com.aptana.ide.search.epl.ResourceTransferDragAdapter.java Source code

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Here is the source code for com.aptana.ide.search.epl.ResourceTransferDragAdapter.java

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/*******************************************************************************
 * Copyright (c) 2000, 2006 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package com.aptana.ide.search.epl;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.util.TransferDragSourceListener;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.swt.dnd.DragSourceAdapter;
import org.eclipse.swt.dnd.DragSourceEvent;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.ui.part.ResourceTransfer;

/**
 * A drag adapter that transfers the current selection as </code>
 * IResource</code>. Only those elements in the selection are part 
 * of the transfer which can be converted into an <code>IResource
 * </code>.
 */
public class ResourceTransferDragAdapter extends DragSourceAdapter implements TransferDragSourceListener {

    private ISelectionProvider fProvider;

    /**
     * Creates a new ResourceTransferDragAdapter for the given selection
     * provider.
     * 
     * @param provider the selection provider to access the viewer's selection
     */
    public ResourceTransferDragAdapter(ISelectionProvider provider) {
        fProvider = provider;
        Assert.isNotNull(fProvider);
    }

    public Transfer getTransfer() {
        return ResourceTransfer.getInstance();
    }

    public void dragStart(DragSourceEvent event) {
        event.doit = convertSelection().size() > 0;
    }

    public void dragSetData(DragSourceEvent event) {
        List resources = convertSelection();
        event.data = resources.toArray(new IResource[resources.size()]);
    }

    public void dragFinished(DragSourceEvent event) {
        if (!event.doit)
            return;
    }

    private List convertSelection() {
        ISelection s = fProvider.getSelection();
        if (!(s instanceof IStructuredSelection))
            return Collections.EMPTY_LIST;
        IStructuredSelection selection = (IStructuredSelection) s;
        List result = new ArrayList(selection.size());
        for (Iterator iter = selection.iterator(); iter.hasNext();) {
            Object element = iter.next();
            if (element instanceof IResource) {
                result.add(element);
            }
        }
        return result;
    }
}