Bug 112287 It's better to transfer to "new data source" dialog when creating a new data set without existing data source.
Description: It's better to transfer to "new data source" dialog automatically when creating a new data set without existing data source. Steps to reproduce: 1. There is no existing data source. 2. Create a new data set. 3. It pops up hint message, saying that "there is no data source". Actual result: it's better to transfer to "new data source" dialog box now and help users create a new data source.
chart/org.eclipse.birt.chart.reportitem.ui/src/org/eclipse/birt/chart/reportitem/ui/ReportDataServiceProvider.java
ArrayList list = new ArrayList( );
		while ( iterator.hasNext( ) )
		{
			list.add( ( (ComputedColumnHandle) iterator.next( ) ).getName( ) );
		}
		return (String[]) list.toArray( new String[list.size( )] );
	}
	public final List getPreviewData( ) throws ChartException
	{
		return getPreviewRowData( getPreviewHeader( true ), -1, true );
	}
	private String[] getPreviewHeader( boolean isExpression )
			throws ChartException
	{
		String[] exps = getPreviewHeader( );
		if ( isExpression )
		{
			for ( int i = 0; i < exps.length; i++ )
			{
				exps[i] = ChartUIUtil.getExpressionString( exps[i] );
			}
		}
		return exps;
	}
	protected final List getPreviewRowData( String[] columnExpression,
			int rowCount, boolean isStringType ) throws ChartException
	{
		ArrayList dataList = new ArrayList( );