Bug 121170 get column label from meta data object should return some user recognizable strings
Calling IMetaData.getColumnLabel() before/after data extraction have different results. The labels returned before extraction are null, while the ones after extraction are recognizable strings. Since the labels need to be displayed to the end user before doing the extraction, getcolumnlabel before extraction should also return the same labels as after extraction.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/DataIterator.java
}
	public IResultMetaData getResultMetaData( ) throws BirtException
	{
		if( metaData == null )
		{
			metaData = new ResultMetaData( resultIter.getResultMetaData(), selectedColumns ); 
		}
		
		return metaData;
	}
	public boolean next( ) throws BirtException
	{
		if( isAdvanced == false)
			isAdvanced = true;
		return resultIter.next();
	}
	public Object getValue( String columnName ) throws BirtException
	{
		IBaseExpression expr = getExpression( columnName );
		
		return resultIter.getValue( expr );
	}
	
	private IBaseExpression getExpression( String columnName )
	{
		assert exprMap != null;
				
		return (IBaseExpression)exprMap.get( columnName );
	}
	public Object getValue( int index ) throws BirtException