public void addPhonenumber(String aPhonenumber){
  if (mPhoneNumbers.indexOf(aPhonenumber) < 0) {
    mPhoneNumbers.add(aPhonenumber);
  }
}

public void addPhonenumber ( String aPhonenumber ) { if ( mPhoneNumbers . indexOf ( aPhonenumber ) < 0 ) { mPhoneNumbers . add ( aPhonenumber ) ; } }
add a phone number address to the list .
