Bug 141064 Remove group level data binding
This bug covers the engine part of the task to remove group level data binding. After the hange, all binding expressions will be defined on the table level, and each binding expression will have an AggregateOn field to explicitly define the group level for that expression.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/data/dte/ReportQueryBuilder.java
transferExpressions( cell );
			for ( int i = 0; i < cell.getContentCount( ); i++ )
				cell.getContent( i ).accept( this, value );
		}
		protected void pushReportItemQuery( IBaseQueryDefinition query )
		{
			if ( this.reportItemQueryStack == null )
			{
				this.reportItemQueryStack = new LinkedList( );
			}
			this.reportItemQueryStack.addLast( query );
		}
		protected void popReportItemQuery( )
		{
			assert this.reportItemQueryStack.isEmpty( ) == false;
			this.reportItemQueryStack.removeLast( );
		}
		/**
		 * A helper function for adding a query to query stack
		 */
		protected void pushQuery( IBaseTransform query )
		{
			this.queryStack.addLast( query );
		}
		/**
		 * A helper function for removing a query from query stack
		 */
		protected void popQuery( )
		{
			assert !queryStack.isEmpty( );