EDIT

eu.etaxonomy.taxeditor.navigation/src/main/java/eu/etaxonomy/taxeditor/navigation/navigator/TreeNodeDropAdapterAssistant.java -text

         <dropAssistant

               class="eu.etaxonomy.taxeditor.navigation.navigator.TreeNodeDropAdapterAssistant"

               id="eu.etaxonomy.taxeditor.navigation.navigator.dropassistant">

            <possibleDropTargets></possibleDropTargets>

         </dropAssistant>

               class="eu.etaxonomy.taxeditor.navigation.navigator.TreeNodeDropAdapterAssistant"

// $Id$

/**

* Copyright (C) 2007 EDIT

* European Distributed Institute of Taxonomy 

* http://www.e-taxonomy.eu

* 

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.taxeditor.navigation.navigator;

import java.util.HashSet;

import java.util.Iterator;

import java.util.Set;

import org.apache.log4j.Logger;

import org.eclipse.core.commands.operations.IUndoContext;

import org.eclipse.core.runtime.IStatus;

import org.eclipse.core.runtime.Status;

import org.eclipse.jface.dialogs.MessageDialog;

import org.eclipse.jface.util.LocalSelectionTransfer;

import org.eclipse.jface.viewers.ISelection;

import org.eclipse.jface.viewers.TreeSelection;

import org.eclipse.swt.dnd.DropTargetEvent;

import org.eclipse.swt.dnd.TransferData;

import org.eclipse.ui.navigator.CommonDropAdapter;

import org.eclipse.ui.navigator.CommonDropAdapterAssistant;

import eu.etaxonomy.cdm.model.common.CdmBase;

import eu.etaxonomy.cdm.model.taxon.ITreeNode;

import eu.etaxonomy.cdm.model.taxon.TaxonNode;

import eu.etaxonomy.taxeditor.navigation.NavigationUtil;

import eu.etaxonomy.taxeditor.navigation.navigator.operation.MoveTaxonOperation;

import eu.etaxonomy.taxeditor.operation.AbstractPostOperation;

import eu.etaxonomy.taxeditor.operation.IPostOperationEnabled;

/**

 * <p>TaxonNodeDropAdapterAssistant class.</p>

 *

 * @author p.ciardelli

 * @created 03.06.2009

 * @version 1.0

 */

public class TreeNodeDropAdapterAssistant extends CommonDropAdapterAssistant implements IPostOperationEnabled{

	private static final Logger logger = Logger

			.getLogger(TreeNodeDropAdapterAssistant.class);

	/** Constant <code>ID="eu.etaxonomy.taxeditor.navigation.navig"{trunked}</code> */

	public static final String ID = "eu.etaxonomy.taxeditor.navigation.navigator.dropassistant"; //$NON-NLS-1$

	/* (non-Javadoc)

	 * @see org.eclipse.ui.navigator.CommonDropAdapterAssistant#handleDrop(org.eclipse.ui.navigator.CommonDropAdapter, org.eclipse.swt.dnd.DropTargetEvent, java.lang.Object)

	 */

	/** {@inheritDoc} */

	@Override

	public IStatus handleDrop(CommonDropAdapter dropAdapter,

			DropTargetEvent dropTargetEvent, Object target) {

		if (target instanceof ITreeNode) {

			Set<TaxonNode> taxonNodes = getSelectedTaxa();

			ITreeNode targetTreeNode = (ITreeNode) target;

			if(taxonNodes != null)

				return moveTaxon(taxonNodes, targetTreeNode);

		}

		return Status.CANCEL_STATUS;

	}

	private Set<TaxonNode> getSelectedTaxa(){

		HashSet<TaxonNode> taxonNodes = new HashSet<TaxonNode>();		

		ISelection selection = LocalSelectionTransfer.getTransfer().getSelection();

		if (selection instanceof TreeSelection) {

			Iterator selectionIterator = ((TreeSelection) selection).iterator();

			while (selectionIterator.hasNext()){

				Object object = selectionIterator.next();

				if(object instanceof TaxonNode){

					TaxonNode taxonNode = (TaxonNode) object;

					taxonNodes.add(taxonNode);

				}

			}

		}

		return taxonNodes.size() > 0 ? taxonNodes : null;

	}

	/* (non-Javadoc)

	 * @see org.eclipse.ui.navigator.CommonDropAdapterAssistant#validateDrop(java.lang.Object, int, org.eclipse.swt.dnd.TransferData)

	 */

	/** {@inheritDoc} */

	@Override

	public IStatus validateDrop(Object target, int operation,

			TransferData transferType) {	

		if (target instanceof ITreeNode) {

			// do not allow to drop onto itself

			for(TaxonNode taxonNode : getSelectedTaxa()){

				if (taxonNode.equals(target)) {

					return Status.CANCEL_STATUS;

				}

			}

			return Status.OK_STATUS;

		}		

		return Status.CANCEL_STATUS;

	}

	/**

	 * @param childTaxonNode

	 * @param parentTaxon

	 * @return

	 */

	private IStatus moveTaxon(Set<TaxonNode> taxonNodes, ITreeNode targetITreeNode) {

		TaxonNavigator taxonNavigator;

		taxonNavigator = (TaxonNavigator) NavigationUtil.showView(TaxonNavigator.ID);

		if(targetITreeNode instanceof TaxonNode){

			TaxonNode targetTaxonNode = (TaxonNode) targetITreeNode;

//			for(TaxonNode taxonNode : taxonNodes){

//				if (taxonNode.equals(targetTaxonNode)) {

//					return Status.CANCEL_STATUS;

//				}

//			}

			// Make sure parent taxon does not have unsaved changes

			if (NavigationUtil.isDirty(targetTaxonNode)){

				MessageDialog.openWarning(NavigationUtil.getShell(), "Unsaved Parent Taxon", "There are unsaved " +

				"changes in the parent taxon. Pleas save first.");

				return Status.CANCEL_STATUS;

			}

			// Make sure parentTaxon is not the drop target

//			if (!childTaxonNode.isTopmostNode() && childTaxonNode.getParent().equals(targetTaxonNode)){

//				return Status.CANCEL_STATUS;

//			}

			// Make sure taxon is not being dropped onto itself

//			if (childTaxonNode.equals(targetTaxonNode)) {

//				return Status.CANCEL_STATUS;

//			}

		}	

		IUndoContext workspaceUndoContext = NavigationUtil.getWorkbenchUndoContext();

		if (workspaceUndoContext == null) {

			logger.error("Workspace undo context is null. DND operation cancelled");

			return Status.CANCEL_STATUS;

		}

		AbstractPostOperation operation = new MoveTaxonOperation

				("Move Taxon", workspaceUndoContext, taxonNodes, targetITreeNode, this, taxonNavigator);

		NavigationUtil.executeOperation(operation);	

		logger.info("Moved taxa to new parent " + targetITreeNode);

		return Status.OK_STATUS;

	}

	/* (non-Javadoc)

	 * @see eu.etaxonomy.taxeditor.operations.IPostOperationEnabled#postOperation(eu.etaxonomy.cdm.model.common.CdmBase)

	 */

	/** {@inheritDoc} */

	public boolean postOperation(CdmBase objectAffectedByOperation) {

		return true;

	}

	/**

	 * <p>onComplete</p>

	 *

	 * @return a boolean.

	 */

	public boolean onComplete() {

		// TODO Auto-generated method stub

		return false;

	}

}