Original Message --------
Subject: FeatureBuilder?
Date: Sat, 12 Mar 2011 21:36:00 +0800
From: Jody Garnett
To: Caradoc-Davies, Ben (CESRE, Kensington)

Morning Ben:

I am going through the docs again this weekend; and wondering if your team got around to making a FeatureBuilder? I know we have a SimpleFeatureBuilder in place; but a helper class for app schema content would not be a bad idea?

–
Jody Garnett

-------- Original Message --------
Subject: Re: FeatureBuilder?
Date: Mon, 14 Mar 2011 10:01:00 +0800
From: Ben Caradoc-Davies
To: Jody Garnett

Sorry, no. It is hard to address issues such as polymorphism and feature
type nesting (feature chaining) in a feature builder. It would be great
if we had one, but I recall that there are some rather large hurdles.

Kind regards,
Ben.

-------- Original Message --------
Subject: Re: FeatureBuilder?
Date: Mon, 14 Mar 2011 10:12:49 +0800
From: Jody Garnett
To: Caradoc-Davies, Ben (CESRE, Kensington)

I don't really get that Ben.

If it is hard to address in a builder - how much harder is it to address
with direct use of a factory (with no builder around to help?)

For a FeatureBuildeR:

• polymorphism: this is a association that can have a choice of valid
  (complex?) attributes? For a Feature builder the user is just going to
  supply a value, nobody is saying they have to supply the correct one.
• feature type nesting: for a feature they are going to choose a single
  feature type to fill in, the fact that feature type is defined in
  relation to its super types is neither here nor there (and we have some
  utility functions to produce a list of everything at the end of the day
  which should help)

For a FeatureTypeBuilder:

• polymorphism: This should be easier to help out; when defining the
  association you can supply one or more complex types that are valid
  targets? (I assume that each complex type referenced would be created
  independently before hand).
• feature type nesting: Same deal as above, create the super feature
  type before hand and you can just refer to it when defining your sub type.

Although it does give me a good idea, an alternative to "build" which
would both build the current type, and fill in the current type as
"super" to allow definition of nested types quickly.

build.setName("Foo");
build.add("field", String.class );
build.super();
build.setName("Bar");
build.add("field2", String.class );

How are you writing test cases for app schema? Do you build the features
and types by hand using the factories?

–
Jody Garnett

-------- Original Message --------
Subject: factory / builder fun
Date: Mon, 14 Mar 2011 11:13:05 +0800
From: Jody Garnett
To: Caradoc-Davies, Ben (CESRE, Kensington)

Hi Ben

Reading my email and was worried it came across as harsh Since I
plan to use the feature model I would like it to work; if you did have
any interest into what made it difficult it would be a good thing to learn.

I was really hoping your team would pick up that ball and throw the
feature model around and clean it up and make it easy to use. I
understand that appschema has been really tough. I have appreciated the
hard work Niels has put in recently.

On a related note we still have an issue with FeatureCollection to sort
out (with respect to publishing the descriptor of the members rather
than simply their type).

–
Jody Garnett