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/util/DiskIndex.java
offsetDocumentObject.seek( ( keyCount - n ) * 4 );
		documentObject.seek( offsetDocumentObject.readInt( ) );
		for ( int i = 0; i < n; i++ )
		{
			resultList.add( readKeyObject( ) );
		}
		return resultList;
	}
	
	/**
	 * 
	 * @param percent
	 * @return
	 * @throws IOException
	 */
	public IDiskArray topPercent( double percent ) throws IOException
	{
		return topN( (int)(keyCount * percent) );
	}
	
	/**
	 * 
	 * @param n
	 * @return
	 * @throws IOException
	 */
	public IDiskArray bottomN( int n ) throws IOException
	{
		BufferedStructureArray resultList = new BufferedStructureArray( IndexKey.getCreator( ),
				Math.min( n, Constants.MAX_LIST_BUFFER_SIZE ) );