// imports
// java.util.Scanner to read from command line
import java.util.Scanner;

// compile with javac
// or in vsc with java export jar
// run with java -jar appWrapperClass.jar

// class to hold main
class appWrapperClass {
    public static void main(String[] args) {

        // Print to Command Line
        System.out.println("Hello World");

        // Create Scanner to Read from command line
        Scanner nS = new Scanner(System.in);
        // Read from command line
        String readFromConsol = nS.nextLine();
        // Create string
        String reply = "reply: ";
        // Print Concatenated Vars
        System.out.println(reply + readFromConsol);
        nS.close(); // only use if console input not required again!

        // Create String Array
        String[] sA = new String[2];

        // Add Values to Array
        sA[0] = "A";
        sA[1] = "B";

        // Loop and print Array Values
        for (int i = 0; i < sA.length; i++) {
            System.out.println(sA[i]);
        }

        // Basic if statement
        if (sA[1] == "B") {
            System.out.println("Yep its B");
        } else {
            System.out.println("Nope not B");
        }

        // Create integer variable
        int x = 10;

        // Basic while loop
        while (x > 0) {
            System.out.println(x);
            x -= 1;
        }

        // try catch - demo divide by zero error
        try {
            int z = 1 / 0;
        } catch (Exception e) {
            // TODO: handle exception
            System.out.println("Oh Dear: " + e);
        }

        // Call static function in same class 
        newFunc();
        // Call  static function in extended from this class (external file in same directory)
        names.wotcher();

        // Call static function in non extended  class with var (external file in same directory)
        other.stuff("some");

        // Call static function in non extended  class  (external file in same directory)
        fileHandling.makeFile();
        fileHandling.readFile();

    }

    // 2nd static function in this class 
    static void newFunc() {
        // Print to Command Line
        System.out.println("From newFunc.");
    }
}

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.PrintWriter;


public class fileHandling {

    public static void makeFile() {

        // Make New File
        File x = new File("FromJava.txt");
        try {
            FileWriter fw = new FileWriter(x.getName());
            // Write To New File
            fw.append("Hello");
            // Close Writer
            fw.close();

            // open Writer For Existing File
            fw = new FileWriter("toapp.txt", true);
            // make BufferedWriter for multi append efficiency
            BufferedWriter bw = new BufferedWriter(fw);
            // make PrintWriter to Write from BufferedWriter for multi append efficiency
            PrintWriter pw = new PrintWriter(bw);
            // Append Line
            pw.println("Hello App\n");
            // Close PrintWriter
            pw.close();
            // Close BufferWriter
            bw.close();
            // Close FileWriter
            fw.close();

        } catch (Exception e) {
            // handle exception
            System.out.println("OOPS - Error In makefile function");
            // quit app
            System.exit(0);
        }
    }

    public static void readFile() {

        try {
            // make FileReader
            FileReader fr = new FileReader("toapp.txt");
            // get 1 st char as int
            int z = fr.read();
            // if int = -1  then EOF
            // Loop all read values
            while (z > 0) {
                // print int returned as its character
                System.out.print(Character.toChars(z));
                // read next character
                z = fr.read();
            }
            // Close the FileReader
            fr.close();
            
        } catch (Exception e) {
            // handle exception
            System.out.println("OOPS - Error Reading File");
            // quit app
            System.exit(0);
        }
    }

}

public class names extends appWrapperClass {
    static void  wotcher() {
        // Print Line 
        System.out.println("wotcher");
    }    
}

public class other {

    // function requiring a string parameter
    public static void stuff(String prefix) {
        // Print Line of variable concatanated with string
        System.out.println(prefix + " other stuff");
        // Run a Function 
        sqeel();
    }

    // SQL Read And Print
    // Need to add Referenced Library mssql-jdbc-12.6.1.jre8.jar (based on runtime etc)
    // Add directly in VSC with VSC recommended java extensions
    // Available as zip download from MS
    // - see also .vscode/settings.json
    public static void sqeel() {
        // Try Catch
        try {
            // Make a Connection Object
            Connection conn = DriverManager.getConnection(
                    "jdbc:sqlserver://<SERVER_NAME>;Database=<DATABASE_NAME>;user=<USER>;password=<PASSWORD>;trustServerCertificate=true");
            // Print Connection Confirmation
            System.out.println("Yay sqeel connected!");
            // Make SQL statement Object
            Statement stmt = conn.createStatement();
            // Make SQL ResultSet Object and populate with data from SQL Query (stmt.executeQuery(<SQL>))
            ResultSet rs = stmt
                    .executeQuery("SELECT TOP 10 [<FIELD1>],[<FIELD2>] FROM <TABLE_OR_VIEW>");
            // Loop using .next() on ResultSet
            while (rs.next()) {
                System.out.println(
                    // Print Field Values with rs.getString(<SQL_FIELD_NAME>)
                    rs.getString("<FIELD1>") + ":" +
                    rs.getString("<FIELD2>"));
            }
            // Close ResultSet
            rs.close();
            // Close Statement
            stmt.close();
            // Close Connection
            conn.close();

        } catch (Exception e) {
            // handle exception: write "Boo:" + error details
            System.out.println("Boo: " + e);
            // Exit App
            System.exit(0);
        }

    }
}