Java Save/Load Optimization

Question

I have recently gotten into Java in a Computer Science class at my high school and I am trying to learn more than just the basics I have learned in school. Yesterday, I designed a very simple text editor I named Aqua that is written with Swing. For some reason, my computer drags a little bit when I run these methods. Is it because I have a crappy computer or did I write something wrong? Thanks!

private void save(String content, String name) throws IOException{
    System.out.println(dir.toString());
    if(firstRun<1){
        dirCreation();
        firstRun++;
    }
    try{
            String savedText = content;
            System.out.println(savedText);
            File newTextFile = new File(newDir.toString() + File + name + ".aqua");
            System.out.println(newDir.toString() + File.seperator + name + ".aqua");
            if (!newTextFile.exists()) {
                System.out.println("Created new File");
                newTextFile.createNewFile();
            }
        try (FileWriter fw = new FileWriter(newTextFile)) {
            fw.write(savedText);
        }

    }
    catch(IOException x){
                System.err.format("IOException: %s%n", x);
    }
}
private void load(String name) throws FileNotFoundException, IOException{
    if(firstRun<1){
        dirCreation();
        i++;
    }

    File loadingFile = new File(newDir + "\\" + name + ".aqua");
    Scanner scan = new Scanner(loadingFile);
    StringBuilder loadedText = new StringBuilder("");
    while (scan.hasNextLine()) {
            loadedText.append(scan.nextLine() + "\n");
            //Is this correct usage of StringBuilder?
    }
    jTextArea1.setText(out);        
    }

Answer 1

There are formatting and whitespace issues in your code, fix them! You're also switching between declaring variables and initializing them in the next line and initializing them in the same line, be consistent!

---

if(i<1){

That hurts! What is i? Where does it come from? Why do you check against less then one? Keep your variable names always clear, f.e. numberOfLinesInFile is way better then i in my opinion.

---

new File(newDir.toString() + "\\" + name + ".aqua");

This assumes that it is run on a Windows machine (or anything else that uses a backslash as path separator...which I hope no one else does). That will lead lead to problems on *nix machines, but I know that / works on any platform, you could also go full length and use File.separator.

Or you use the constructor-overload that is provided for exactly these means:

new File(newDir.toString(), name + ".aqua"):

---

String out = "";

That's not a great name for that variable, text or content would be better suited.

---

out+=line + "\n";

This has one problem, concatenating strings with the + is slow like whatever-place-of-ternal-pain-you-believe-in-if-any. Use a StringBuilder, that will speed things up considerable.

---

jTextArea1.setText(out);

Again, not a good name.

Answer 2

First and most important: you are using Java 1.7 (as the try-with-resource statement proves), so do yourself a favor: use Files! The File API should have been marked as deprecated ever since this new API was here.

In most situations, the Files class itself is all you need:

Path dir = Paths.get("/path/to/directory");
Path file = dir.resolve("nameOfFile");
// Create a directory, including parents
Files.createDirectories(dir);
// Write the contents of a string to a file
Files.copy(new ByteArrayInputStream(text.getBytes("UTF-8")), file);

Drop File. Real fast. Among the many, many problems it has, look at this line in your code:

// DOES NOT THROW AN EXCEPTION IF IT FAILS!
newTextFile.createNewFile();