このFile.listRoots()メソッドは、システムのすべてのルート フォルダーを表すファイルの配列を返します。論理ファイルを作成し、これらすべてのルートをそれに追加したいのでFile、引数として受け取るメソッドを呼び出すことができます。
たとえば、次の疑似メソッドがあるとします。
void xyz(final File f) {
// ....
}
final File roots = somekindofwrapper(File.listRoots());
xyz(roots);
要件は、roots上記の疑似コードで、システム上のすべてのルートを含む論理ファイルであることです。これは可能ですか？
import javax.swing.*;
import java.io.File;
public class FileTreeDemo {
public static void main(String[] args) {
try{ UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
}catch(Exception e){
System.out.println("cant done");
}
// Create a JTree and tell it to display our model
JTree tree = new JTree();
// The JTree can get big, so allow it to scroll
JScrollPane scrollpane = new JScrollPane(tree);
// Figure out where in the filesystem to start displaying
File[] roots = File.listRoots();
FileTreeModel model = new FileTreeModel(null);
// for(File root: roots)
// {
model=new FileTreeModel(roots[0]);
tree.setModel(model);
// }
JFrame frame = new JFrame("FileTreeDemo");
frame.getContentPane().add(scrollpane, "Center");
frame.setSize(400,600);
frame.setVisible(true);
}
}
import java.io.File;
import javax.swing.event.TreeModelListener;
import javax.swing.tree.DefaultTreeSelectionModel;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreePath;
import javax.swing.tree.TreeSelectionModel;
public class FileTreeModel extends DefaultTreeSelectionModel implements TreeModel{
// We specify the root directory when we create the model.
protected File root;
public FileTreeModel(File root) { this.root = root;
//setSelectionMode(TreeSelectionModel.DISCONTIGUOUS_TREE_SELECTION);
}
// 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
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 invoked by the JTree only 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) {}
}