public final class DTDId
extends Object
Simple key object class, used for accessing (external) DTDs when stored for
 caching. Main idea is that the primary id of a DTD (public or system id;
 latter normalized if possible)
 has to match, as well as couple of on/off settings for parsing (namespace
 support, text normalization).
 Latter restriction is needed since although DTDs do not deal
 with (or understand) namespaces, some parsing is done to be able to validate
 namespace aware/non-aware documents, and handling differs between the two.
 As to primary key part, public id is used if one was defined; if so,
 comparison is String equality. If not, then system id is compared: system
 id has to be expressed as URL if so.