Bug 180608 [Regression]NPE throws out when preview the result in dataset[07]
Description: [Regression]NPE throws out when preview the result in dataset[07] Build number: 2.2.0.v20070403-0630 Steps to reproduce: 1, Use attached report 2, Edit Data Set 3, Preview the Data Set Expected result: The preview should be success Actual result: NPE throws out Error log:
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/executor/ResultClass.java
{
		return projectedCols[index - 1].getName();
	}
	public String getFieldAlias( int index ) throws DataException
	{
		return projectedCols[index - 1].getAlias();
	}
	
	public int getFieldIndex( String fieldName )
	{
		Integer i = 
			(Integer) nameToIdMapping.get( fieldName );
		return ( i == null ) ? -1 : i.intValue();
	}
	
	private int doGetFieldIndex( String fieldName ) throws DataException
	{
		int index = getFieldIndex( fieldName );
		
		if( index <= 0 )
			throw new DataException( ResourceConstants.INVALID_FIELD_NAME, fieldName );
		
		return index;
	}
	public Class getFieldValueClass( String fieldName ) throws DataException
	{
		int index = doGetFieldIndex( fieldName );
		return getFieldValueClass( index );
	}
	public Class getFieldValueClass( int index ) throws DataException