Null and type safe meta data for Java

type-and-null-safe-meta-data.txt

given:

public class Foo {
	private String name;
	private Bar bar;
	
	public Foo(String name)
	{
		this.name = name;
		this.bar = new Bar(name+":bar");
	}
	public String getName()
	{
		return name;
		
	}
	public Bar getBar()
	{
		return bar;
	}
	
	public void setBar(Bar bar)
	{
		this.bar = bar;
	}
}

and:

public final class FooMeta
	extends Meta<Foo, FooMeta.Property>
{
	public enum Property
	{
		bar,
		name
	};	
	
	public static FooMeta META = new FooMeta();
	
	public static final Getter<Bar> getBar = META.new Getter<Bar>(Property.bar);
	public static final Setter<Bar> setBar = META.new Setter<Bar>(Property.bar);
	public static final Getter<String> getName = META.new Getter<String>(Property.name);

}

then:

    final Foo foo = ...;
    final Unary<Foo, String> path =  FooMeta.getBar.deref(BarMeta.getName);

such that:

    path.apply(foo)

produces almost same output as:

     foo.getBar().getName();

It is a little better, however, because if foo.getBar() is null, then path.apply(foo) yields null whereas
foo.getBar().getName() yields a NullPointerException.

The cool thing is that FooMeta can be generated with a reasonably trivial code generation step.