cross platform clinic schedule system with java

I need to build a clinic schedule system with java and it's should work in all platforms Main requirement: Allows for scheduling of one to many clinics schedule to be managed centrally (Optional) Fully graphical with easy 1 to 2 steps for each function ( eg Enter new appointment, change appointment etc) Ability to record down basic patient information such as patient name to very detailed information such as patient's address, contacts and brief notes on appointment Ability to view clinic, patient and doctor appointment schedule in different formats - daily, calendar or diary-like list Ability to view in different schedule time intervals - 1,2,3,4,5,6,10,20,30 and 60 mins Ability to associate with different attending Doctors. Colour-coded to differentiate different doctor Ability to select category (eg Xray, Health Screening, Lasik) Categories are denoted in different colours Enable Clinic Managers or Doctor to block out time slots so that the appointed user does not accidentally setup appointment on those block-out time slots (also known as BlackOut slots) Ability to 'double-book', 'triple-book' or more where user can accomodate more than one patient on the same or portion of the same time slot Setup early patient appointment reminder and alert (Optional) User is warned if he/she tries to book the same time slot for resources that have a constraint. For example, certain laser equipments cannot be allowed to be booked twice in same time slot User is warned if patient has made an appointment earlier on thus preventing duplication of records User can view followup appointments of a patient in a single glance ability to add two way integration (sync) the calendar with online calendar system more technical requirement will discussed later