Counted leader elements in marc when encoding to marc

[TobiasNx]

@maipet hinted that encode-marc21 or encode-marcxml cannot create the leader correctly since the elements are not counted.
Could you elaborate the problem

[blackwinter]

Is this related to #454?

[TobiasNx]

I am not sure. We are transforming the OERSI JSON Data to Marc, but @maipet told me about invalid results created by the transformation due to the missing leader elements that state e.g. the length of a record.

But @maipet could clarify.

[maipet]

you can set the leader field, but leader "Character Positions 00-04 - Record length" & "Pos. 12-16 - Base address of data" should actually be generated automatically? It was discussed with @dr0i that we should first check whether the marc records from OERSI are 'valid' even without the correct information in the leader (the positions are currently filled with zeros).

[TobiasNx]

While inspecting some workaround for #454, I saw that the marc21-encoder seems to have a mechanism for that:

https://metafacture.org/playground/?flux=%22https%3A//d-nb.info/1106253078/about/marcxml%22%0A%7C+open-http%28accept%3D%22application/xml%22%29%0A%7C+decode-xml%0A%7C+handle-marcxml%0A%7C+fix%28transformationFile%29%0A%7C+encode-marc21%0A%7C+decode-marc21%28emitLeaderAsWhole%3D%22true%22%29%0A%7C+encode-yaml%0A%7C+print%0A%3B&transformation=copy_field%28%22leader%22%2C%22@leader.status%22%29%0Acopy_field%28%22leader%22%2C%22@leader.type%22%29%0Acopy_field%28%22leader%22%2C%22@leader.bibliographicLevel%22%29%0Acopy_field%28%22leader%22%2C%22@leader.typeOfControl%22%29%0Acopy_field%28%22leader%22%2C%22@leader.characterCodingScheme%22%29%0Acopy_field%28%22leader%22%2C%22@leader.encodingLevel%22%29%0Acopy_field%28%22leader%22%2C%22@leader.catalogingForm%22%29%0Acopy_field%28%22leader%22%2C%22@leader.multipartLevel%22%29%0A%0Asubstring%28%22@leader.status%22%2C%225%22%2C%221%22%29%0Asubstring%28%22@leader.type%22%2C%226%22%2C%221%22%29%0Asubstring%28%22@leader.bibliographicLevel%22%2C%227%22%2C%221%22%29%0Asubstring%28%22@leader.typeOfControl%22%2C%228%22%2C%221%22%29%0Asubstring%28%22@leader.characterCodingScheme%22%2C%229%22%2C%221%22%29%0Asubstring%28%22@leader.encodingLevel%22%2C%2217%22%2C%221%22%29%0Asubstring%28%22@leader.catalogingForm%22%2C%2218%22%2C%221%22%29%0Asubstring%28%22@leader.multipartLevel%22%2C%2219%22%2C%221%22%29%0A%0Amove_field%28%22@leader%22%2C%22leader%22%29

Someone more advanced should have a look to confirm. Probably we could reuse the parts of the encode-marc21 for encode-marcxml

[dr0i]

The construction of the leader (counting bytes including indicators etc magic) is done through invoking Marc21Decoder.java (which calls the Record.java) . Code can be reused for encode-marc21 - although it's ugly from a performance point of view (the whole record has to be made into tpye Record at the end of the parsing of a record).
This will be done in my PR treating #454.

[TobiasNx]

Code can be reused for encode-marc21

@dr0i: Isn't encode-marc21 already doing this? See: #524 (comment)