Bug 202254 Exception is thrown when category values are null and type of X axis is set to DateTime
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/computation/DataSetIterator.java
}
			else if ( iContentType == IConstants.PRIMITIVE_ARRAY )
			{
				return nextPrimitiveDateTime( );
			}
		}
		else if ( iDataType == IConstants.TEXT )
		{
			return nextText( );
		}
		else
		
		{
			return nextObject( );
		}
		return null;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see java.util.Iterator#remove()
	 */
	public void remove( )
	{
		
	}
	/**
	 * 
	 * @return
	 */