Util/SemWeb/NamespaceManager.cs

   1 using System;
   2 using System.Collections;
   3
   4 namespace SemWeb {
   5
   6         internal class NS {
   7                 public const string RDF = "http://www.w3.org/1999/02/22-rdf-syntax-ns#";
   8                 public const string RDFS = "http://www.w3.org/2000/01/rdf-schema#";
   9
  10                 /*Entity entRDFTYPE = "http://www.w3.org/1999/02/22-rdf-syntax-ns#type";
  11                 Entity entRDFFIRST = "http://www.w3.org/1999/02/22-rdf-syntax-ns#first";
  12                 Entity entRDFREST = "http://www.w3.org/1999/02/22-rdf-syntax-ns#rest";
  13                 Entity entRDFNIL = "http://www.w3.org/1999/02/22-rdf-syntax-ns#nil";
  14                 Entity entOWLSAMEAS = "http://www.w3.org/2002/07/owl#sameAs";
  15                 Entity entLOGIMPLIES = "http://www.w3.org/2000/10/swap/log#implies";*/
  16         }
  17
  18         public class NamespaceManager {
  19                 NamespaceManager parent;
  20                 Hashtable atob = new Hashtable();
  21                 Hashtable btoa = new Hashtable();
  22
  23                 public NamespaceManager() : this (null) {
  24                 }
  25
  26                 public NamespaceManager(NamespaceManager parent) {
  27                         this.parent = parent;
  28                 }
  29
  30                 public void AddNamespace(string uri, string prefix) {
  31                         atob[uri] = prefix;
  32                         btoa[prefix] = uri;
  33                 }
  34
  35                 public virtual string GetNamespace(string prefix) {
  36                         string ret = (string)btoa[prefix];
  37                         if (ret != null) return ret;
  38                         if (parent != null) return parent.GetNamespace(prefix);
  39                         return null;
  40                 }
  41
  42                 public virtual string GetPrefix(string uri) {
  43                         string ret = (string)atob[uri];
  44                         if (ret != null) return ret;
  45                         if (parent != null) return parent.GetPrefix(uri);
  46                         return null;
  47                 }
  48
  49                 public bool Normalize(string uri, out string prefix, out string localname) {
  50                         int hash = uri.LastIndexOf('#');
  51                         if (hash > 0) {
  52                                 prefix = GetPrefix(uri.Substring(0, hash+1));
  53                                 if (prefix != null) {
  54                                         localname = uri.Substring(hash+1);
  55                                         return true;
  56                                 }
  57                         }
  58
  59                         hash = uri.LastIndexOf('/');
  60                         if (hash > 0) {
  61                                 prefix = GetPrefix(uri.Substring(0, hash+1));
  62                                 if (prefix != null) {
  63                                         localname = uri.Substring(hash+1);
  64                                         return true;
  65                                 }
  66                         }
  67
  68                         prefix = null;
  69                         localname = null;
  70
  71                         return false;
  72                 }
  73
  74                 public string Normalize(string uri) {
  75                         string prefix, localname;
  76                         if (Normalize(uri, out prefix, out localname)) {
  77                                 bool ok = true;
  78                                 if (localname.Length == 0) ok = false;
  79                                 else if (!char.IsLetter(localname[0])) ok = false;
  80                                 foreach (char c in localname)
  81                                         if (!char.IsLetterOrDigit(c) && c != '-' && c != '_')
  82                                                 ok = false;
  83                                 if (ok)
  84                                         return prefix + ":" + localname;
  85                         }
  86                         return "<" + uri + ">";
  87                 }
  88
  89                 public string Resolve(string qname) {
  90                         int colon = qname.IndexOf(':');
  91                         if (colon == -1) throw new ArgumentException("Invalid qualified name.");
  92                         string prefix = qname.Substring(0, colon);
  93                         string ns = GetNamespace(prefix);
  94                         if (ns == null) throw new ArgumentException("The prefix " + prefix + " is not declared.");
  95                         return ns + qname.Substring(colon+1);
  96                 }
  97
  98                 public ICollection GetNamespaces() {
  99                         if (parent == null) return atob.Keys;
 100                         ArrayList items = new ArrayList(atob.Keys);
 101                         foreach (string ns in parent.GetNamespaces())
 102                                 if (!items.Contains(ns))
 103                                         items.Add(ns);
 104                         return items;
 105                 }
 106
 107                 public ICollection GetPrefixes() {
 108                         if (parent == null) return atob.Values;
 109                         ArrayList items = new ArrayList(atob.Values);
 110                         foreach (string ns in parent.GetPrefixes())
 111                                 if (!items.Contains(ns))
 112                                         items.Add(ns);
 113                         return items;
 114                 }
 115         }
 116 }
 117
 118 namespace SemWeb.IO {
 119         using SemWeb;
 120
 121         internal class AutoPrefixNamespaceManager : NamespaceManager {
 122                 int counter = 0;
 123
 124                 public AutoPrefixNamespaceManager() : this (null) {
 125                 }
 126
 127                 public AutoPrefixNamespaceManager(NamespaceManager parent) : base(parent) {
 128                 }
 129
 130                 public override string GetPrefix(string uri) {
 131                         string ret = base.GetPrefix(uri);
 132                         if (ret != null) return ret;
 133
 134                         if (uri == "http://www.w3.org/1999/02/22-rdf-syntax-ns#" && GetNamespace("rdf") == null)
 135                                 ret = "rdf";
 136                         else if (uri == "http://www.w3.org/2000/01/rdf-schema#" && GetNamespace("rdfs") == null)
 137                                 ret = "rdfs";
 138                         else if (uri == "http://www.w3.org/2002/07/owl#" && GetNamespace("owl") == null)
 139                                 ret = "owl";
 140                         else if (uri == "http://purl.org/dc/elements/1.1/" && GetNamespace("dc") == null)
 141                                 ret = "dc";
 142                         else if (uri == "http://xmlns.com/foaf/0.1/" && GetNamespace("foaf") == null)
 143                                 ret = "foaf";
 144                         else
 145                                 ret = "autons" + (counter++);
 146                         AddNamespace(uri, ret);
 147                         return ret;
 148                 }
 149         }
 150 }