context.getSelectedHeaders() in RowProcessor processStarted() can return invalid results

[efrench-novi]

If you call context.getSelectedHeaders() and the header has not yet been extracted by the read input thread (which means extractedFieldIndexes will be null), it will force the header extraction, but return the extracted headers and not the selectedHeaders (see code below).

To work around you can call context.parsedHeaders() or context.headers() first, which will force header extraction, after which context.getSelectedHeaders() will return the correct values.

Debug output calling context.selectedHeaders() multiple times shows this (the first line is from outside of the parser prior to calling parse()).

loadTable columns: [a, c, e]

rowProcessor.processStarted()
context.extractedFieldIndexes(): null
context.selectedHeaders(): [a, b, c, d, e]
context.selectedHeaders(): [a, c, e]
context.extractedFieldIndexes(): [I@51555c54

The DefaultContext selectedHeaders() method:

    public String[] selectedHeaders() {
		int[] extractedFieldIndexes = extractedFieldIndexes();
		if (extractedFieldIndexes != null) {
			String[] extractedFields = new String[extractedFieldIndexes.length];
			String[] headers = headers();
			for (int i = 0; i < extractedFieldIndexes.length; i++) {
				extractedFields[i] = headers[extractedFieldIndexes[i]];
			}
			return extractedFields;
		}
		return headers();
	}

I can think of two simple ways to address the issue:

1. The AbstractParser parser could call extractHeadersIfNeeded() prior to calling processStarted IF parserSettings has selectedFields.
2. DefaultContext selectedHeaders() call could call headers() first, and then check extractedFieldIndexes() to see if not null

[jbax]

Thank you for reporting the issue and for giving the proposed solutions. I went with option 2 :)

I also released version 2.9.1-SNAPSHOT for you to test.

Thank you for using our parsers!