cw3b.java

a Java program that reads a file containing instructions written in self-defined file (TPL in this c

import java.io.*;
import java.util.*;


public class cw3b
{
	//declare class variable
	static String fname;
	static String line;
	
	
	//print out file into console when there is "end" statement
	//method take fname as parameter
	static void print(String fname)
	{
		//declare count variable for counting numbers of line printed
		int count=0;
			
		try{
				//use BufferedReader and FileReader read in file
				BufferedReader inFile=new BufferedReader(new FileReader(fname));
				String nline;	
				//use while loop to read in every line
				while(( nline=inFile.readLine())!=null&&(nline.equalsIgnoreCase("end"))!=true)	
				{
				
						System.out.println(nline);
						count++;
			
				}
			}catch(IOException e){
					System.out.println("an error ["+e+"]");
			}
		//print out final statement into console
		System.out.println("TPL Finished ok ["+(count+1)+" lines processed]");
	}
	
	//method exit for stop application when there is no end Statement
	private static void exit()
	{
		//print out "no end" error message
		System.out.println("No end statement");
		System.exit(0);							//exit application
	}
	
	//main method
	public static void main(String args[])
	{	
		//declare boolean x,y 
		//initialize x value as false
		boolean x=false;
		boolean y;
		//take commandline args as parameter
		if(args.length>=1)
		
		{	
			try{
					BufferedReader inFile=new BufferedReader(new FileReader(args[0]));
					//fname is command line args
					for(int i=0;i<args.length;i++)
						fname=args[i];
						//use while loop to search for "end" statement
						//if yes, x vulue changes to true
						while((line=inFile.readLine())!=null)	
					 	{
					 	
					 		y=line.equalsIgnoreCase("end");		//y values changes according to line content
					 		if( y==true)						//last line content decides y final values
					 		{
					 			x=y;							//x equals to y when y is true
					 			print(fname);					//invoke print method
					 		}
					 	}
					 	if(x==false)							//no end statement
					 		exit();						//invoke exit method
					 
				}catch(IOException e){
					System.out.println("an error ["+e+"]");
				}
		}
		else
			System.out.println("no such file");		//no command line args print out error message
	
		
	}
		
				
}