In many ways, Tarrant County District Attorney Joe Shannon Jr. is a continuation of his father’s legacy.Joe Shannon Sr., who was a lawyer, prosecutor, state legislator and district judge, was a committed public servant, who was more than pleased when his son decided to follow in his footsteps and get a law degree.The younger Shannon, 72, has practiced law in Tarrant County for more than 51 years, including more than 20 years in the District Attorney’s Office during two different stints. Like his dad, he also served in the Texas Legislature.After the death of long-serving District Attorney Tim Curry, Shannon was appointed by Gov. Rick Perry in 2009 to succeed his friend. Many considered him the logical choice for the job based on his experience. He ran for the position a year later and, with no Democrat in the race, he effectively won the election in the Republican primary, beating his opponent by 11 percentage points.Shannon announced to his staff Tuesday that he would not seek re-election next year and would retire from public office at the end of his term. His leaving will draw a close to that long legacy of public service.Some would suggest his decision to retire is motivated by a sexual harassment complaint against him by a former assistant district attorney that the commissioners court voted to settle last year for $375,000. Shannon vigorously denied the allegation, insisted he wanted the county to fight it but said he understands the commissioners “made a business decision” by settling the case.He still has more than a year in office, and he’s expected to continue running it in the tradition of his respected predecessor, and in his own fiscally and judicially responsible way.Meanwhile, he can sit on the sidelines and watch as a horde of candidates vie in what probably will be a lively campaign to replace him. It will be the first election for DA in Tarrant County in more than 40 years that does not include an incumbent in the race.That means Tarrant County voters will have to do their homework in selecting a new district attorney next year.