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diff --git a/Bachelor/ERGO/FileTreeDemo.java b/Bachelor/ERGO/FileTreeDemo.java
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+/*
+ * This example is from the book "Java Foundation Classes in a Nutshell".
+ * Written by David Flanagan. Copyright (c) 1999 by O'Reilly & Associates.  
+ * You may distribute this source code for non-commercial purposes only.
+ * You may study, modify, and use this example for any purpose, as long as
+ * this notice is retained.  Note that this example is provided "as is",
+ * WITHOUT WARRANTY of any kind either expressed or implied.
+ */
+
+import javax.swing.*;
+import javax.swing.event.*;
+import javax.swing.tree.*;
+import java.io.File;
+
+public class FileTreeDemo {
+  public static void main(String[] args) {
+    // Figure out where in the filesystem to start displaying
+    File root;
+    if (args.length > 0) root = new File(args[0]);
+    else root = new File(System.getProperty("user.home"));
+
+    // Create a TreeModel object to represent our tree of files
+    FileTreeModel model = new FileTreeModel(root);
+
+    // Create a JTree and tell it to display our model
+    JTree tree = new JTree();
+    tree.setModel(model);
+
+    // The JTree can get big, so allow it to scroll.
+    JScrollPane scrollpane = new JScrollPane(tree);
+    
+    // Display it all in a window and make the window appear
+    JFrame frame = new JFrame("FileTreeDemo");
+    frame.getContentPane().add(scrollpane, "Center");
+    frame.setSize(400,600);
+    frame.setVisible(true);
+  }
+}
+
+/**
+ * The methods in this class allow the JTree component to traverse
+ * the file system tree, and display the files and directories.
+ **/
+class FileTreeModel implements TreeModel {
+  // We specify the root directory when we create the model.
+  protected File root;
+  public FileTreeModel(File root) { this.root = root; }
+
+  // The model knows how to return the root object of the tree
+  public Object getRoot() { return root; }
+
+  // Tell JTree whether an object in the tree is a leaf or not
+  public boolean isLeaf(Object node) {  return ((File)node).isFile(); }
+
+  // Tell JTree how many children a node has
+  public int getChildCount(Object parent) {
+    String[] children = ((File)parent).list();
+    if (children == null) return 0;
+    return children.length;
+  }
+
+  // Fetch any numbered child of a node for the JTree.
+  // Our model returns File objects for all nodes in the tree.  The
+  // JTree displays these by calling the File.toString() method.
+  public Object getChild(Object parent, int index) {
+    String[] children = ((File)parent).list();
+    if ((children == null) || (index >= children.length)) return null;
+    return new File((File) parent, children[index]);
+  }
+
+  // Figure out a child's position in its parent node.
+  public int getIndexOfChild(Object parent, Object child) {
+    String[] children = ((File)parent).list();
+    if (children == null) return -1;
+    String childname = ((File)child).getName();
+    for(int i = 0; i < children.length; i++) {
+      if (childname.equals(children[i])) return i;
+    }
+    return -1;
+  }
+
+  // This method is only invoked by the JTree for editable trees.  
+  // This TreeModel does not allow editing, so we do not implement 
+  // this method.  The JTree editable property is false by default.
+  public void valueForPathChanged(TreePath path, Object newvalue) {}
+
+  // Since this is not an editable tree model, we never fire any events,
+  // so we don't actually have to keep track of interested listeners.
+  public void addTreeModelListener(TreeModelListener l) {}
+  public void removeTreeModelListener(TreeModelListener l) {}
+}