/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.

 */

package com.oracle.solaris.vp.util.swing;

import java.util.*;

import javax.swing.DefaultListSelectionModel;

public class ValidatingListSelectionModel extends DefaultListSelectionModel {

    //

    // Instance data

    //

    private List<Integer> selection = new LinkedList<Integer>();

    private int anchor = -1;

    private int lead = -1;

    //

    // DefaultListSelectionModel methods

    //

    @Override

    protected void fireValueChanged(int firstIndex, int lastIndex,

	boolean isAdjusting) {

	if (!isAdjusting) {

	    if (validateSelection()) {

		save();

		super.fireValueChanged(firstIndex, lastIndex, isAdjusting);

	    } else {

		setValueIsAdjusting(true);

		revert();

		setValueIsAdjusting(false);

	    }

	}

    }

    //

    // ValidatingListSelectionModel methods

    //

    /**

     * Verifies that the current selection is valid.  This default

     * implementation returns {@code true}.

     *

     * @return	    {@code true} if the selection is valid, {@code false}

     *		    otherwise

     */

    protected boolean validateSelection() {

	return true;

    }

    protected void revert() {

	clearSelection();

	for (int i = 0, n = selection.size(); i < n; i++) {

	    int first = selection.get(i);

	    int last = first;

	    if (i < n - 1 && selection.get(i + 1) == null) {

		i += 2;

		last = selection.get(i);

	    }

	    addSelectionInterval(first, last);

	}

	setAnchorSelectionIndex(anchor);

	setLeadSelectionIndex(lead);

    }

    @SuppressWarnings({"fallthrough"})

    protected void save() {

	anchor = getAnchorSelectionIndex();

	lead = getLeadSelectionIndex();

	int min = getMinSelectionIndex();

	int max = getMaxSelectionIndex();

	selection.clear();

	if (min < 0 || max < 0) {

	    return;

	}

	for (int i = min; i <= max; i++) {

	    if (isSelectedIndex(i)) {

		int first = i;

		selection.add(first);

		for (i++; i <= max && isSelectedIndex(i); i++);

		int last = i - 1;

		switch (last - first) {

		default:

		    selection.add(null);

		case 1:

		    selection.add(last);

		case 0:

		}

	    }

	}

    }

}