Bug 150347 Support binary stream as preview image.
See 144843. We need model to save binary strame as report preview image. Currently, preview image is an external image. Maybe need a type to distinguish preview image type.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/activity/NotificationEvent.java
*/
	public Object getSender( )
	{
		return sender;
	}
	/**
	 * Sets the sender based on the information provided to the command.
	 * 
	 * @param sender
	 *            the sender to set.
	 */
	public void setSender( Object sender )
	{
		this.sender = sender;
	}
	/**
	 * Returns the target element: the part of the design that actually changed.
	 * 
	 * @return the target.
	 */
	public DesignElement getTarget( )
	{
		return target;
	}
	/**
	 * Sets the target element.
	 * 
	 * @param target
	 *            the target element to set.
	 */