I have a JTree implementation for directories in the file system. The problem I have is that when a directory is removed or renamed, the tree still shows the directory in it’s parent. The parent tree seems not to be updated for any changes once a node has been expanded.
The model I have written does not cache (I have commented out what limited caching it did have) – it’s like the JTree itself has cached the node.
The code (the model is a nested subclass):
public class FileSystemTree extends JTree { // ***************************************************************************** // INSTANCE CREATE/DELETE // ***************************************************************************** public FileSystemTree() { this(new Model(null,null,null)); } public FileSystemTree(String startPath) { this(new Model(startPath,null,null)); } public FileSystemTree(FileSelector inc, FileSelector exc) { this(new Model(null,inc,exc)); } public FileSystemTree(String startPath, FileSelector inc, FileSelector exc) { this(new Model(startPath,inc,exc)); } private FileSystemTree(Model model) { super(model); //setLargeModel(true); setRootVisible(false); setShowsRootHandles(true); putClientProperty('JTree.lineStyle','Angled'); } // ***************************************************************************** // INSTANCE METHODS - ACCESSORS // ***************************************************************************** public Object getRoot() { return getModel().getRoot(); } // ***************************************************************************** // INSTANCE METHODS // ***************************************************************************** public String convertValueToText(Object value,boolean selected,boolean expanded,boolean leaf,int row,boolean hasFocus) { File fil=(File)value; return (fil.getName().length()!=0 ? fil.getName() : fil.getPath()); } // ***************************************************************************** // STATIC NESTED CLASSES - SUPPORTING MODEL // ***************************************************************************** static class Model extends Object implements TreeModel, FilenameFilter { private File root; // tree root //ivate Map cache; // caches child counts for directories private File[] fsRoots; // copy of file system roots private FileSelector include; // inclusion selector private FileSelector exclude; // exclusion selector private java.util.List listeners=new ArrayList(); public Model(String roo, FileSelector inc, FileSelector exc) { super(); root=(roo==null ? DRIVES : new File(roo)); //cache=new HashMap(); fsRoots=(root==DRIVES ? rootList() : null); include=inc; exclude=exc; } // ***************************************************************************** // METHODS - MODEL // ***************************************************************************** public Object getRoot() { return root; } public Object getChild(Object parent, int index) { File dir=(File)parent; if(dir==DRIVES) { File[] chl=fsRoots; //rootList(); return (index<chl.length ? chl[index] : null); } else { String[] chl=dirList(dir); return (index<chl.length ? new File(dir,chl[index]) : null); } } public int getChildCount(Object parent) { File dir=(File)parent; //Integer cch=(Integer)cache.get(dir); //if(cch!=null) { // return cch.intValue(); // } if(dir==DRIVES) { return fsRoots.length; //rootList().length; } else if(dir.isDirectory()) { return dirList(dir).length; } else { return 0; } } public boolean isLeaf(Object node) { return((File)node).isFile(); } public void valueForPathChanged(TreePath path, Object newValue) { } public int getIndexOfChild(Object parent, Object child) { File dir=(File)parent; File fse=(File)child; if(dir==DRIVES) { File[] ca=fsRoots; //rootList(); for(int xa=0; xa<ca.length; xa++) { if(fse.equals(ca[xa])) { return xa; } } } else { String[] ca=dirList(dir); for(int xa=0; xa<ca.length; ++xa) { if(fse.getName().equals(ca[xa])) { return xa; } } } return -1; } private File[] rootList() { File[] lst=File.listRoots(); if(lst==null) { lst=new File[0]; } //cache.put(DRIVES,new Integer(lst.length)); return lst; } private String[] dirList(File dir) { String[] lst=dir.list(this); if(lst==null) { lst=new String[0]; } //cache.put(dir,new Integer(lst.length)); return lst; } // ***************************************************************************** // METHODS - FILENAME FILTER // ***************************************************************************** public boolean accept(File dir, String nam) { return ((include==null || include.accept(dir,nam)) && (exclude==null || !exclude.accept(dir,nam))); } // ***************************************************************************** // METHODS - LISTENER // ***************************************************************************** public void addTreeModelListener(TreeModelListener listener) { if(listener != null && !listeners.contains(listener)) { listeners.add(listener); } } public void removeTreeModelListener(TreeModelListener listener) { if(listener != null) { listeners.remove(listener); } } public void fireTreeNodesChanged(TreeModelEvent evt) { Iterator itr=listeners.iterator(); while(itr.hasNext()) { TreeModelListener listener=(TreeModelListener)itr.next(); listener.treeNodesChanged(evt); } } public void fireTreeNodesInserted(TreeModelEvent evt) { Iterator itr=listeners.iterator(); while(itr.hasNext()) { TreeModelListener listener=(TreeModelListener)itr.next(); listener.treeNodesInserted(evt); } } public void fireTreeNodesRemoved(TreeModelEvent evt) { Iterator itr=listeners.iterator(); while(itr.hasNext()) { TreeModelListener listener=(TreeModelListener)itr.next(); listener.treeNodesRemoved(evt); } } public void fireTreeStructureChanged(TreeModelEvent evt) { Iterator itr=listeners.iterator(); while(itr.hasNext()) { TreeModelListener listener=(TreeModelListener)itr.next(); listener.treeStructureChanged(evt); } } } // END INNER CLASS // ***************************************************************************** // STATIC PROPERTIES // ***************************************************************************** static private final File DRIVES=new File('*DRIVES'); // marker for listing file system drives } // END PUBLIC CLASS
The model is responsible for notifying the listeners of any modification in the tree structure. The tree will not refresh itself in absence of such a notification.