Where to put complex algorithms in Spring REST app

I am building out a Spring REST app that takes an inputted address, tries to parse it and match it against verified addresses in a database. the structure is:

app
 -controller
 -model
 -service
 -dao

The piece that 'parses' out the address is a package--let's call it AddressParser. It has some complex regular expressions, algorithms, etc..

My question is where should I put this package exactly as per best practice? I could place it as a separate package under 'app' or within the model?