Firstly, it's definitely not written in eye dialect (it's basically a dialect or language of Joyce's own invention)
Beyond that, even if you were to consider accents of Joyce & his contemporaries, along with the changes of accents over 100 years, Joyce—from a Catholic, but well-off background—had an accent[0] much closer to a modern English accent than anything else.
He also lived in Italy, Switzerland and France for most of his life.
Hmm. I have to say that Joyce doesn't sound like any English person I've ever met!
His accent is fairly typical of the educated middle class Dubliner of the era and can be heard in recordings of some Irish politicians from the period. Ireland was a dominion of the British empire during Joyce's formative years, and the influence of English RP is obvious. However, his Hibernian roots are also clearly audible, at least to me!
Firstly, it's definitely not written in eye dialect (it's basically a dialect or language of Joyce's own invention)
Beyond that, even if you were to consider accents of Joyce & his contemporaries, along with the changes of accents over 100 years, Joyce—from a Catholic, but well-off background—had an accent[0] much closer to a modern English accent than anything else.
He also lived in Italy, Switzerland and France for most of his life.
[0] https://www.youtube.com/watch?v=ZhW0TrzWGmI