Bug 164764 Joint data set does not work properly using attached flatfile
The data set preview keep empty in joint data set. Step to reproduce: 1.Create two data sets based on attached flat file 2.Make an inner join using joint data set with key "A". 3.Preview data set in data set editor. Expect result: The data set preview correctly Actual result: The data set preview is empty.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/script/ScriptEvalUtil.java
}	
	
	/**
	 * Utility for miscellaneous use
	 * 
	 */
	private static class MiscUtil
	{
		/**
		 * 
		 * @param resultExpr
		 * @param resultOp1
		 * @return
		 */
		private static boolean isSameType( Object resultExpr, Object resultOp1 )
		{
			return resultExpr.getClass( ).equals( resultOp1.getClass( ) );
		}
		
		/**
		 * 
		 * @param result
		 * @return
		 */
		private static boolean isNumericOrString( Object result )
		{
			return ( result instanceof Number ) || ( result instanceof String );
		}
		/**
		 *