package org.apache.log4j.chainsaw.dnd;
import org.apache.log4j.Logger;
import java.awt.datatransfer.DataFlavor;
import java.awt.Color;
import java.awt.datatransfer.Transferable;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DropTarget;
import java.awt.dnd.DropTargetDragEvent;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.dnd.DropTargetEvent;
import java.awt.dnd.DropTargetListener;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.swing.BorderFactory;
import javax.swing.JComponent;
/**
* This class provides all the functionality to work out when files are dragged onto
* a particular JComponent instance, and then notifies listeners via
* the standard PropertyChangesListener semantics to indicate that a list of
* files have been dropped onto the target.
*
* If you wish to know whan the files have been dropped, subscribe to the "fileList" property change.
*
* @author psmith
*
*/
public class FileDnDTarget implements DropTargetListener{
/**
* Logger for this class
*/
private static final Logger LOG = Logger.getLogger(FileDnDTarget.class);
protected int acceptableActions = DnDConstants.ACTION_COPY;
private DropTarget dropTarget;
private List fileList;
private JComponent guiTarget;
private Map dropTargets = new HashMap();
private PropertyChangeSupport propertySupport = new PropertyChangeSupport(this);
/**
*
*/
public FileDnDTarget(JComponent c) {
this.guiTarget = c;
dropTarget = new DropTarget(this.guiTarget, this);
}
public void addDropTargetToComponent(JComponent c){
dropTargets.put(c, new DropTarget(c, this));
}
/**
* @param listener
*/
public void addPropertyChangeListener(PropertyChangeListener listener) {
propertySupport.addPropertyChangeListener(listener);
}
/**
* @param propertyName
* @param listener
*/
public void addPropertyChangeListener(String propertyName,
PropertyChangeListener listener) {
propertySupport.addPropertyChangeListener(propertyName, listener);
}
/**
*
*/
private void decorateComponent() {
// TODO work out a better way of decorating a component
guiTarget.setBorder(BorderFactory.createLineBorder(Color.black));
}
public void dragEnter(DropTargetDragEvent e) {
//LOG.debug(dtde);
if (isDragOk(e) == false) {
e.rejectDrag();
return;
}
decorateComponent();
e.acceptDrag(acceptableActions);
}
public void dragExit(DropTargetEvent dte) {
removeComponentDecoration();
}
public void dragOver(DropTargetDragEvent e) {
//LOG.debug(dtde);
if (isDragOk(e) == false) {
e.rejectDrag();
return;
}
e.acceptDrag(acceptableActions);
}
public void drop(DropTargetDropEvent dtde) {
Transferable transferable = dtde.getTransferable();
LOG.debug(transferable);
dtde.acceptDrop(acceptableActions);
try {
List list = (List)transferable.getTransferData(DataFlavor.javaFileListFlavor);
LOG.debug(list);
setFileList(list);
dtde.getDropTargetContext().dropComplete(true);
removeComponentDecoration();
} catch (Exception e) {
LOG.error("Error with DnD", e);
}
}
public void dropActionChanged(DropTargetDragEvent dtde) {
//LOG.debug(dtde);
}
/**
* @return Returns the fileList.
*/
public final List getFileList() {
return fileList;
}
private boolean isDragOk(DropTargetDragEvent e) {
DataFlavor[] flavors = new DataFlavor[] { DataFlavor.javaFileListFlavor };
DataFlavor chosen = null;
for (int i = 0; i < flavors.length; i++) {
if (e.isDataFlavorSupported(flavors[i])) {
chosen = flavors[i];
break;
}
}
/*
* the src does not support any of the StringTransferable flavors
*/
if (chosen == null) {
return false;
}
// the actions specified when the source
// created the DragGestureRecognizer
int sa = e.getSourceActions();
// we're saying that these actions are necessary
if ((sa & acceptableActions) == 0)
return false;
return true;
}
/**
*
*/
private void removeComponentDecoration() {
this.guiTarget.setBorder(null);
}
/**
* @param listener
*/
public void removePropertyChangeListener(PropertyChangeListener listener) {
propertySupport.removePropertyChangeListener(listener);
}
/**
* @param propertyName
* @param listener
*/
public void removePropertyChangeListener(String propertyName,
PropertyChangeListener listener) {
propertySupport.removePropertyChangeListener(propertyName, listener);
}
/**
* @param fileList The fileList to set.
*/
private final void setFileList(List fileList) {
Object oldValue = this.fileList;
this.fileList = fileList;
propertySupport.firePropertyChange("fileList", oldValue, this.fileList);
}
}