Bug 201019 [Automation][Regression]Exception is thrown when running reportdesign
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/adapter/ExpressionUtil.java
{
	private static final String TOTAL_PREFIX = "TOTAL_COLUMN_";
	private int totalColumnSuffix = 0;
	public ITotalExprBindings prepareTotalExpressions( List exprs ) throws EngineException
	{
		return prepareTotalExpressions( exprs, null );
	}
	/**
	 * 
	 * @param exprs
	 * @return
	 * @throws EngineException 
	 */
	public ITotalExprBindings prepareTotalExpressions( List exprs, String groupName ) throws EngineException
	{
		
		TotalExprBinding result = new TotalExprBinding();
		List l = new ArrayList( );
		for ( int i = 0; i < exprs.size( ); i++ )
		{
			
			Object key = exprs.get( i );
			result.addColumnBindings( l );
			if ( key instanceof String )
			{
				String expr = key == null ? null : key.toString( );
				String newExpr = prepareTotalExpression( expr, l, groupName );
				result.addColumnBindings( l );