Don't throw exception when encountering invalid query terms

[kwahlin]

Proceed with the query in the usual way (we won't get any hits though), however mark the invalid parts in search.mapping like this:

{
    "@type": "_Invalid",
    "label": "theInvalidInputString"
}

This can apply to both keys and values. So if we type for example type:Kalle x:y subject:horses we get

"search": {
    "mapping": [
      {
        "and": [
          {
            "property": {
              "@id": "http://www.w3.org/1999/02/22-rdf-syntax-ns#type",
              "@type": "ObjectProperty",
              "labelByLang": {
                "en": "type",
                "sv": "typ"
              }
            },
            "equals": {
              "@type": "_Invalid",
              "label": "Kalle"
            },
            "up": {
              "@id": "/find?_i=&_q=x:y+subject:horses&_limit=200"
            }
          },
          {
            property": {
              "@type": "_Invalid",
              "label": "x"
            },
            "equals": "y",
            "up": {
              "@id": "/find?_i=&_q=%22rdf:type%22:Kalle+subject:horses&_limit=200"
            }
          },
          {
            "property": {
              "@id": "https://id.kb.se/vocab/subject",
              "@type": "ObjectProperty",
               ...
            },
            "equals": "horses",
            "up": {
              "@id": "/find?_i=&_q=%22rdf:type%22:Kalle+x:y&_limit=200"
            }
          }
        ],
        "up": {
          "@id": "/find?_i=&_q=*&_limit=200"
        }
      }
    ]
  }

since x is an invalid key and Kalle is and invalid value for the property rdf:type.

Eventually we may need more details about why a certain string is invalid and, consequently, also a more expressive model. Let's see. Stick with the temporary _Invalid type for now.

[olovy]

LGTM!

Perhaps InvalidKey could be aligned with Property so that the don't have to be treated separately in this part of the code?

i.e.

interface Foo { 
    String name();
    Map<String, Object> definition();
}

public class Property implements Foo { ... }

public sealed interface InvalidKey extends Foo { ... }

[olovy]

LGTM!

Perhaps InvalidKey could be aligned with Property so that the don't have to be treated separately in this part of the code?

i.e.

interface Foo { 
    String name();
    Map<String, Object> definition();
}

public class Property implements Foo { ... }

public sealed interface InvalidKey extends Foo { ... }

for example #1543