org.eclipse.nebula.widgets.nattable.core/src/org/eclipse/nebula/widgets/nattable/group/action/ColumnHeaderReorderDragMode.java

/*******************************************************************************
 * Copyright (c) 2012, 2020 Original authors and others.
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     Original authors and others - initial API and implementation
 ******************************************************************************/
package org.eclipse.nebula.widgets.nattable.group.action;

import org.eclipse.nebula.widgets.nattable.group.ColumnGroupModel;
import org.eclipse.nebula.widgets.nattable.group.ColumnGroupUtils;
import org.eclipse.nebula.widgets.nattable.layer.ILayer;
import org.eclipse.nebula.widgets.nattable.reorder.action.ColumnReorderDragMode;
import org.eclipse.nebula.widgets.nattable.util.GUIHelper;

/**
 * Extends the regular column drag functionality to work with Column groups. It
 * does the following checks:
 * <ol>
 * <li>Checks that the destination is not part of a Unbreakable column
 * group</li>
 * <li>Checks if the destination is between two adjoining column groups</li>
 * </ol>
 */
public class ColumnHeaderReorderDragMode extends ColumnReorderDragMode {

    private final ColumnGroupModel model;

    public ColumnHeaderReorderDragMode(ColumnGroupModel model) {
        this.model = model;
    }

    @Override
    public boolean isValidTargetColumnPosition(ILayer natLayer,
            int fromGridColumnPosition, int toGridColumnPosition) {
        if (this.currentEvent != null) {
            // if this method was triggered by a mouse event, we determine the
            // to column position by the event
            // if there is no current mouse event referenced it means the
            // reorder is triggered programmatically
            toGridColumnPosition = natLayer
                    .getColumnPositionByX(this.currentEvent.x);
        }
        int toColumnIndex = natLayer
                .getColumnIndexByPosition(toGridColumnPosition);
        int fromColumnIndex = natLayer
                .getColumnIndexByPosition(fromGridColumnPosition);

        // Allow moving within the unbreakable group
        if (this.model.isPartOfAnUnbreakableGroup(fromColumnIndex)) {
            return ColumnGroupUtils.isInTheSameGroup(fromColumnIndex,
                    toColumnIndex, this.model);
        }

        boolean betweenTwoGroups = false;
        if (this.currentEvent != null) {
            int minX = this.currentEvent.x
                    - GUIHelper.DEFAULT_RESIZE_HANDLE_SIZE;
            int maxX = this.currentEvent.x
                    + GUIHelper.DEFAULT_RESIZE_HANDLE_SIZE;
            betweenTwoGroups = ColumnGroupUtils.isBetweenTwoGroups(natLayer,
                    minX, maxX, this.model);
        }

        return (!this.model.isPartOfAnUnbreakableGroup(toColumnIndex))
                || betweenTwoGroups;
    }
}