Re: java.net.URI implementation

[Per Bothner]

Giannis Georgalis wrote:
> The generated scanner is not big (about 300 loc).

A more interesting measure is .class file size.

> As you note, generated scanners are faster because they save a lot of
> function calls, have lookup tables,

Lookup tables are difficult when using Unicode - a simple
one-element-per-character table is too wasteful, at least
for a non-critical helper class like URI.

> and as far as I remember they
> work like FSMs (finite state machines).

That does not say anything about the implementation.
A hand-written scanner is also a FSM.

> Additionally don't forget
> that the URI objects are immutable. That means that as soon as the
> parsing is complete, the parser object is *dead*.

But you still have to allocate the parser object(s), which a
hand-written parser doesn't have to.  And object allocation
is relatively expensive, in the context of parsing a URI.
--
        --Per Bothner
address@hidden   http://www.bothner.com/per/