public void addDocument(ParsedDocument document) {
        verifyThat(myDocument == null,
                   "already has", myDocument, "so cannot add", document);
        // TODO - disallow?
        // verifyThat(name().equals(document.name()),
        // "schema " + name() + " can only contain document named " + name() + ", was: "+ document.name());
        this.myDocument = document;
    }
This class holds the extracted information after parsing
one schema (.sd) file, using simple data structures
as far as possible.

Do not put complicated logic here!

@author arnej27959
config-model/src/main/java/com/yahoo/schema/parser/ParsedSchema.java