Code 2

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.ArrayList;

public class Pass2 {
    ArrayList<TableRow> SYMTAB,LITTAB;

    public Pass2()
    {
        SYMTAB=new ArrayList<>();
        LITTAB=new ArrayList<>();
    }
    public static void main(String[] args) {
        Pass2 pass2=new Pass2();

        try {
            pass2.generateCode("IC.txt");
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    public void readtables()
    {
        BufferedReader br;
        String line;
        try
        {
            br=new BufferedReader(new FileReader("SYMTAB.txt"));
            while((line=br.readLine())!=null)
            {
                String parts[]=line.split("\\s+");
                SYMTAB.add(new TableRow(parts[1], Integer.parseInt(parts[2]),Integer.parseInt(parts[0]) ));
            }
            br.close();
            br=new BufferedReader(new FileReader("LITTAB.txt"));
            while((line=br.readLine())!=null)
            {
                String parts[]=line.split("\\s+");
                LITTAB.add(new TableRow(parts[1], Integer.parseInt(parts[2]),Integer.parseInt(parts[0])));
            }
            br.close();
        }
        catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }

    public void generateCode(String filename) throws Exception
    {
        readtables();
        BufferedReader br=new BufferedReader(new FileReader(filename));

        BufferedWriter bw=new BufferedWriter(new FileWriter("PASS2.txt"));
        String line,code;
        while((line=br.readLine())!=null)
        {
            String parts[]=line.split("\\s+");
            if(parts[0].contains("AD")||parts[0].contains("DL,02"))
            {
                bw.write("\n");
                continue;
            }
            else if(parts.length==2)
            {
                if(parts[0].contains("DL")) //DC INSTR
                {
                    parts[0]=parts[0].replaceAll("[^0-9]", "");
                    if(Integer.parseInt(parts[0])==1)
                    {
                        int constant=Integer.parseInt(parts[1].replaceAll("[^0-9]", ""));
                        code="00\t0\t"+String.format("%03d", constant)+"\n";
                        bw.write(code);


                    }
                }
                else if(parts[0].contains("IS"))
                {
                    int opcode=Integer.parseInt(parts[0].replaceAll("[^0-9]", ""));
                    if(opcode==10)
                    {
                        if(parts[1].contains("S"))
                        {
                            int symIndex=Integer.parseInt(parts[1].replaceAll("[^0-9]", ""));
                            code=String.format("%02d", opcode)+"\t0\t"+String.format("%03d", SYMTAB.get(symIndex-1).getAddress())+"\n";
                            bw.write(code);
                        }
                        else if(parts[1].contains("L"))
                        {
                            int symIndex=Integer.parseInt(parts[1].replaceAll("[^0-9]", ""));
                            code=String.format("%02d", opcode)+"\t0\t"+String.format("%03d", LITTAB.get(symIndex-1).getAddress())+"\n";
                            bw.write(code);
                        }

                    }
                }
            }
            else if(parts.length==1 && parts[0].contains("IS"))
            {
                int opcode=Integer.parseInt(parts[0].replaceAll("[^0-9]", ""));
                code=String.format("%02d", opcode)+"\t0\t"+String.format("%03d", 0)+"\n";
                bw.write(code);
            }
            else if(parts[0].contains("IS") && parts.length==3) //All OTHER IS INSTR
            {
            int opcode= Integer.parseInt(parts[0].replaceAll("[^0-9]", ""));

            int regcode=Integer.parseInt(parts[1]);

            if(parts[2].contains("S"))
            {
                int symIndex=Integer.parseInt(parts[2].replaceAll("[^0-9]", ""));
                code=String.format("%02d", opcode)+"\t"+regcode+"\t"+String.format("%03d", SYMTAB.get(symIndex-1).getAddress())+"\n";
                bw.write(code);
            }
            else if(parts[2].contains("L"))
            {
                int symIndex=Integer.parseInt(parts[2].replaceAll("[^0-9]", ""));
                code=String.format("%02d", opcode)+"\t"+regcode+"\t"+String.format("%03d", LITTAB.get(symIndex-1).getAddress())+"\n";
                bw.write(code);
            }
            }
        }
        bw.close();
        br.close();
    }
}