Properties should be nullable, use wrapper types not primitives

[joelittlejohn]

Original author: joelittl...@gmail.com (July 06, 2011 23:08:55)

We're currently mapping various schema types to primitive types, which doesn't work well when incoming JSON omits a property altogether. Since Java properties with primitive types are obviously not nullable, we end up with implicit defaults, and no way to distinguish between a value that was omitted and a value that was equal to the primitive default value.

Simple example...

for this schema:
{
"type" : "object",
"properties" : {
"a" : {
"type" : "integer"
}
}
}

we end up with a Java property of type 'int', and hence this data:

{ "a" : 0 }

is indistinguishable from this data:

{}

Clearly this is a significant change to the way POJO generation works (a breaking change in some rare cases where auto-boxing is not enough to keep things happy), hence this is targetted for 0.2.0.

Original issue: http://code.google.com/p/jsonschema2pojo/issues/detail?id=31

[joelittlejohn]

From joelittl...@gmail.com on September 26, 2011 21:01:00
Fix revisions:

r0c6f57738695,
r4b2d6ba9d83e,
r6c1e42d097a9,
rdf0b5c4f7579

Although the default is now to use wrapper types (and support nullable properties), there's now a new behavioural property 'usePrimitives' (--use-primitives or -P for the CLI) to switch to old behaviour and use primitive types.

[joelittlejohn]

From joelittl...@gmail.com on September 26, 2011 21:06:08
Implementation notes:

As part of this change, we've moved away from the behavioural properties 'map of strings' and now have a strongly typed config interface:

com.googlecode.jsonschema2pojo.GenerationConfig

Both the maven plugin and CLI argument object implement this interface, which reduces duplication and adds compile time checking when adding new properties.

For the CLI, we've switched from commons-cli to JCommander. CLI arguments are now expressed via annotations on a config object, which makes implementing the GenerationConfig interface easy in the CLI module.