kaphein-java-may-be-value

An anternative to java.util.Optional to represent optional fields in classes.

MayBeValue is a container object which may or may not contain a nullable value.

Unlike java.util.Optional, the value described by a MayBeValue instance can be null. An empty MayBeValue instance represents that there is NEITHER non-null value nor null in the MayBeValue instance.

MayBeValue is java.io.Serializable. A boolean flag which represents whether a value is present or not comes first. If a value is present, the value comes after the flag otherwise null comes after the flag.

MayBeValue is intended to represent optional fields in JSON schemas or JavaScript/TypeScript object literals. So, MayBeValue can be used as a field or parameter, whereas java.util.Optional can't.

JSON Schema to Java POJO

Here is a JSON schema that has an optional field baz. The value of field baz can be true, false or null.

{
    "foo": 123,
    "bar": "bar",
    "baz": true
}

{
    "foo": 123,
    "bar": "bar",
    "baz": null
}

{
    "foo": 123,
    "bar": "bar",
}

The JSON schema can represented like this:

public class Foo
{
    private Integer foo;

    private String bar;

    private MayBeValue<Boolean> baz;
}

Supported JDK versions

JDK 8 or newer.

Documentation

Clone this repository, move to the project directory and execute following command in your terminal:

gradle javadoc

The javadoc will be generated in build/docs/javadoc directory.

License

MIT