eu.geclipse.ui.internal.transfer.SelectionTransferDragAdapter.java Source code

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Here is the source code for eu.geclipse.ui.internal.transfer.SelectionTransferDragAdapter.java

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/*****************************************************************************
 * Copyright (c) 2006, 2007 g-Eclipse Consortium 
 * 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
 *
 * Initial development of the original code was made for the
 * g-Eclipse project founded by European Union
 * project number: FP6-IST-034327  http://www.geclipse.eu/
 *
 * Contributors:
 *    Mathias Stuempert - initial API and implementation
 *****************************************************************************/

package eu.geclipse.ui.internal.transfer;

import java.util.Iterator;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.util.TransferDragSourceListener;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.swt.dnd.DragSourceEvent;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.ui.views.navigator.LocalSelectionTransfer;

import eu.geclipse.core.model.IGridElement;
import eu.geclipse.ui.views.GridModelViewPart;

/**
 * Transfer drag adapter for selections specialised for the transfer of
 * Grid elements.
 */
public class SelectionTransferDragAdapter implements TransferDragSourceListener {

    private GridModelViewPart view;

    /**
     * Construct a new transfer drag adapter for the specified model view.
     * 
     * @param view The {@link GridModelViewPart} for which to create
     * this transfer drag adapter.
     */
    public SelectionTransferDragAdapter(final GridModelViewPart view) {
        Assert.isNotNull(view);
        this.view = view;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.util.TransferDragSourceListener#getTransfer()
     */
    public Transfer getTransfer() {
        return LocalSelectionTransfer.getInstance();
    }

    /* (non-Javadoc)
     * @see org.eclipse.swt.dnd.DragSourceListener#dragFinished(org.eclipse.swt.dnd.DragSourceEvent)
     */
    public void dragFinished(final DragSourceEvent event) {
        // TODO mathias - implement move functionality
        LocalSelectionTransfer.getInstance().setSelection(null);
        LocalSelectionTransfer.getInstance().setSelectionSetTime(0);
    }

    /* (non-Javadoc)
     * @see org.eclipse.swt.dnd.DragSourceListener#dragSetData(org.eclipse.swt.dnd.DragSourceEvent)
     */
    public void dragSetData(final DragSourceEvent event) {
        event.data = LocalSelectionTransfer.getInstance().getSelection();
    }

    /* (non-Javadoc)
     * @see org.eclipse.swt.dnd.DragSourceListener#dragStart(org.eclipse.swt.dnd.DragSourceEvent)
     */
    public void dragStart(final DragSourceEvent event) {
        ISelection selection = this.view.getViewer().getSelection();
        event.doit = isDragable(selection);
        if (event.doit) {
            LocalSelectionTransfer.getInstance().setSelection(selection);
            LocalSelectionTransfer.getInstance().setSelectionSetTime(event.time & 0xFFFFFFFFL);
        }
    }

    /**
     * Determines if the specified selection contains only dragable elements.
     * 
     * @param selection The selection to be tested.
     * @return True if {@link GridModelViewPart#isDragSource(IGridElement)} returns
     * true for all elements contained in the specified selection.
     */
    protected boolean isDragable(final ISelection selection) {
        boolean result = true;
        if (!selection.isEmpty() && (selection instanceof IStructuredSelection)) {
            IStructuredSelection sSelection = (IStructuredSelection) selection;
            Iterator<?> iter = sSelection.iterator();
            while (iter.hasNext() && result) {
                Object obj = iter.next();
                if (!(obj instanceof IGridElement) || !this.view.isDragSource((IGridElement) obj)) {
                    result = false;
                }
            }
        }
        return result;
    }

}