Mayumi Blogger Template

/**
 *This is a simple Windows File System Explorer program written in java.
 *@author Tapas kumar jena
 *@mail tapas.friends@gmail.com
 */

import java.awt.Component;
import java.io.File;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.NoSuchElementException;

import javax.swing.Icon;
import javax.swing.JApplet;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.UIManager;
import javax.swing.filechooser.FileSystemView;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.TreeNode;

/*
 * This prograam will read your local file system and show you in a tree structure.
 */
public class ExplorerApplet extends JApplet {

 File[] roots;
 FileTreeNode rootTreeNode;
 private JTree tree;
 protected static FileSystemView fsv = FileSystemView.getFileSystemView();
 
 public void init() {
  try {
   UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
   //UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
  }catch (Exception e) {
   e.printStackTrace();
  }
  roots = File.listRoots();
  rootTreeNode = new FileTreeNode(roots);
  tree = new JTree(rootTreeNode);
  tree.setCellRenderer(new FileTreeCellRenderer());
  tree.setName("My Computer");
  tree.setRootVisible(true);
  final JScrollPane jsp = new JScrollPane(tree);
  add(jsp);
 }
 
 private static class FileTreeCellRenderer extends DefaultTreeCellRenderer {
  private Map iconCache = new HashMap();
  private Map rootNameCache = new HashMap();
  
  public Component getTreeCellRendererComponent(JTree tree, Object value,boolean sel, boolean expanded, boolean leaf, int row,boolean hasFocus) {
   FileTreeNode ftn = (FileTreeNode) value;
   File file = ftn.file;
   String filename = "";
   if (file != null) {
    if (ftn.isFileSystemRoot) {
     filename = (String) this.rootNameCache.get(file);
     if (filename == null) {
      filename = fsv.getSystemDisplayName(file);
      this.rootNameCache.put(file, filename);
     }
    }else {
     filename = file.getName();
    }
   }
   JLabel result = (JLabel) super.getTreeCellRendererComponent(tree,filename, sel, expanded, leaf, row, hasFocus);
   if (file != null) {
    Icon icon = (Icon)this.iconCache.get(filename);
    if (icon == null) {
     icon = fsv.getSystemIcon(file);
     this.iconCache.put(filename, icon);
    }
    result.setIcon(icon);
   }
   return result;
  }
 }
 
 private static class FileTreeNode implements TreeNode {
  private File file;
  private File[] children;
  private TreeNode parent;
  private boolean isFileSystemRoot;
  
  public FileTreeNode(File file, boolean isFileSystemRoot, TreeNode parent) {
   this.file = file;
   this.isFileSystemRoot = isFileSystemRoot;
   this.parent = parent;
   this.children = this.file.listFiles();
   if (this.children == null)
    this.children = new File[0];
  }
  
  public FileTreeNode(File[] children) {
   this.file = null;
   this.parent = null;
   this.children = children;
  }
  
  public Enumeration children() {
   final int elementCount = this.children.length;
   return new Enumeration() {
   int count = 0;
   public boolean hasMoreElements() {
   return this.count < elementCount;
  }
   
  public File nextElement() {
   if (this.count < elementCount) {
    return FileTreeNode.this.children[this.count++];
   }
   throw new NoSuchElementException("Vector Enumeration");
  }};
  }
  
  public boolean getAllowsChildren() {
   return true;
  }
  
  public TreeNode getChildAt(int childIndex) {
   return new FileTreeNode(this.children[childIndex],
   this.parent == null, this);
  }
  
  public int getChildCount() {
   return this.children.length;
  }
  
  public int getIndex(TreeNode node) {
   FileTreeNode ftn = (FileTreeNode) node;
   for (int i = 0; i < this.children.length; i++) {
    if (ftn.file.equals(this.children[i]))
     return i;
   }
   return -1;
  }
  
  public TreeNode getParent() {
   return this.parent;
  }
  
  public boolean isLeaf() {
   return (this.getChildCount() == 0);
  }
 }
}