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Tip revision: 759bd8995e51c4e40aa72fd5657d5e6e04c6da89 authored by Software Heritage on 04 February 2020, 13:44:27 UTC
hal: Deposit 405 in collection hal
Tip revision: 759bd89
ListTransferHandler.java
package extra;

/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  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 Sun Microsystems nor 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.
 */

/*
 * ListTransferHandler.java is used by the DropDemo example.
 */
import javax.swing.*;
import java.awt.datatransfer.*;

public class ListTransferHandler extends TransferHandler {
	private static final long serialVersionUID = 1L;
	private int[] indices = null;
	private int addIndex = -1; // Location where items were added
	private int addCount = 0; // Number of items added.

	@Override
	public boolean canImport(TransferHandler.TransferSupport info) {
		// Check for String flavor
		if (!info.isDataFlavorSupported(DataFlavor.stringFlavor)) {
			return false;
		}
		return true;
	}

	@Override
	protected Transferable createTransferable(JComponent c) {
		return new StringSelection(exportString(c));
	}

	@Override
	public int getSourceActions(JComponent c) {
		return TransferHandler.COPY_OR_MOVE;
	}

	@Override
	public boolean importData(TransferHandler.TransferSupport info) {
		if (!info.isDrop()) {
			return false;
		}

		JList list = (JList) info.getComponent();
		DefaultListModel listModel = (DefaultListModel) list.getModel();
		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;
		}

		// Perform the actual import.
		if (insert) {
			listModel.add(index, data);
		} else {
			listModel.set(index, data);
		}
		return true;
	}

	@Override
	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) {
		JList list = (JList) c;
		indices = list.getSelectedIndices();
		Object[] values = list.getSelectedValues();

		StringBuffer buff = new StringBuffer();

		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) {
		JList target = (JList) c;
		DefaultListModel listModel = (DefaultListModel) target.getModel();
		int index = target.getSelectedIndex();

		// 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;
		}

		int max = listModel.getSize();
		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++) {
			listModel.add(index++, values[i]);
		}
	}

	// 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) {
			JList source = (JList) c;
			DefaultListModel model = (DefaultListModel) source.getModel();
			// 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;
					}
				}
			}
			for (int i = indices.length - 1; i >= 0; i--) {
				model.remove(indices[i]);
			}
		}
		indices = null;
		addCount = 0;
		addIndex = -1;
	}
}
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