Bug 133780 Execution sequence of valueExpr(DataItem) and onCreate() is not correct.
In the attached design. There is a DataItem in the table footer that I used to do a sum of the "Amount" column. In the test, I write the onCreate() method as: params["amount"]=Total.sum(row["AMOUNT"]); It passes the aggregation value to a parameter. In the "valueExpr" I write as: "AMOUNT:" + params["amount"] The expression is expected to export the sum. Actual output is: AMOUNT:null Followings are the definitions from Rom Text Spec & Rom Scripting Spec, valueExpr usually should be evalated after the onCreate() method. DataItem.valueExpr: The expression is usually evaluated when the report is rendered, not in the Factory, though it may be evaluated in the Factory also. onCreate: Executed when the element is created in the Factory. Called after the item is created, but before the item is saved to the report document file.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/DataItemExecutor.java
}
	/**
	 * construct a data item executor by giving execution context and report
	 * executor visitor
	 * 
	 * @param context
	 *            the executor context
	 * @param itemEmitter
	 *            the emitter
	 */
	public DataItemExecutor( ExecutionContext context,
			IReportItemVisitor visitor )
	{
		super( context, visitor );
	}
	/**
	 * execute the data item.
	 * 
	 * <li> create the data content object
	 * <li> push it to the stack
	 * <li> open the data set, seek to the first record
	 * <li> intialize the content object
	 * <li> process the style, visiblitly, action and bookmark
	 * <li> evaluate the expression, and map it to a predefined value.
	 * <li> call the onCreate if necessary
	 * <li> pass it to emitter
	 * <li> close the data set if any
	 * <li> pop the stack.
	 * 
	 * @see org.eclipse.birt.report.engine.excutor.ReportItemLoader#execute()