Question

I am creating a program to handle a text file different in different methods.
Like opening a filestream in one method, checking if it exists in another method, reading/writeing to the file in a third method and close the filestream in a fourth method.

This does not seem to go very well when I am using the same filestream in a method for checking if the file exists.

Main Code

//Imports the java.io library so the filehandler can read and write to text files.
import java.io.*;

public class filehandler    {

//Variables for the filehandler class.
public String filetohandlename;
public String filetohandleextention;
public String filetohandlefullname = filetohandlename + "." + filetohandleextention;
public String filetohandlepath;
public String filetohandle = filetohandlepath + filetohandlefullname;

//Boolean that is true if the filehandler's "openfilestream"-method has tried to open a filestream.
//Is false as long as none filestreams have been touched.
public boolean filestreamopen = false;

//Declares a variable for the filestream to access text files.
public File filestream;
//End of variable list.

//Called to open a filestream so the server can load properties from text files.
public void openfilestream(File filestream, String filetohandle)    {
    //Open a filestream called "filestream" using the variable "filetohandle"'s value
    //as information about wich file to open the filestream for.
    filestream = new File(filetohandle);
    //Turn the boolean "filestreamopen" to true so next time the server checks it's
    //value, it knows if the filehandler has tried to open a filestream.
    filestreamopen = true;
}

//Boolean that checks if the filestream exists.
public boolean filestreamexists(String filestream)  {
    //Tell the user that a check on the filestream is going on.
    System.out.println("Checking if filestream for \"" + filetohandlefullname + "\" exists...");
    //If the filestream exists...
    if(filestream.exists()) {
        //Tell the user that the filestream exists.
        System.out.println("Filestream for \"" + filetohandlefullname + "\" exists!");
        //Make the boolean's value positive.
        return true;
    }
    //If the filestream does not exist...
    else    {
        //Tell the user that the filestream does not exist.
        System.out.println("Filestream for \"" + filetohandlefullname + "\" does not exist!");
        //Make the boolean's value negative.
        return false;
    }
}

//Called to read files and collect it's information.
public void readfile(String filetohandle)   {
    //Checks if the file that is going to be read is a configuration file.
    if(filetohandleextention == "ini")  {
        //Tell the user that a configuration file is going to be read.
        System.out.println("Extracting information from the configuration file \"" + filetohandle + "\".");
    }
}
}

Problem

The problem lies in checking if the file exists. * if(filestream.exists()) { *
Within the method ” public boolean filestreamexists(String filestream) { “.

The code is simply stored in .java-files in a folder I call “source” and I am using a batch script to compile and run the code: javac -d binary source\*.java.

The error I get when I compile looks like this:

source\filehandler.java:36: error: cannot find symbol
                if(filestream.exists()) {
                             ^
  symbol:   method exists()
  location: variable filestream of type String

NOTE: “filehandler.java” is not the only source code playing a part in my program.
I also have a class called “server”, but it would probably be too long and boring to read if I were to include it in this post, but I got a very important part from the class I feel forced to include:

The server.java file is requesting both the methods “openfilestream” and “filestreamexists”.
This is the code I use when calling “filestreamexists”:

filehandlerclass.filestreamexists(filehandlerclass.filestream);

This gives me another error:

source\server.java:24: error: method filestreamexists in class filehandler canno
t be applied to given types;
                        filehandlerclass.filestreamexists(filehandlerclass.files
tream);
                                        ^
  required: String
  found: File
  reason: actual argument File cannot be converted to String by methodinvocatio
n conversation

Answer 1

Your problem is when you declare filestreamexists(). You declare it like this:

filestreamexists(String filestream) {

You are passing a string to it not a stream try something like this:

filestreamexists(File file){

And then you need to change the if to:

if(file.exists()) {

Also you have some errors in your fileopen, I think this should work better:

public File file;
public fileOpen(String fileToOpen) {
    filexists = true;
    try {
        filestream = New File(fileToOpen);
        //File exists
    } catch (IOException e) {
        filexists = false;
        // file doesn't exist
    }
}