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 void setTarget( DesignElement target )
	{
		this.target = target;
	}
	/**
	 * Returns the event type. The following event types are defined:
	 * <ul>
	 * <li>CONTENT_EVENT</li>
	 * <li>ELEMENT_DELETE_EVENT</li>
	 * <li>EXTENDS_EVENT</li>
	 * <li>NAME_EVENT</li>
	 * <li>NAME_SPACE_EVENT</li>
	 * <li>PROPERTY_EVENT</li>
	 * <li>STYLE_EVENT</li>
	 * <li>USER_PROP_EVENT</li>
	 * <li>CUSTOM_MSG_EVENT</li>
	 * <li>EXTENSION_PROPERTY_DEFINITION_EVENT</li>
	 * <li>NOTIFICATION_EVENT</li>
	 * <li>VALIDATION_EVENT</li>
	 * <li>LIBRARY_EVENT</li>
	 * <li>ATTRIBUTE_EVENT</li>
	 * <li>DISPOSE_EVENT</li>
	 * <li>CONTENT_REPLACE_EVENT</li>
	 * <li>TEMPLATE_TRANSFORM_EVENT</li>
	 * </ul>
	 * 
	 * @return the event type.
	 */
	public abstract int getEventType( );
}