Bug 191637 Empty cube causes error
Comment removed as requested by the submitter - 2007-06-08 droy
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/olap/data/impl/dimension/Hierarchy.java
}
	/**
	 * 
	 * @throws IOException
	 */
	private void openReadDocuemntObject( ) throws IOException
	{
		if(documentObj==null)
			documentObj = documentManager.openDocumentObject( NamingUtil.getHierarchyDocName( dimensionName, name ) );
		if(offsetDocObj==null)
			offsetDocObj = documentManager.openDocumentObject( NamingUtil.getHierarchyOffsetDocName( dimensionName, name ) );
	}
	
	/**
	 * 
	 * @throws IOException
	 * @throws DataException
	 */
	public void loadFromDisk( ) throws IOException, DataException
	{
		openReadDocuemntObject( );
		int size = documentObj.readInt( );
		levels = new Level[documentObj.readInt( )];
		for ( int i = 0; i < levels.length; i++ )
		{
			String levelName = documentObj.readString( );
			String[] keyColName = new String[documentObj.readInt( )];
			int[] keyDataType = new int[keyColName.length];
			for ( int j = 0; j < keyColName.length; j++ )
			{