Trying to concatenate a series of strings via array

Question

having a little bit of an issue. I am looping through a file where by I want to filter out a series of texts and concatenate them at the end of each loop, which then ultimately end up ordering i.e. during the loop phase it does the following:

String A = "A /n"
String A = "A /n U /n"
String A = "A /n U /n  B /n"

etc...

The output will be

A

U

B

however i want it to be

A

B

U

I have so far done the following:

public static void organiseFile() throws FileNotFoundException {
    ArrayList<String> lines = new ArrayList<>();
    ArrayList<String> order = new ArrayList<>();
    String directory = "C:\\Users\\xxx\\Desktop\\Files\\ex1";
    Scanner fileIn = new Scanner(new File(directory + "_ordered.txt"));
    PrintWriter out = new PrintWriter(directory + "_orderesqsd.txt");
    String otherStates = "";

    while (fileIn.hasNextLine() == true) {
        lines.add(fileIn.nextLine());
        System.out.println("Organising...");
    }
    Collections.sort(lines);
    for (String output : lines) {
        if (output.contains("[EVENT=agentStateEvent]")) {
            out.println(output + "\n");
            out.println(otherStates + "\n");
            otherStates = "";
        }
        else {
        otherStates += output+ "\n";    
    }
    out.close();
}

Now this does output fine, however, with regards to the "otherStates", i want to get this in a numeric order, and the best way I know is using Collections, however this is for arrays. I am unsure how to go about modifying the "otherStates" part of the code to cater for an array that concatanetates the string and then be able to order them accordingly. Any ideas

Your question is very unclear - "i want to get this in a certain order" doesn't explain what ordering you want at all. Why are you collecting otherStates as a single string, rather than as a collection of some kind? If you want to reorder things, gather all the elements as a collection, order them, and then join them together... — Jon Skeet
– Jon Skeet, Commented Oct 6, 2015 at 8:48
This is where i am struggling. I know the otherStates needs to be changed from a string to an Array so I can order it using collections.sort. I have an array called "order" however i cannot simply replace "otherStates" with "order". — Raziel
– Raziel, Commented Oct 6, 2015 at 8:55
You don't have any arrays. You have ArrayLists. They're not the same thing. But you can create a third ArrayList for otherStates and add to that instead of using string concatenation - what's stopping you from doing that? — Jon Skeet
– Jon Skeet, Commented Oct 6, 2015 at 8:56

Raj · Accepted Answer · 2015-10-06 09:27:06Z

Hard to give a correct solution without input file data . Just try the below code. At the very least it should give you some ideas on how to solve the issue

public static void organiseFile() throws FileNotFoundException {
ArrayList<String> lines = new ArrayList<>();
ArrayList<String> order = new ArrayList<>();
String directory = "C:\\Users\\xxx\\Desktop\\Files\\ex1";
Scanner fileIn = new Scanner(new File(directory + "_ordered.txt"));
PrintWriter out = new PrintWriter(directory + "_orderesqsd.txt");

String otherStates = "";
ArrayList<String> otherStates_duplicate = new ArrayList<>();
String ordered_new_string.;

while (fileIn.hasNextLine() == true) {
    lines.add(fileIn.nextLine());
    System.out.println("Organising...");
}
Collections.sort(lines);
for (String output : lines) {
    if (output.contains("[EVENT=agentStateEvent]")) {
        out.println(output + "\n");
        out.println(otherStates + "\n");
        otherStates = "";
    }
    else {
    otherStates += output+ "\n"; 
    otherStates_duplicate.add(output);

}
Collections.sort(otherStates_duplicate); // Now this should have a sorted list

//if you need a string instead of an arraylist use code below in addition
for(String s:otherStates_duplicate){ 

ordered_new_string += s + "\n";

}

/*
I have not printed or stored the string ordered_new_string as it is not
 clear to me what you want. print/write to a file and check 
if ordered_new_string is what your required

*/

out.close();
}

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