File Filter in JTree

[Fadly Massere]

Hello,
This is my code,
My goal is to display file that have extension *.java,
What I am suppose to do ?
I was wrote this swing in netbeans,

private static class FileSystemModel implements TreeModel {
    
        private File root;

        private Vector listeners = new Vector();

        public FileSystemModel(File rootDirectory) {
            root = rootDirectory;
        }

        @Override
        public Object getRoot() {
            return root;
        }
        
        class filterJava implements FilenameFilter {

            @Override
            public boolean accept(File dir, String name) {
                String lowerCaseName = name.toLowerCase();
                return lowerCaseName.endsWith(".java");
            }

        }
        
        @Override
        public Object getChild(Object parent, int index) {
            File directory = (File) parent;
            String[] children = directory.list(new filterJava());
            for(int a=0; a < children.length; a++){
                System.out.println(children[a]);
            }
            return new TreeFile(directory, children[index]);
        }

        @Override
        public int getChildCount(Object parent) {
            File file = (File) parent;
            if (file.isDirectory()) {
                String[] fileList = file.list(new filterJava());
                if (fileList != null) {
                    return file.list().length;
                }
            }
            return 0;
        }

I got this message

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 0

what I am supposed to do ?

[Norm]

What line in the source did that error happen on?

[Fadly Massere]

there is no error in compile,
when I am execute, the out message just "Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 0"

The original code is

public Object getChild(Object parent, int index) {
            File directory = (File) parent;
            String[] children = directory.list(new filterJava());
            for(int a=0; a < children.length; a++){
                System.out.println(children[a]);
            }
            return new TreeFile(directory, children[index]);
        }
 
        @Override
        public int getChildCount(Object parent) {
            File file = (File) parent;
            if (file.isDirectory()) {
                String[] fileList = file.list(new filterJava());
                if (fileList != null) {
                    return file.list().length;
                }
            }
            return 0;
        }

I think the problem is the filter in the getChild and getChildCount
"String[] children = directory.list(new filterJava());"
am I ?

[Norm]

The execution time error should show the source line number where the error happened.
For example:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at TestCode17.main(TestCode17.java:241)

shows error happened at line 241

[Fadly Massere]

this error :
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 0
at Tampilan.Main_Menu$FileSystemModel.getChild(Main_M enu.java:222)

which is

return new TreeFile(directory, children[index]);

now what ?

[Norm]

The error message says that the array at line 222 has no element at index 0 which means the array is empty.
The code needs to test for that the index into the array does not go past the last element in the array.
Use an if to test that the array has enough elements and
either don't call the constructor
or pass another value to the constructor
or ???

[Fadly Massere]

The error message says that the array at line 222 has no element at index 0 which means the array is empty.
The code needs to test for that the index into the array does not go past the last element in the array.
Use an if to test that the array has enough elements and
either don't call the constructor
or pass another value to the constructor
or ???

can u give ne an example ?

[Norm]

I don't know what the getChild() method is supposed to return.
One option might be a null if there are no children:

if(children.length == 0)   // test if there are any children
  return null;    // return null if there are none