CODEWITHSUNDEEP
javafile
Shan
Shan

Reputation: 475

List all folders in a directory without changing order even when new files are added

How to list all folders in a directory without changing order even when new files are added, in a file using Java? When I run the program it is going to an infinite loop with "Not checked" comment which I put in order to look whether it is checking the file. 

    try
    {
        BufferedWriter bufferedWriter = null;
        bufferedWriter = new BufferedWriter(new FileWriter("d://my.txt"));
        BufferedReader br = new BufferedReader(new FileReader("d://my.txt"));

        int i=1;
        File f=new File("D:/Moviezzz");
        File[] fi=f.listFiles();
        for(File fil:fi)
        {
            if(!fil.isHidden() && (fil.isDirectory() || fil.isFile()))
            {
                int s=i++;

                String files = fil.getName();

                String thisLine;
                while(null != (thisLine="\t"+br.readLine()))
                {
                    String exist[]=thisLine.split("\t");
                    //ensure that it is already written in file 
                    if(exist[0].equals(files))
                    {
                        System.out.println("Checked");
                    }
                    //ensure that it is not written in file 
                    else
                    {
                        System.out.println("Not Checked");
                    }
                }
                bufferedWriter.write(s+"\t"+files);
                bufferedWriter.newLine();
                bufferedWriter.flush();
                System.out.print("yes");

                // bufferedWriter.write(s+" "+files);
            }    
            br.close();
            //Construct the BufferedWriter object
            System.out.println("Succ");
        }
    }
    catch(Exception ex)
    {
        System.out.println("failed");  
    }

Upvotes: 1

Views: 187

Answers (1)

Sam I am says Reinstate Monica
Sam I am says Reinstate Monica

Reputation: 31194

You're getting an infinite loop, because the condition in your while loop can never be false.

while(null != (thisLine="\t"+br.readLine()))

you're essentially adding "\t" to the results of readLine(), so the value you're comparing to null will never actually be null. It will always have a \t in it.

After further research, it appears like thisLine will be be "\tnull" once you've reached the end of the stream

If I were you, I wouldn't do all that in your while loop. I'd do something more like this.

while(null != (thisLine=br.readLine()))
{
    thisLine = "\t"+ + thisLine;
    ...

Upvotes: 2

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