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    • org.jdesktop.swingx.demos.xlist.ListTransferHandler Maven / Gradle / Ivy

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    Demonstrating the abilities of the Swing UI Toolkit swingset2 and swingx aka swingset3

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    /*
 * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle or the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 
package org.jdesktop.swingx.demos.xlist;

import java.awt.Component;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.util.List;

import javax.swing.DefaultComboBoxModel;
import javax.swing.DefaultListModel;
import javax.swing.JComponent;
import javax.swing.JList;
import javax.swing.ListModel;
import javax.swing.TransferHandler;

/*
 * ListTransferHandler.java is used by the DropDemo example.
 * copied from https://docs.oracle.com/javase/tutorial/uiswing/dnd/dropmodedemo.html
 * 
 * honor instanceof DefaultListModel and DefaultComboBoxModel as listModel
 */
@SuppressWarnings("serial")
public class ListTransferHandler extends TransferHandler {
	
    private int[] indices = null;
    protected void setIndizes(int[] indizes) {
    	this.indices = indizes;
    }
    private int addIndex = -1; //Location where items were added
    private int addCount = 0;  //Number of items added.
            
    public boolean canImport(TransferHandler.TransferSupport info) {
        // Check for String flavor
        if (!info.isDataFlavorSupported(DataFlavor.stringFlavor)) {
            return false;
        }
        return true;
   }

    protected Transferable createTransferable(JComponent c) {
        return new StringSelection(exportString(c));
    }
    
    public int getSourceActions(JComponent c) {
        return TransferHandler.COPY_OR_MOVE;
    }
    
    public boolean importData(TransferHandler.TransferSupport info) {
        if (!info.isDrop()) {
            return false;
        }

        JList.DropLocation dl = (JList.DropLocation)info.getDropLocation();
        int index = dl.getIndex();
        boolean insert = dl.isInsert();

        // Get the string that is being dropped.
        Transferable t = info.getTransferable();
        String data;
        try {
            data = (String)t.getTransferData(DataFlavor.stringFlavor);
        } 
        catch (Exception e) { return false; }
                        
        Component comp = info.getComponent();
        if(comp instanceof JList list) {
        	ListModel listModel = list.getModel();
        	if(listModel instanceof DefaultListModel) {
        		DefaultListModel model = (DefaultListModel)listModel;
                // Perform the actual import.  
                if (insert) {
                	model.add(index, data);
                } else {
                	model.set(index, data);
                }
                return true;
        	}
        	if(listModel instanceof DefaultComboBoxModel) {
        		DefaultComboBoxModel model = (DefaultComboBoxModel)listModel;
                // Perform the actual import.  
                if (insert || index<0) {
                	model.addElement(data);
                } else {
                	model.insertElementAt(data, index);
                }
                return true;
        	}
        }
        return false;
    }

    protected void exportDone(JComponent c, Transferable data, int action) {
        cleanup(c, action == TransferHandler.MOVE);
    }

    //Bundle up the selected items in the list as a single string, for export.
    protected String exportString(JComponent c) {
    	StringBuffer buff = new StringBuffer();
    	if(c instanceof JList list) {
    		setIndizes(list.getSelectedIndices());
    		List l = list.getSelectedValuesList();
    		Object[] values = new Object[l.size()];
    		l.toArray(values); // fill the array
    		for (int i = 0; i < values.length; i++) {
                Object val = values[i];
                buff.append(val == null ? "" : val.toString());
                if (i != values.length - 1) {
                    buff.append("\n");
                }
    		}
    	}
        return buff.toString();
    }

    //Take the incoming string and wherever there is a newline, 
    //break it into a separate item in the list.
    protected void importString(JComponent c, String str) {
    	int index = -1;
    	int max = 0;
    	ListModel listModel = null;
    	if(c instanceof JList list) {
    		index = list.getSelectedIndex();
    		listModel = list.getModel();
    		max = listModel.getSize();
    	}

        //Prevent the user from dropping data back on itself.
        //For example, if the user is moving items #4,#5,#6 and #7 and
        //attempts to insert the items after item #5, this would
        //be problematic when removing the original items.
        //So this is not allowed.
        if (indices != null && index >= indices[0] - 1 && index <= indices[indices.length - 1]) {
            indices = null;
            return;
        }

        if (index < 0) {
            index = max;
        } else {
            index++;
            if (index > max) {
                index = max;
            }
        }
        addIndex = index;
        String[] values = str.split("\n");
        addCount = values.length;
        for (int i = 0; i < values.length; i++) {
        	if(listModel instanceof DefaultListModel) {
        		DefaultListModel model = (DefaultListModel)listModel;
                model.add(index++, values[i]);
        	}
        	if(listModel instanceof DefaultComboBoxModel) {
        		DefaultComboBoxModel model = (DefaultComboBoxModel)listModel;
        		model.insertElementAt(values[i], index++);
        	}
        }
    }
    
    //If the remove argument is true, the drop has been
    //successful and it's time to remove the selected items 
    //from the list. If the remove argument is false, it
    //was a Copy operation and the original list is left
    //intact.
    protected void cleanup(JComponent c, boolean remove) {
        if (remove && indices != null) {
            //If we are moving items around in the same list, we need to adjust the indices accordingly, 
        	//since those after the insertion point have moved.
            if (addCount > 0) {
                for (int i = 0; i < indices.length; i++) {
                    if (indices[i] > addIndex) {
                        indices[i] += addCount;
                    }
                }
            }
            if(c instanceof JList list) {
            	ListModel listModel = list.getModel();
            	if(listModel instanceof DefaultListModel model) {
                    for (int i = indices.length - 1; i >= 0; i--) {
                        model.remove(indices[i]);
                    }
            	} 
            	if(listModel instanceof DefaultComboBoxModel model) {
                    for (int i = indices.length - 1; i >= 0; i--) {
                        model.removeElement(indices[i]);
                    }
            	} 
            }
        }
        indices = null;
        addCount = 0;
        addIndex = -1;
    }
}
    
    
    
    

    




    
    
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