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package org.eclipse.swt.dnd;
/*
* Licensed Materials - Property of IBM,
* WebSphere Studio Workbench
* (c) Copyright IBM Corp 2000
*/
import org.eclipse.swt.graphics.*;
import java.util.EventListener;
/**
* The <code>DropTargetListener</code> class provides event notification to the application for DropTarget events.
*
* <p>As the user moves the cursor into, over and out of a Control that has been designated as a DropTarget, events
* indicate what operation can be performed and what data can be transferred if a drop where to occur at that point.
* The application can respond to these events and change the type of data that will be dropped, change the operation
* that will be performed or stop any drop from happening on the current target.</p>
*
* <p>When the user causes a drop to happen by releasing the mouse over a valid drop target, the application has one
* last chance to change the data type of the drop through the DropAccept event. If the drop is still allowed, the
* DropAccept event is immediately followed by the Drop event. In the Drop event, the application can still change the
* operation that is performed but the data type is fixed.</p>
*
*/
public interface DropTargetListener extends EventListener {
/**
* The cursor has entered the drop target boundaries.
*
* <p>The following fields in the DropTargetEvent apply:
* <ul>
* <li>(in)widget - the DragSource object that initiated the drag
* <li>(in)time - the time the drop occurred
* <li>(in)x - the x-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in)y - the y-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in)dataTypes - a list of the types of data that the <code>DragSource</code> can support
* <li>(in,out)currentDataType - the specific type of data that will be provided
* <li>(in)operations - a list of the operations that the DragSource can support (e.g. <code>DND.DROP_MOVE | DND.DROP_COPY | DND.DROP_LINK</code>)
* <li>(in,out)detail - the operation being performed (one of DND.DROP_MOVE, DND.DROP_COPY, DND.DROP_LINK, DND.DROP_NONE)
* </ul></p>
*
* <p>The application can change the operation that will be performed by modifying the <code>detail</code> field
* but the choice must be one of the values in the <code>operations</code> field.
* The application can also change the type of data being requested by modifying the <code>currentDataTypes</code>
* field but the value must be one of the values in the <code>dataTypes</code> list.</p>
*
* @param event the information associated with the drag enter event
*
*/
public void dragEnter(DropTargetEvent event);
/**
* The cursor has left the drop target boundaries.
*
* <p>The following fields in the DropTargetEvent apply:
* <ul>
* <li>(in)widget - the DragSource object that initiated the drag
* <li>(in)time - the time the drop occurred
* <li>(in)x - the x-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in)y - the y-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in)dataTypes - a list of the types of data that the <code>DragSource</code> can support
* <li>(in,out)currentDataType - the specific type of data that will be provided
* <li>(in)operations - a list of the operations that the DragSource can support (e.g. <code>DND.DROP_MOVE | DND.DROP_COPY | DND.DROP_LINK</code>)
* <li>(in,out)detail - the operation being performed (one of DND.DROP_MOVE, DND.DROP_COPY, DND.DROP_LINK, DND.DROP_NONE)
* </ul></p>
*
* <p>The application can change the operation that will be performed by modifying the <code>detail</code> field
* but the choice must be one of the values in the <code>operations</code> field.
* The application can also change the type of data being requested by modifying the <code>currentDataTypes</code>
* field but the value must be one of the values in the <code>dataTypes</code> list.</p>
*
* @param event the information associated with the drag leave event
*
*/
public void dragLeave(DropTargetEvent event);
/**
* The operation being performed has changed (usually due to the user changing the selected key while dragging).
*
* <p>The following fields in the DropTargetEvent apply:
* <ul>
* <li>(in)widget - the DragSource object that initiated the drag
* <li>(in)time - the time the drop occurred
* <li>(in)x - the x-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in)y - the y-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in)dataTypes - a list of the types of data that the <code>DragSource</code> can support
* <li>(in,out)currentDataType - the specific type of data that will be provided
* <li>(in)operations - a list of the operations that the DragSource can support (e.g. <code>DND.DROP_MOVE | DND.DROP_COPY | DND.DROP_LINK</code>)
* <li>(in,out)detail - the operation being performed (one of DND.DROP_MOVE, DND.DROP_COPY, DND.DROP_LINK, DND.DROP_NONE)
* </ul></p>
*
* <p>The application can change the operation that will be performed by modifying the <code>detail</code> field
* but the choice must be one of the values in the <code>operations</code> field.
* The application can also change the type of data being requested by modifying the <code>currentDataTypes</code>
* field but the value must be one of the values in the <code>dataTypes</code> list.</p>
*
* @param event the information associated with the drag operation changed event
*/
public void dragOperationChanged(DropTargetEvent event);
/**
* The cursor is moving over the drop target.
*
* <p>The following fields in the DropTargetEvent apply:
* <ul>
* <li>(in)widget - the DragSource object that initiated the drag
* <li>(in)time - the time the drop occurred
* <li>(in)x - the x-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in)y - the y-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in)dataTypes - a list of the types of data that the <code>DragSource</code> can support
* <li>(in,out)currentDataType - the specific type of data that will be provided
* <li>(in)operations - a list of the operations that the DragSource can support (e.g. <code>DND.DROP_MOVE | DND.DROP_COPY | DND.DROP_LINK</code>)
* <li>(in,out)detail - the operation being performed (one of DND.DROP_MOVE, DND.DROP_COPY, DND.DROP_LINK, DND.DROP_NONE)
* </ul></p>
*
* <p>The application can change the operation that will be performed by modifying the <code>detail</code> field
* but the choice must be one of the values in the <code>operations</code> field.
* The application can also change the type of data being requested by modifying the <code>currentDataTypes</code>
* field but the value must be one of the values in the <code>dataTypes</code> list.</p>
*
* @param event the information associated with the drag over event
*
*/
public void dragOver(DropTargetEvent event);
/**
* The data is being dropped.
*
* <p>The following fields in DropTargetEvent apply:
* <ul>
* <li>(in)widget - the DragSource object that initiated the drag
* <li>(in)time - the time the drop occurred
* <li>(in)x - the x-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in)y - the y-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in,out)detail - the operation being performed (one of DND.DROP_MOVE, DND.DROP_COPY, DND.DROP_LINK, DND.DROP_NONE)
* <li>(in)currentDataType - the specific type of data that will be provided
* <li>(in)data - the data (which is of type currentDataType)
* </ul></p>
*
* <p>The application can refuse to perform the drop operation by setting the detail field to DND.DROP_NONE.</p>
*
* @param event the information associated with the drop event
*
*/
public void drop(DropTargetEvent event);
/**
* The drop target is given the chance to change the nature of the drop. It can veto the drop by setting the
* <code>event.detail</code> field to <code>DND.DROP_NONE</code>, it can change the data of data that will be
* dropped by setting the <code>event.currentDataType</code> field to a different value or it can change the
* operation that will be performed by changing the <code>event.detail</code> field.
*
* <p>The following fields in the DropTargetEvent apply:
* <ul>
* <li>(in)widget - the DragSource object that initiated the drag
* <li>(in)time - the time the drop occurred
* <li>(in)x - the x-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in)y - the y-cordinate of the cursor relative to the <code>DropTarget Control</code>
* <li>(in)dataTypes - a list of the types of data that the <code>DragSource</code> can support
* <li>(in,out)currentDataType - the specific type of data that will be provided
* <li>(in)operations - a list of the operations that the DragSource can support (e.g. <code>DND.DROP_MOVE | DND.DROP_COPY | DND.DROP_LINK</code>)
* <li>(in,out)detail - the operation being performed (one of DND.DROP_MOVE, DND.DROP_COPY, DND.DROP_LINK, DND.DROP_NONE)
* </ul></p>
*
* <p>The application can change the operation that will be performed by modifying the <code>detail</code> field
* but the choice must be one of the values in the <code>operations</code> field.
* The application can also change the type of data being requested by modifying the <code>currentDataTypes</code>
* field but the value must be one of the values in the <code>dataTypes</code> list.</p>
*
* @param event the information associated with the drop accept event
*
*/
public void dropAccept(DropTargetEvent event);
}
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