Generate tree path of a string

Question

I have a tree that looks like the following (a simple example, can be a variable size).

1 (root)
|---------------------------------|
1-1                              1-2
|------------|                    |--------------|
1-1-1     1-1-2                  1-2-1          1-2-2

I've written a Java class to generate this tree based on NumberOfSiblings (horizontal) and NumberOfChildren (vertical). I'm now looking to write a class that will generate the path of a given entry in the tree, for example:

Entry: 1-1-1
Path: /1/1-1/1-1-1

I believe that I need some sort of recursive method that will count the number of dashes and take off the last part of the entry (not always length() - 2 though as it could be 10-10-10).

This is the method that will generate the tree:

public static void generateCatalog(String parent, int siblings, int children, int level) {
    for (int a = 1; a <= siblings; a++) {
        String child = parent + "-" + a;
        System.out.println(child);
        if (level <= children) {
            level++;
            generateCatalog(child, siblings, children, level);
            level--;
        }
    }
}

I've been trying something like this to generate the path but it does not work very well.

public static void getPath(String category, String path) {
    System.out.println("Category: " + category);
    System.out.println("Current path: " + path);
    int numberOfDashes = category.length() - category.replace("-", "").length();
    System.out.println("Number of dashes: " + numberOfDashes);
    while (numberOfDashes > 1) {
        path = category + "/" + category.substring(0, category.length() - 2);
        getPath(category, path);
    }
    System.out.println("New path: " + path);
}

Could someone please tell me the best way to do this?

No need to add the tags to the questions. I removed it for you ;-) — Burkhard
– Burkhard, Commented Jul 2, 2013 at 13:42

Pat Lillis · Accepted Answer · 2013-07-02 13:48:51Z

1

Instead of

path = category + "/" + category.substring(0, category.length() - 2);

Try

int endIndex = category.lastIndexOf("-");
if(endIndex != -1)  {
     path = category + "/" + category.subString(0, endIndex);
}

Not sure what you want to do if there aren't any dashes, but just stick that in an else block.

answered Jul 2, 2013 at 13:48

Pat Lillis

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