How to parse a string containing RDF n-triples?

How to parse a string containing RDF n-triples?

I have a file which reads rdf n-triples format. But, I am not allowed to
use third party API's (like jena etc... It's a different debate).
But basically, I can get two kinds of string:
<foo 1> <bar 1> <foo bar> .
<foo 2> <bar 2> foobar .
So, I want to write a class:
void ParseTriples(String s){
setObject(<foo> part)
setPredicate(<bar part>)
setObject(<foobar> or foobar)
}
How do I resolve this?