org.eclipse.gmf.runtime.common.ui.services.dnd/src/org/eclipse/gmf/runtime/common/ui/services/dnd/drop/DelegatingDropTargetAdapter.java - gmf-runtime/org.eclipse.gmf-runtime - Git at Google

 /******************************************************************************
  * Copyright (c) 2002, 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 org.eclipse.gmf.runtime.common.ui.services.dnd.drop;

 import java.util.ArrayList;

 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.dialogs.ErrorDialog;
 import org.eclipse.swt.dnd.DND;
 import org.eclipse.swt.dnd.DropTargetEvent;
 import org.eclipse.swt.dnd.DropTargetListener;
 import org.eclipse.swt.dnd.Transfer;
 import org.eclipse.swt.dnd.TransferData;

 import org.eclipse.gmf.runtime.common.core.util.Log;
 import org.eclipse.gmf.runtime.common.core.util.Trace;
 import org.eclipse.gmf.runtime.common.ui.services.dnd.core.DragDropListenerService;
 import org.eclipse.gmf.runtime.common.ui.services.dnd.core.IListenerContext;
 import org.eclipse.gmf.runtime.common.ui.services.dnd.core.TransferAdapterService;
 import org.eclipse.gmf.runtime.common.ui.services.dnd.internal.CommonUIServicesDNDDebugOptions;
 import org.eclipse.gmf.runtime.common.ui.services.dnd.internal.CommonUIServicesDNDPlugin;
 import org.eclipse.gmf.runtime.common.ui.services.dnd.internal.CommonUIServicesDNDStatusCodes;
 import org.eclipse.gmf.runtime.common.ui.services.dnd.internal.l10n.CommonUIServicesDNDMessages;

 /**
  * This class delegates all the drop target events to the transfer drop target
  * adapter. The transfer adapter delegates to the registered listeners
  *
  * @author Vishy Ramaswamy
  */
 public class DelegatingDropTargetAdapter
 	implements DropTargetListener {

 	/**
 	 * Attribute for the error message
 	 */
 	//private static final String ERROR_MSG = ResourceManager
 	//	.getI18NString("DelegatingDropTargetAdapter.errorMessage"); //$NON-NLS-1$

 	/**
 	 * Attribute for the error message for logging
 	 */
 	//private static final String ERROR_MSG_LOG = ResourceManager
 	//	.getI18NString("DelegatingDropTargetAdapter._ERROR_.errorMessage"); //$NON-NLS-1$

 	/**
 	 * Attribute for the transfer drop target adapters.
 	 */
 	private ITransferDropTargetListener[] adapters = null;

 	/**
 	 * Attribute for the current transfer drop target adapter.
 	 */
 	private ITransferDropTargetListener chosenAdapter = null;

 	/**
 	 * Attribute for the drop target context.
 	 */
 	private final DropTargetContext context;

 	/**
 	 * Attribute for the original drop event type.
 	 */
 	private int origDropType = DND.DROP_NONE;

 	/**
 	 * Attribute for the current drop event type.
 	 */
 	private int currentDropType = DND.DROP_NONE;

 	/**
 	 * Constructor for DelegatingDropTargetAdapter.
 	 *
 	 * @param aContext
 	 *            context information for the drop target
 	 */
 	public DelegatingDropTargetAdapter(DropTargetContext aContext) {
 		super();

 		assert null != aContext : "context information for the drop target cannot be null"; //$NON-NLS-1$
 		this.context = aContext;

 		/* Set the adapters */
 		adapters = getAllTransferAdapters();
 	}

 	/*
 	 * (non-Javadoc)
 	 *
 	 * @see org.eclipse.swt.dnd.DropTargetListener#dragEnter(org.eclipse.swt.dnd.DropTargetEvent)
 	 */
 	public void dragEnter(DropTargetEvent event) {
 		try {
 			/* Set the original drop type */
 			setOrigDropType(event.detail);

 			/* Set the current target and location */
 			getContext().setCurrentTargetAndLocation(event);

 			/*
 			 * Re-Initialize the Transfer Adapters with dynamically with the
 			 * correct context
 			 */
 			initAdapters();

 			/* Set the chosen adapter */
 			setChosenAdapter(event);

 			/* Check if a chosen adapter exists */
 			if (getChosenAdapter() != null) {
 				getChosenAdapter().dragEnter(event);
 			} else {
 				/* Delegate to the drop target */
 				getContext().dragEnter(event);
 			}

 			if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
 				CommonUIServicesDNDDebugOptions.DND)) {
 				String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
 					.getClass().getName()
 					: "No Adapter"; //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"DragEnter::Event detail is " + event.detail); //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"DragEnter::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
 			}
 		} catch (Throwable e) {
 			event.detail = DND.DROP_NONE;
 			handle(e, false);
 		}
 	}

 	/*
 	 * (non-Javadoc)
 	 *
 	 * @see org.eclipse.swt.dnd.DropTargetListener#dragLeave(org.eclipse.swt.dnd.DropTargetEvent)
 	 */
 	public void dragLeave(DropTargetEvent event) {
 		try {
 			/* Check if a chosen adapter exists */
 			if (getChosenAdapter() != null) {
 				getChosenAdapter().dragLeave(event);
 			} else {
 				/* Delegate to the drop target */
 				getContext().dragLeave(event);
 			}

 			if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
 				CommonUIServicesDNDDebugOptions.DND)) {
 				String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
 					.getClass().getName()
 					: "No Adapter"; //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"DragLeave::Event detail is " + event.detail); //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"DragLeave::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
 			}
 		} catch (Throwable e) {
 			handle(e, false);
 		}
 	}

 	/*
 	 * (non-Javadoc)
 	 *
 	 * @see org.eclipse.swt.dnd.DropTargetListener#dragOperationChanged(org.eclipse.swt.dnd.DropTargetEvent)
 	 */
 	public void dragOperationChanged(DropTargetEvent event) {
 		try {
 			/* Set the original drop type */
 			setOrigDropType(event.detail);

 			/* Set the current target and location */
 			getContext().setCurrentTargetAndLocation(event);

 			/* Set the chosen adapter */
 			setChosenAdapter(event);

 			/* Check if a chosen adapter exists */
 			if (getChosenAdapter() != null) {
 				getChosenAdapter().dragOperationChanged(event);
 			} else {
 				/* Delegate to the drop target */
 				getContext().dragOperationChanged(event);
 			}

 			if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
 				CommonUIServicesDNDDebugOptions.DND)) {
 				String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
 					.getClass().getName()
 					: "No Adapter"; //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"DragOperationChanged::Event detail is " + event.detail); //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"DragOperationChanged::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
 			}
 		} catch (Throwable e) {
 			event.detail = DND.DROP_NONE;
 			handle(e, false);
 		}
 	}

 	/*
 	 * (non-Javadoc)
 	 *
 	 * @see org.eclipse.swt.dnd.DropTargetListener#dragOver(org.eclipse.swt.dnd.DropTargetEvent)
 	 */
 	public void dragOver(DropTargetEvent event) {
 		try {
 			/* Set the current target and location */
 			getContext().setCurrentTargetAndLocation(event);

 			/* Set the event detail as the original drop type */
 			event.detail = getOrigDropType();

 			/* Set the chosen adapter */
 			setChosenAdapter(event);

 			/* Check if a chosen adapter exists */
 			if (getChosenAdapter() != null) {
 				getChosenAdapter().dragOver(event);

 				/* Check the event detail */
 				if (event.detail != DND.DROP_NONE) {
 					setCurrentDropType(event.detail);
 				}
 			} else {
 				/* Delegate to the drop target */
 				getContext().dragOver(event);
 			}

 			if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
 				CommonUIServicesDNDDebugOptions.DND)) {
 				String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
 					.getClass().getName()
 					: "No Adapter"; //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"DragOver::Event detail is " + event.detail); //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"DragOver::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
 			}
 		} catch (Throwable e) {
 			event.detail = DND.DROP_NONE;
 			handle(e, false);
 		}
 	}

 	/*
 	 * (non-Javadoc)
 	 *
 	 * @see org.eclipse.swt.dnd.DropTargetListener#drop(org.eclipse.swt.dnd.DropTargetEvent)
 	 */
 	public void drop(DropTargetEvent event) {
 		try {
 			/*
 			 * Save the event detail just in case the event has to be delegated
 			 * to the drop target
 			 */
 			int oldDetail = event.detail;

 			/* Set the current target and location */
 			getContext().setCurrentTargetAndLocation(event);

 			/* Set the event detail as the current drop type */
 			event.detail = getCurrentDropType();

 			/* Set the chosen adapter */
 			setChosenAdapter(event);

 			/* Check if a chosen adapter exists */
 			if (getChosenAdapter() != null) {
 				getChosenAdapter().drop(event);
 			} else {
 				event.detail = oldDetail;

 				/* Delegate to the drop target */
 				getContext().drop(event);
 			}

 			if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
 				CommonUIServicesDNDDebugOptions.DND)) {
 				String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
 					.getClass().getName()
 					: "No Adapter"; //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"Drop::Event detail is " + event.detail); //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"Drop::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
 			}
 		} catch (Throwable e) {
 			event.detail = DND.DROP_NONE;
 			handle(e, true);
 		}
 	}

 	/*
 	 * (non-Javadoc)
 	 *
 	 * @see org.eclipse.swt.dnd.DropTargetListener#dropAccept(org.eclipse.swt.dnd.DropTargetEvent)
 	 */
 	public void dropAccept(DropTargetEvent event) {
 		try {
 			/*
 			 * Save the event detail just in case the event has to be delegated
 			 * to the drop target
 			 */
 			int oldDetail = event.detail;

 			/* Set the current target and location */
 			getContext().setCurrentTargetAndLocation(event);

 			/* Set the event detail as the original drop type */
 			event.detail = getCurrentDropType();

 			/* Set the chosen adapter */
 			setChosenAdapter(event);

 			/* Check if a chosen adapter exists */
 			if (getChosenAdapter() != null) {
 				getChosenAdapter().dropAccept(event);

 				/* Check the event detail */
 				if (event.detail != getCurrentDropType()) {
 					setCurrentDropType(event.detail);
 				}
 			} else {
 				event.detail = oldDetail;

 				/* Delegate to the drop target */
 				getContext().dropAccept(event);
 			}

 			if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
 				CommonUIServicesDNDDebugOptions.DND)) {
 				String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
 					.getClass().getName()
 					: "No Adapter"; //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"DropAccept::Event detail is " + event.detail); //$NON-NLS-1$
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"DropAccept::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
 			}
 		} catch (Throwable e) {
 			event.detail = DND.DROP_NONE;
 			handle(e, false);
 		}
 	}

 	/**
 	 * Returns the adapters.
 	 *
 	 * @return ITransferDropTargetListener[]
 	 */
 	private ITransferDropTargetListener[] getAdapters() {
 		return adapters;
 	}

 	/**
 	 * Returns the drop target context.
 	 *
 	 * @return DropTargetContext
 	 */
 	private DropTargetContext getContext() {
 		return context;
 	}

 	/**
 	 * Returns the set of registered transfer agents. This is determined from
 	 * the drop target service.
 	 *
 	 * @return Transfer[] an array of transfer agents
 	 */
 	public Transfer[] getAllTransferAgents() {
 		/* Return null if no registered agents */
 		if (getAdapters() == null || getAdapters().length == 0) {
 			return null;
 		}

 		/* Get the transfers */
 		ArrayList list = new ArrayList();
 		for (int i = 0; i < getAdapters().length; i++) {
 			list.add(getAdapters()[i].getTransferAgent().getTransfer());
 		}

 		return (Transfer[]) list.toArray(new Transfer[list.size()]);
 	}

 	/**
 	 * Returns the set of transfer drop target adapters. The adapters are
 	 * created based on the provided transfer ids determined from the drag and
 	 * drop service.
 	 *
 	 * @return ITransferDropTargetListener[] an array of transfer adapters
 	 */
 	private ITransferDropTargetListener[] getAllTransferAdapters() {
 		/* Create placeholder for possible adapters */
 		ArrayList listOfSupportedAdapters = new ArrayList();

 		/* Get the ids from the drag and drop service */
 		String[] transferIds = DragDropListenerService.getInstance()
 			.getAllTransferIds(getContext().getActivePart().getSite().getId(),
 				IListenerContext.DROP);

 		/* Iterate through the ids */
 		if (transferIds == null || transferIds.length == 0) {
 			return null;
 		}

 		/* Create the adapters */
 		for (int i = 0; i < transferIds.length; i++) {
 			ITransferDropTargetListener adapter = TransferAdapterService
 				.getInstance().getTransferDropTargetAdapter(transferIds[i]);

 			if (adapter != null) {
 				listOfSupportedAdapters.add(adapter);
 			}
 		}

 		/* Return the adapters */
 		return !listOfSupportedAdapters.isEmpty() ? (ITransferDropTargetListener[]) listOfSupportedAdapters
 			.toArray(new ITransferDropTargetListener[listOfSupportedAdapters
 				.size()])
 			: null;
 	}

 	/**
 	 * Set the chosen adapter.
 	 *
 	 * @param event
 	 *            the event
 	 */
 	private void setChosenAdapter(DropTargetEvent event) {
 		/* Set the chosen adapter to null */
 		chosenAdapter = null;

 		/* Get the data types */
 		TransferData[] dataTypes = event.dataTypes;
 		if (dataTypes == null || dataTypes.length == 0) {
 			if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
 				CommonUIServicesDNDDebugOptions.DND)) {
 				Trace
 					.trace(CommonUIServicesDNDPlugin.getDefault(),
 						CommonUIServicesDNDDebugOptions.DND,
 						"setChosenAdapter::No transfer types available in the event"); //$NON-NLS-1$
 			}

 			return;
 		}

 		/* Check if there are any adapters */
 		if (getAdapters() == null) {
 			if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
 				CommonUIServicesDNDDebugOptions.DND)) {
 				Trace
 					.trace(CommonUIServicesDNDPlugin.getDefault(),
 						CommonUIServicesDNDDebugOptions.DND,
 						"setChosenAdapter::No adapters registered with this target"); //$NON-NLS-1$
 			}
 			return;
 		}

 		/* Check if the target is null */
 		if (getContext().getCurrentTarget() == null) {
 			if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
 				CommonUIServicesDNDDebugOptions.DND)) {
 				Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
 					CommonUIServicesDNDDebugOptions.DND,
 					"setChosenAdapter::Current target is null"); //$NON-NLS-1$
 			}

 			return;
 		}

 		/*
 		 * Preferably use the selection transfer for in-process drag and drop
 		 * operations. Iterate through the adapters
 		 */
 		for (int i = 0; i < getAdapters().length; i++) {
 			if (getAdapters()[i].getTransferAgent().isSelectionType()) {
 				/* Check if the adapter can handle */
 				if (getAdapters()[i].canSupport(event)) {
 					/* Set the adapter */
 					chosenAdapter = getAdapters()[i];
 					return;
 				}
 			}
 		}

 		/* Iterate through the rest of the adapters */
 		for (int i = 0; i < getAdapters().length; i++) {
 			if (!getAdapters()[i].getTransferAgent().isSelectionType()) {
 				/* Check if the adapter can handle */
 				if (getAdapters()[i].canSupport(event)) {
 					/* Set the adapter */
 					chosenAdapter = getAdapters()[i];
 					return;
 				}
 			}
 		}
 	}

 	/**
 	 * Returns the chosenAdapter.
 	 *
 	 * @return ITransferDropTargetListener
 	 */
 	private ITransferDropTargetListener getChosenAdapter() {
 		return chosenAdapter;
 	}

 	/**
 	 * Handles the specified exception.
 	 *
 	 * @param exception
 	 *            The exception to be handled.
 	 * @param displayDialog
 	 *            boolean to indicate whether to display dialog
 	 */
 	private void handle(Throwable exception, boolean displayDialog) {
 		if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
 			CommonUIServicesDNDDebugOptions.EXCEPTIONS_CATCHING)) {
 			Trace.catching(CommonUIServicesDNDPlugin.getDefault(),
 				CommonUIServicesDNDDebugOptions.EXCEPTIONS_CATCHING,
 				getClass(), "handle", exception); //$NON-NLS-1$
 		}

 		IStatus status = new Status(IStatus.ERROR, CommonUIServicesDNDPlugin
 			.getPluginId(), CommonUIServicesDNDStatusCodes.DROP_ACTION_FAILURE,
 			CommonUIServicesDNDMessages.DelegatingDropTargetAdapter__ERROR__errorMessage, exception);

 		Log.log(CommonUIServicesDNDPlugin.getDefault(), status);

 		if (displayDialog) {

 			status = new Status(IStatus.ERROR, CommonUIServicesDNDPlugin
 				.getPluginId(),
 				CommonUIServicesDNDStatusCodes.DROP_ACTION_FAILURE,
 				CommonUIServicesDNDMessages.DelegatingDropTargetAdapter_errorMessage,
 				exception);

 			ErrorDialog.openError(getContext().getActivePart().getSite()
 				.getShell(), null, null, status);
 		}
 	}

 	/**
 	 * Return the original drop type
 	 *
 	 * @return int the drop type
 	 */
 	private int getOrigDropType() {
 		return origDropType;
 	}

 	/**
 	 * Set the original drop type
 	 *
 	 * @param anOrigDropType
 	 *            the drop type
 	 */
 	private void setOrigDropType(int anOrigDropType) {
 		this.origDropType = anOrigDropType;
 	}

 	/**
 	 * Return the current drop type
 	 *
 	 * @return int the drop type
 	 */
 	private int getCurrentDropType() {
 		return currentDropType;
 	}

 	/**
 	 * Set the current drop type
 	 *
 	 * @param aCurrentDropType
 	 *            the drop type
 	 */
 	private void setCurrentDropType(int aCurrentDropType) {
 		this.currentDropType = aCurrentDropType;
 	}

 	/**
 	 * Inititializes the transfer adapters' context
 	 */
 	private void initAdapters() {
 		/* Iterate through the adapters */

 		if (getAdapters() != null)
 			for (int i = 0; i < getAdapters().length; i++) {

 				/* Initialize the adapter */
 				getAdapters()[i].init(getContext());

 			}

 	}
 }
	/******************************************************************************
	* Copyright (c) 2002, 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 org.eclipse.gmf.runtime.common.ui.services.dnd.drop;

	import java.util.ArrayList;

	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.jface.dialogs.ErrorDialog;
	import org.eclipse.swt.dnd.DND;
	import org.eclipse.swt.dnd.DropTargetEvent;
	import org.eclipse.swt.dnd.DropTargetListener;
	import org.eclipse.swt.dnd.Transfer;
	import org.eclipse.swt.dnd.TransferData;

	import org.eclipse.gmf.runtime.common.core.util.Log;
	import org.eclipse.gmf.runtime.common.core.util.Trace;
	import org.eclipse.gmf.runtime.common.ui.services.dnd.core.DragDropListenerService;
	import org.eclipse.gmf.runtime.common.ui.services.dnd.core.IListenerContext;
	import org.eclipse.gmf.runtime.common.ui.services.dnd.core.TransferAdapterService;
	import org.eclipse.gmf.runtime.common.ui.services.dnd.internal.CommonUIServicesDNDDebugOptions;
	import org.eclipse.gmf.runtime.common.ui.services.dnd.internal.CommonUIServicesDNDPlugin;
	import org.eclipse.gmf.runtime.common.ui.services.dnd.internal.CommonUIServicesDNDStatusCodes;
	import org.eclipse.gmf.runtime.common.ui.services.dnd.internal.l10n.CommonUIServicesDNDMessages;

	/**
	* This class delegates all the drop target events to the transfer drop target
	* adapter. The transfer adapter delegates to the registered listeners
	*
	* @author Vishy Ramaswamy
	*/
	public class DelegatingDropTargetAdapter
	implements DropTargetListener {

	/**
	* Attribute for the error message
	*/
	//private static final String ERROR_MSG = ResourceManager
	// .getI18NString("DelegatingDropTargetAdapter.errorMessage"); //$NON-NLS-1$

	/**
	* Attribute for the error message for logging
	*/
	//private static final String ERROR_MSG_LOG = ResourceManager
	// .getI18NString("DelegatingDropTargetAdapter._ERROR_.errorMessage"); //$NON-NLS-1$

	/**
	* Attribute for the transfer drop target adapters.
	*/
	private ITransferDropTargetListener[] adapters = null;

	/**
	* Attribute for the current transfer drop target adapter.
	*/
	private ITransferDropTargetListener chosenAdapter = null;

	/**
	* Attribute for the drop target context.
	*/
	private final DropTargetContext context;

	/**
	* Attribute for the original drop event type.
	*/
	private int origDropType = DND.DROP_NONE;

	/**
	* Attribute for the current drop event type.
	*/
	private int currentDropType = DND.DROP_NONE;

	/**
	* Constructor for DelegatingDropTargetAdapter.
	*
	* @param aContext
	* context information for the drop target
	*/
	public DelegatingDropTargetAdapter(DropTargetContext aContext) {
	super();

	assert null != aContext : "context information for the drop target cannot be null"; //$NON-NLS-1$
	this.context = aContext;

	/* Set the adapters */
	adapters = getAllTransferAdapters();
	}

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.swt.dnd.DropTargetListener#dragEnter(org.eclipse.swt.dnd.DropTargetEvent)
	*/
	public void dragEnter(DropTargetEvent event) {
	try {
	/* Set the original drop type */
	setOrigDropType(event.detail);

	/* Set the current target and location */
	getContext().setCurrentTargetAndLocation(event);

	/*
	* Re-Initialize the Transfer Adapters with dynamically with the
	* correct context
	*/
	initAdapters();

	/* Set the chosen adapter */
	setChosenAdapter(event);

	/* Check if a chosen adapter exists */
	if (getChosenAdapter() != null) {
	getChosenAdapter().dragEnter(event);
	} else {
	/* Delegate to the drop target */
	getContext().dragEnter(event);
	}

	if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND)) {
	String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
	.getClass().getName()
	: "No Adapter"; //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"DragEnter::Event detail is " + event.detail); //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"DragEnter::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
	}
	} catch (Throwable e) {
	event.detail = DND.DROP_NONE;
	handle(e, false);
	}
	}

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.swt.dnd.DropTargetListener#dragLeave(org.eclipse.swt.dnd.DropTargetEvent)
	*/
	public void dragLeave(DropTargetEvent event) {
	try {
	/* Check if a chosen adapter exists */
	if (getChosenAdapter() != null) {
	getChosenAdapter().dragLeave(event);
	} else {
	/* Delegate to the drop target */
	getContext().dragLeave(event);
	}

	if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND)) {
	String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
	.getClass().getName()
	: "No Adapter"; //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"DragLeave::Event detail is " + event.detail); //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"DragLeave::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
	}
	} catch (Throwable e) {
	handle(e, false);
	}
	}

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.swt.dnd.DropTargetListener#dragOperationChanged(org.eclipse.swt.dnd.DropTargetEvent)
	*/
	public void dragOperationChanged(DropTargetEvent event) {
	try {
	/* Set the original drop type */
	setOrigDropType(event.detail);

	/* Set the current target and location */
	getContext().setCurrentTargetAndLocation(event);

	/* Set the chosen adapter */
	setChosenAdapter(event);

	/* Check if a chosen adapter exists */
	if (getChosenAdapter() != null) {
	getChosenAdapter().dragOperationChanged(event);
	} else {
	/* Delegate to the drop target */
	getContext().dragOperationChanged(event);
	}

	if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND)) {
	String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
	.getClass().getName()
	: "No Adapter"; //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"DragOperationChanged::Event detail is " + event.detail); //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"DragOperationChanged::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
	}
	} catch (Throwable e) {
	event.detail = DND.DROP_NONE;
	handle(e, false);
	}
	}

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.swt.dnd.DropTargetListener#dragOver(org.eclipse.swt.dnd.DropTargetEvent)
	*/
	public void dragOver(DropTargetEvent event) {
	try {
	/* Set the current target and location */
	getContext().setCurrentTargetAndLocation(event);

	/* Set the event detail as the original drop type */
	event.detail = getOrigDropType();

	/* Set the chosen adapter */
	setChosenAdapter(event);

	/* Check if a chosen adapter exists */
	if (getChosenAdapter() != null) {
	getChosenAdapter().dragOver(event);

	/* Check the event detail */
	if (event.detail != DND.DROP_NONE) {
	setCurrentDropType(event.detail);
	}
	} else {
	/* Delegate to the drop target */
	getContext().dragOver(event);
	}

	if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND)) {
	String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
	.getClass().getName()
	: "No Adapter"; //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"DragOver::Event detail is " + event.detail); //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"DragOver::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
	}
	} catch (Throwable e) {
	event.detail = DND.DROP_NONE;
	handle(e, false);
	}
	}

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.swt.dnd.DropTargetListener#drop(org.eclipse.swt.dnd.DropTargetEvent)
	*/
	public void drop(DropTargetEvent event) {
	try {
	/*
	* Save the event detail just in case the event has to be delegated
	* to the drop target
	*/
	int oldDetail = event.detail;

	/* Set the current target and location */
	getContext().setCurrentTargetAndLocation(event);

	/* Set the event detail as the current drop type */
	event.detail = getCurrentDropType();

	/* Set the chosen adapter */
	setChosenAdapter(event);

	/* Check if a chosen adapter exists */
	if (getChosenAdapter() != null) {
	getChosenAdapter().drop(event);
	} else {
	event.detail = oldDetail;

	/* Delegate to the drop target */
	getContext().drop(event);
	}

	if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND)) {
	String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
	.getClass().getName()
	: "No Adapter"; //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"Drop::Event detail is " + event.detail); //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"Drop::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
	}
	} catch (Throwable e) {
	event.detail = DND.DROP_NONE;
	handle(e, true);
	}
	}

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.swt.dnd.DropTargetListener#dropAccept(org.eclipse.swt.dnd.DropTargetEvent)
	*/
	public void dropAccept(DropTargetEvent event) {
	try {
	/*
	* Save the event detail just in case the event has to be delegated
	* to the drop target
	*/
	int oldDetail = event.detail;

	/* Set the current target and location */
	getContext().setCurrentTargetAndLocation(event);

	/* Set the event detail as the original drop type */
	event.detail = getCurrentDropType();

	/* Set the chosen adapter */
	setChosenAdapter(event);

	/* Check if a chosen adapter exists */
	if (getChosenAdapter() != null) {
	getChosenAdapter().dropAccept(event);

	/* Check the event detail */
	if (event.detail != getCurrentDropType()) {
	setCurrentDropType(event.detail);
	}
	} else {
	event.detail = oldDetail;

	/* Delegate to the drop target */
	getContext().dropAccept(event);
	}

	if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND)) {
	String adapterChosen = getChosenAdapter() != null ? getChosenAdapter()
	.getClass().getName()
	: "No Adapter"; //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"DropAccept::Event detail is " + event.detail); //$NON-NLS-1$
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"DropAccept::Chosen adapter is " + adapterChosen); //$NON-NLS-1$
	}
	} catch (Throwable e) {
	event.detail = DND.DROP_NONE;
	handle(e, false);
	}
	}

	/**
	* Returns the adapters.
	*
	* @return ITransferDropTargetListener[]
	*/
	private ITransferDropTargetListener[] getAdapters() {
	return adapters;
	}

	/**
	* Returns the drop target context.
	*
	* @return DropTargetContext
	*/
	private DropTargetContext getContext() {
	return context;
	}

	/**
	* Returns the set of registered transfer agents. This is determined from
	* the drop target service.
	*
	* @return Transfer[] an array of transfer agents
	*/
	public Transfer[] getAllTransferAgents() {
	/* Return null if no registered agents */
	if (getAdapters() == null \|\| getAdapters().length == 0) {
	return null;
	}

	/* Get the transfers */
	ArrayList list = new ArrayList();
	for (int i = 0; i < getAdapters().length; i++) {
	list.add(getAdapters()[i].getTransferAgent().getTransfer());
	}

	return (Transfer[]) list.toArray(new Transfer[list.size()]);
	}

	/**
	* Returns the set of transfer drop target adapters. The adapters are
	* created based on the provided transfer ids determined from the drag and
	* drop service.
	*
	* @return ITransferDropTargetListener[] an array of transfer adapters
	*/
	private ITransferDropTargetListener[] getAllTransferAdapters() {
	/* Create placeholder for possible adapters */
	ArrayList listOfSupportedAdapters = new ArrayList();

	/* Get the ids from the drag and drop service */
	String[] transferIds = DragDropListenerService.getInstance()
	.getAllTransferIds(getContext().getActivePart().getSite().getId(),
	IListenerContext.DROP);

	/* Iterate through the ids */
	if (transferIds == null \|\| transferIds.length == 0) {
	return null;
	}

	/* Create the adapters */
	for (int i = 0; i < transferIds.length; i++) {
	ITransferDropTargetListener adapter = TransferAdapterService
	.getInstance().getTransferDropTargetAdapter(transferIds[i]);

	if (adapter != null) {
	listOfSupportedAdapters.add(adapter);
	}
	}

	/* Return the adapters */
	return !listOfSupportedAdapters.isEmpty() ? (ITransferDropTargetListener[]) listOfSupportedAdapters
	.toArray(new ITransferDropTargetListener[listOfSupportedAdapters
	.size()])
	: null;
	}

	/**
	* Set the chosen adapter.
	*
	* @param event
	* the event
	*/
	private void setChosenAdapter(DropTargetEvent event) {
	/* Set the chosen adapter to null */
	chosenAdapter = null;

	/* Get the data types */
	TransferData[] dataTypes = event.dataTypes;
	if (dataTypes == null \|\| dataTypes.length == 0) {
	if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND)) {
	Trace
	.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"setChosenAdapter::No transfer types available in the event"); //$NON-NLS-1$
	}

	return;
	}

	/* Check if there are any adapters */
	if (getAdapters() == null) {
	if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND)) {
	Trace
	.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"setChosenAdapter::No adapters registered with this target"); //$NON-NLS-1$
	}
	return;
	}

	/* Check if the target is null */
	if (getContext().getCurrentTarget() == null) {
	if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND)) {
	Trace.trace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.DND,
	"setChosenAdapter::Current target is null"); //$NON-NLS-1$
	}

	return;
	}

	/*
	* Preferably use the selection transfer for in-process drag and drop
	* operations. Iterate through the adapters
	*/
	for (int i = 0; i < getAdapters().length; i++) {
	if (getAdapters()[i].getTransferAgent().isSelectionType()) {
	/* Check if the adapter can handle */
	if (getAdapters()[i].canSupport(event)) {
	/* Set the adapter */
	chosenAdapter = getAdapters()[i];
	return;
	}
	}
	}

	/* Iterate through the rest of the adapters */
	for (int i = 0; i < getAdapters().length; i++) {
	if (!getAdapters()[i].getTransferAgent().isSelectionType()) {
	/* Check if the adapter can handle */
	if (getAdapters()[i].canSupport(event)) {
	/* Set the adapter */
	chosenAdapter = getAdapters()[i];
	return;
	}
	}
	}
	}

	/**
	* Returns the chosenAdapter.
	*
	* @return ITransferDropTargetListener
	*/
	private ITransferDropTargetListener getChosenAdapter() {
	return chosenAdapter;
	}

	/**
	* Handles the specified exception.
	*
	* @param exception
	* The exception to be handled.
	* @param displayDialog
	* boolean to indicate whether to display dialog
	*/
	private void handle(Throwable exception, boolean displayDialog) {
	if (Trace.shouldTrace(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.EXCEPTIONS_CATCHING)) {
	Trace.catching(CommonUIServicesDNDPlugin.getDefault(),
	CommonUIServicesDNDDebugOptions.EXCEPTIONS_CATCHING,
	getClass(), "handle", exception); //$NON-NLS-1$
	}

	IStatus status = new Status(IStatus.ERROR, CommonUIServicesDNDPlugin
	.getPluginId(), CommonUIServicesDNDStatusCodes.DROP_ACTION_FAILURE,
	CommonUIServicesDNDMessages.DelegatingDropTargetAdapter__ERROR__errorMessage, exception);

	Log.log(CommonUIServicesDNDPlugin.getDefault(), status);

	if (displayDialog) {

	status = new Status(IStatus.ERROR, CommonUIServicesDNDPlugin
	.getPluginId(),
	CommonUIServicesDNDStatusCodes.DROP_ACTION_FAILURE,
	CommonUIServicesDNDMessages.DelegatingDropTargetAdapter_errorMessage,
	exception);

	ErrorDialog.openError(getContext().getActivePart().getSite()
	.getShell(), null, null, status);
	}
	}

	/**
	* Return the original drop type
	*
	* @return int the drop type
	*/
	private int getOrigDropType() {
	return origDropType;
	}

	/**
	* Set the original drop type
	*
	* @param anOrigDropType
	* the drop type
	*/
	private void setOrigDropType(int anOrigDropType) {
	this.origDropType = anOrigDropType;
	}

	/**
	* Return the current drop type
	*
	* @return int the drop type
	*/
	private int getCurrentDropType() {
	return currentDropType;
	}

	/**
	* Set the current drop type
	*
	* @param aCurrentDropType
	* the drop type
	*/
	private void setCurrentDropType(int aCurrentDropType) {
	this.currentDropType = aCurrentDropType;
	}

	/**
	* Inititializes the transfer adapters' context
	*/
	private void initAdapters() {
	/* Iterate through the adapters */

	if (getAdapters() != null)
	for (int i = 0; i < getAdapters().length; i++) {

	/* Initialize the adapter */
	getAdapters()[i].init(getContext());

	}

	}
	}