Implementation of a Hospital management system using ArrayList in Java

 package arraylist.hospital; import java.text.SimpleDateFormat; import java.util.*; import java.io.*; public class HospitalProcess { static ArrayList<Patient> arl = new ArrayList<Patient>(); static String joindate; public static void main(String[] args) throws IOException { char l='i'; Calendar currentDate = Calendar.getInstance(); SimpleDateFormat formatter= new SimpleDateFormat("yyyy/MMM/dd HH:mm:ss"); joindate = formatter.format(currentDate.getTime()); Patient p1 = new Patient(1,"Raja", "Miyapur,Hyderabad", 40, 'm', "Fever", 250f, joindate); arl.add(p1); Patient p2 = new Patient(2,"Rani", "Madhapur,Hyderabad", 45, 'f', "Cough", 250f, joindate); arl.add(p2); Patient p3 = new Patient(3,"James", "Hydernagar,Hyderabad", 56, 'm', "Cancer", 250f, joindate); arl.add(p3); do { Patient p = new Patient(); System.out.println("Enter 1 to register a Patient \n 2 to update Patient details \n 3 to deactivate Patient details \n 4 to display Patient details"); BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); int choice = Integer.parseInt(br.readLine()); switch(choice) { case 1: p.registerPatient(); System.out.println("Patient Registered Successfully !!!"); p.showPatientDetails(); break; case 2: p.showPatientDetails(); p.updatePatientDetails(); break; case 3: p.removeInactivePatient(); break; case 4: Collections.sort(arl); p.showPatientDetails(); break; default: System.out.println("Patient does not exist with the entered ID"); System.out.println("Try again"); break; } System.out.println("Do you want to continue selecting options (y/n):"); l=(char)br.read(); }while(l=='y'); } // End of main() method } // ************* End of HospitalProcess class ****************** // *********** Patient class to implement operations ******************* class Patient implements Comparable<Patient> { int patientID; String patientName; String patientAddress; int age; char patientSex; String patientIllness; float amountForAppointment; String joindate; HospitalProcess hm = new HospitalProcess(); Patient() {} public int compareTo(Patient p) { return this.patientID = p.patientID; } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); Patient(int patientID,String patientName,String patientAddress,int age,char patientSex,String patientIllness,float amountForAppointment, String joindate) { this.patientID=patientID; this.patientName=patientName; this.patientAddress=patientAddress; this.age=age; this.patientSex=patientSex; this.patientIllness=patientIllness; this.amountForAppointment=amountForAppointment; this.joindate = joindate; } void registerPatient()throws IOException //function to insert new patient records { Patient pr = new Patient(); @SuppressWarnings("static-access") int patientID= hm.arl.size(); pr.patientID = patientID+1; System.out.println("Enter Patient name:"); pr.patientName = br.readLine(); System.out.println("Enter Patient Address:"); pr.patientAddress = br.readLine(); System.out.println("Enter Patient Age:"); pr.age = Integer.parseInt(br.readLine()); System.out.println("Enter Patient Sex:"); String temp = br.readLine(); pr.patientSex =temp.charAt(0); System.out.println("Enter Patient Illness:"); pr.patientIllness = br.readLine(); System.out.println("Enter the amount patient needs to pay for appointment:"); pr.amountForAppointment = Float.parseFloat(br.readLine()); pr.joindate = hm.joindate; hm.arl.add(pr); } @SuppressWarnings("static-access") void removeInactivePatient() throws IOException //function to remove patient records { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); System.out.println("Enter Patient ID:"); int id1 = Integer.parseInt(br.readLine()); int flag=0; int flag2=0; String presentdate; String afteraddingdays; for(int i=0; i<hm.arl.size(); i++) { if(id1 != hm.arl.get(i).patientID) { flag=0; } else if(id1 == hm.arl.get(i).patientID) { presentdate = hm.arl.get(i).joindate; Calendar cal = Calendar.getInstance(); cal.add(Calendar.DAY_OF_MONTH, 15); SimpleDateFormat formatter = new SimpleDateFormat("yyyy/MMM/dd HH:mm:ss"); afteraddingdays = formatter.format(cal.getTime()); flag=1; if(presentdate == afteraddingdays) { hm.arl.remove(i); System.out.println("Patient deleted as his validity expired"); flag2=1; } else{ flag2=0; } } } if((flag) == 0) { System.out.println("Patient with the entered ID does not exist"); } if(flag2==0) { System.out.println("Patient has still days left before his appointment expires"); } } // Function to update patient records void updatePatientDetails() throws IOException { char l='n'; Patient p2 = new Patient(patientID, patientName, patientAddress, age, patientSex, patientIllness, amountForAppointment, joindate); do{ System.out.println("Enter patient ID you want to update:"); BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); int idnum = Integer.parseInt(br.readLine()); for(int i=0; i<hm.arl.size(); i++) { if(idnum == hm.arl.get(i).patientID) { System.out.println("Enter 1 to change patient's name \n 2 to change patient's address \n 3 to change patient's age \n 4 to change patient's illness \n 5 to change registration fees along with the medical expenses"); int ch = Integer.parseInt(br.readLine()); switch(ch) { case 1: System.out.println("Enter new patient's name:"); p2.patientName = br.readLine(); p2.patientID= hm.arl.get(i).patientID; p2.patientAddress= hm.arl.get(i).patientAddress; p2.age=hm.arl.get(i).age; p2.patientSex=hm.arl.get(i).patientSex; p2.patientIllness = hm.arl.get(i).patientIllness; p2.amountForAppointment = hm.arl.get(i).amountForAppointment; p2.joindate = hm.arl.get(i).joindate; hm.arl.set(i,p2); System.out.println("Patient updated !!!"); break; case 2: System.out.println("Enter new patient Address:"); p2.patientAddress = br.readLine(); p2.patientID = hm.arl.get(i).patientID; p2.patientName = hm.arl.get(i).patientName; p2.age = hm.arl.get(i).age; p2.patientSex = hm.arl.get(i).patientSex; p2.patientIllness = hm.arl.get(i).patientIllness; p2.amountForAppointment = hm.arl.get(i).amountForAppointment; p2.joindate = hm.arl.get(i).joindate; hm.arl.set(i,p2); System.out.println("Patient updated !!!"); break; case 3: System.out.println("Enter new Patient age:"); p2.age = Integer.parseInt(br.readLine()); p2.patientID = hm.arl.get(i).patientID; p2.patientName = hm.arl.get(i).patientName; p2.patientAddress = hm.arl.get(i).patientAddress; p2.patientSex = hm.arl.get(i).patientSex; p2.patientIllness = hm.arl.get(i).patientIllness; p2.amountForAppointment = hm.arl.get(i).amountForAppointment; p2.joindate= hm.arl.get(i).joindate; hm.arl.set(i,p2); System.out.println("Patient updated !!!"); break; case 4: System.out.println("Enter new Patient illness:"); p2.age = hm.arl.get(i).age; p2.patientID= hm.arl.get(i).patientID; p2.patientName = hm.arl.get(i).patientName; p2.patientAddress = hm.arl.get(i).patientAddress; p2.patientSex = hm.arl.get(i).patientSex; p2.patientIllness = br.readLine(); p2.amountForAppointment = hm.arl.get(i).amountForAppointment; p2.joindate = hm.arl.get(i).joindate; hm.arl.set(i,p2); System.out.println("Patient updated !!!"); break; case 5: System.out.println("Enter the new amount that patient needs to pay:"); p2.age = hm.arl.get(i).age; p2.patientID = hm.arl.get(i).patientID; p2.patientName = hm.arl.get(i).patientName; p2.patientAddress = hm.arl.get(i).patientAddress; p2.patientSex = hm.arl.get(i).patientSex; p2.patientIllness = hm.arl.get(i).patientIllness; p2.amountForAppointment = Float.parseFloat(br.readLine()); p2.joindate = hm.arl.get(i).joindate; hm.arl.set(i,p2); System.out.println("Patient details updated !!!"); break; default: System.out.println("Invalid choice."); break; } // End of switch block }// End of if block } // End of for block System.out.println("Do you want to continue updating (y/n):"); l=(char)br.read(); }while(l=='y'); //*End of do-while block */ } //* Function to display patients details*/ void showPatientDetails() { System.out.println("patient-ID \t Patient-Name \t Address \t\t Age \t Sex \t Illness \t Fees \t Join-date"); for(int i=0; i<hm.arl.size(); i++) { System.out.println(hm.arl.get(i).patientID + " \t\t "+hm.arl.get(i).patientName+" \t\t "+hm.arl.get(i).patientAddress+" \t "+hm.arl.get(i).age+" \t "+hm.arl.get(i).patientSex+" \t "+hm.arl.get(i).patientIllness+" \t\t "+hm.arl.get(i).amountForAppointment+" \t "+hm.arl.get(i).joindate); } } } /********* End of Patient class **************/