Redesign user-filter security mechanism

[SlowMo24]

The current design choice to prevent accidental exposure of the user-filter provides two default filter mechanisms

.filter(filterString)

and

String filterText = …;
TagTranslator tagTranslator = …;
FilterParser parser = new FilterParser(tagTranslator);
FilterExpression filter = parser.parse(filterText);

... 
.filter(filter)
...

and one with activated user-filtering

String filterText = …;
TagTranslator tagTranslator = …;
FilterParser parser = new FilterParser(tagTranslator, true);
FilterExpression filter = parser.parse(filterText);

This design choice seems peculiar because it hides a useful functionality by default and it does not add any security but rather tries to prevents coding errors in depending tools such as the ohsome-api.

The following are some alternative designs that may be preferable:

• Inverse the above and don't hide a function by default but hide it on request.
• put the activation functionality directly to the method

  .filter(filterString, booleanContributorFilterAllowed)
  

• the above but use an enum instead of a boolean for later flexibility
• use different method names (filter and filterWithContributor for example)

//cc @sfendrich what are your opinions as design-specialist?

[SlowMo24]

Another very minor thing: the word optional is not directly clear in the changelog: (optional) contributor: <id|(ids)>. All filters are optional, right?

Also this information (disabled by default, can be activated by creating a filter parser with the respective optional boolean flag enabled) in the respective pull request did not make it to the explanation here: https://github.com/GIScience/oshdb/blob/master/oshdb-filter/README.md

[Hagellach37]

not planned, as users of the OSHDB should be aware of the issue and act accordinly