Bug 188252 [enhancement] remove cube cache when server is shutdown
steps to reproduce: - create a report design using cube and xtab - deploy it to tomcat BIRT viewer - preview it note that one folder named temp29330913 was created under tomcat home folder, there are three files (Customer Cubedata, Customer CubeOat, Customer Cubeobj) within this folder. these won't be removed even after tomcat is shutdown. is it appropriate if these are some kind of cache for the cube data?
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/olap/data/document/FileDocumentManager.java
{
	
	private BufferedRandomAccessFile objectFile = null;
	private BufferedRandomAccessFile OatFile = null;
	private BufferedRandomAccessFile dataFile = null;
	private HashMap documentObjectMap = null;
	
	/**
	 * 
	 * @param dirName
	 * @param managerName
	 * @return
	 * @throws DataException
	 * @throws IOException
	 */
	static FileDocumentManager createManager( String dirName, String managerName ) throws DataException, IOException
	{
		FileDocumentManager manager = new FileDocumentManager( );
		manager.create( dirName, managerName );
		return manager;
	}
	
	/**
	 * 
	 * @param dirName
	 * @param managerName
	 * @return
	 * @throws DataException