Add lookup() option to print unknown values.

[blackwinter]

I've opted to reuse the file-related options from print_record(), the actual behaviour is triggered by a boolean flag (print_unknown).

Resolves #212.

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General issue: We can't differentiate between method options and a local (unnamed) map.

[blackwinter]

Oh, you were too quick ;) I forgot to mention that there's a subtle behaviour change here: If a key is associated with a null value, it's logged as unknown and the default value is returned (if given, otherwise the key is returned); previously, the key would have been returned even with a default value present. This only applies to Java maps, of course, since Fix doesn't have null values.

[fsteeg]

If a key is associated with a null value, it's logged as unknown and the default value is returned (if given, otherwise the key is returned); previously, the key would have been returned even with a default value present.

+1, sounds like an improvement!

[blackwinter]

Heads up: I think this won't work across multiple records (unless a separate file is written for each record, using counter and/or record ID). I have yet to verify, but am pretty sure ;) (see also metafacture/metafacture-core#475)

[blackwinter]

Fixed printing unknown values across multiple records in 356a5e7.

(Also rebased on top of master, i.e. 5d756eb)

[TobiasNx]

The append option is a little bit unclear. If append:"false" assumed that the file is overwritten per metafacture run not per record. But it seems that the file is overwritten per record.

See here: #270

[blackwinter]

If append:"false" assumed that the file is overwritten per metafacture run not per record.

No, with append mode disabled, the file is overwritten for every lookup() call. Otherwise, it gets appended to instead of overwritten.

But it seems that the file is overwritten per record.

Exactly, that's the expected behaviour.

(See also the unit tests.)

[TobiasNx]

If append:"false" assumed that the file is overwritten per metafacture run not per record.

anyway to make this a feature?
Use case: In OERSI every day all records are transformed. Therefore append would generate a lot of duplicates because of the daily transformation of each record.

[blackwinter]

anyway to make this a feature?

What do you have in mind? A timestamp in the file name?

Therefore append would generate a lot of duplicates because of the daily transformation of each record.

But you are going to add unknown values over time, aren't you? And then you'd delete the file.

Otherwise, I would suggest to just rotate the file.

[TobiasNx]

anyway to make this a feature?

What do you have in mind? A timestamp in the file name?

I thought to overwrite just once, the first time the lookup is run.

Therefore append would generate a lot of duplicates because of the daily transformation of each record.

But you are going to add unknown values over time, aren't you? And then you'd delete the file.

Otherwise, I would suggest to just rotate the file.

Yes I am, but I have no direct control over the productive OERSI system. I cannot delete it by my own. The deletion process would be done by the infrastructure and the rotation need be prepared by @fsteeg then.

[blackwinter]

I thought to overwrite just once, the first time the lookup is run.

We can try if that's the requirement.

@fsteeg: Want to weigh in?

[TobiasNx]

I thought to overwrite just once, the first time the lookup is run.

We can try if that's the requirement.

@fsteeg: Want to weigh in?

If this is to much hastle. Let's go with this as it is for now, and evaluate later if this is a needed feature!

One other thing. I tried to set id to name but the printed output has not the value of name in it:
#270

[blackwinter]

One further thing. I tried to set id to name but the printed output has not the value of name in it: #270

1. The record ID is not included in the output, it's only meant for inclusion in the file name (destination).
2. It's actually not implemented as documented right now. Going to fix.

[blackwinter]

Fixed destination and also added prefix option (same as print_record()'s prefix parameter).

[blackwinter]

Let's go with this as it is for now, and evaluate later if this is a needed feature!

That's fine with me, but we should keep in mind that such a change might not be possible in a backwards-compatible manner.