com.rcpcompany.uibindings.internal.utils.UIHandlerUtils.java Source code

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Here is the source code for com.rcpcompany.uibindings.internal.utils.UIHandlerUtils.java

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/*******************************************************************************
 * Copyright (c) 2006-2013 The RCP Company and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     The RCP Company - initial API and implementation
 *******************************************************************************/
package com.rcpcompany.uibindings.internal.utils;

import org.eclipse.core.databinding.observable.list.IObservableList;
import org.eclipse.core.runtime.Assert;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.jface.viewers.ColumnViewer;
import org.eclipse.jface.viewers.ColumnViewerEditor;
import org.eclipse.jface.viewers.ViewerCell;

import com.rcpcompany.uibindings.IViewerBinding;
import com.rcpcompany.uibindings.internal.Activator;
import com.rcpcompany.utils.logging.LogUtils;

/**
 * Various utility methods for use in handler and expressions/property testers.
 * 
 * @author Tonny Madsen, The RCP Company
 */
public final class UIHandlerUtils {
    private UIHandlerUtils() {
    }

    /**
     * Moves the specified element in the viewer of the binding.
     * 
     * @param vb the viewer binding
     * @param element the element to move
     * @param delta the amount to move
     * @param testOnly <code>true</code> if the move should only be tested for, but not performed
     * @return <code>true</code> if the element could be moved
     */
    public static boolean moveElement(IViewerBinding vb, EObject element, int delta, boolean testOnly) {
        if (Activator.getDefault().TRACE_NAVIGATION_VIEWER) {
            LogUtils.debug(vb, "delta=" + delta + ", testOnly=" + testOnly + ", element=" + element);
        }

        Assert.isNotNull(vb);
        if (element == null)
            return false;

        final ColumnViewer viewer = vb.getViewer();
        /*
         * Don't move if there are any sorter or filters installed as these negates the visual
         * effect.
         */
        if (viewer.getComparator() != null || viewer.getFilters().length > 0)
            return false;

        // The list of objects
        final IObservableList list = vb.getList();

        // Old position
        final int oldPosition = list.indexOf(element);
        if (oldPosition == -1)
            return false;

        // New position
        int newPosition = oldPosition + delta;
        if (newPosition < 0) {
            newPosition = 0;
        }
        if (newPosition >= list.size()) {
            newPosition = list.size() - 1;
        }

        // Can not be moved?
        if (oldPosition == newPosition)
            return false;

        // Move it
        if (!testOnly) {
            final ColumnViewerEditor editor = viewer.getColumnViewerEditor();
            final ViewerCell oldFocusCell = editor.getFocusCell();

            list.move(newPosition, oldPosition);

            vb.setFocus(oldFocusCell.getColumnIndex(), element);
            // ((Table) viewer.getControl()).setSelection(newPosition);
        }
        return true;
    }
}