Bug 155178 [Deploy] Preview report failed on war deployed weblogic server
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/service/ReportEngineService.java
/**
	 * Get engine instance.
	 * 
	 * @return the single report engine service
	 */
	public static ReportEngineService getInstance( )
	{
		return instance;
	}
	/**
	 * Get engine instance.
	 * 
	 * @param servletConfig
	 * @throws BirtException
	 * 
	 */
	public synchronized static void initEngineInstance(
			ServletConfig servletConfig ) throws BirtException
	{
		if ( ReportEngineService.instance != null )
		{
			return;
		}
		ReportEngineService.instance = new ReportEngineService( servletConfig );
	}
	/**
	 * Get all the files under the specified folder (including all the files
	 * under sub-folders)
	 * 
	 * @param dir -