Util/SemWeb/Statement.cs

   1 using System;
   2
   3 namespace SemWeb {
   4         public struct Statement {
   5                 private Entity s;
   6                 private Entity p;
   7                 private Resource o;
   8                 private Entity m;
   9
  10                 public static Entity DefaultMeta = new Entity(null);
  11
  12                 public Statement(Entity subject, Entity predicate, Resource @object)
  13                 : this(subject, predicate, @object, DefaultMeta) {
  14                 }
  15
  16                 public Statement(Entity subject, Entity predicate, Resource @object, Entity meta) {
  17                   s = subject;
  18                   p = predicate;
  19                   o = @object;
  20                   m = meta;
  21                 }
  22
  23                 public Entity Subject { get { return s; } }
  24                 public Entity Predicate { get { return p; } }
  25                 public Resource Object { get { return o; } }
  26
  27                 public Entity Meta { get { return m; } }
  28
  29                 internal bool AnyNull {
  30                         get {
  31                                 return Subject == null || Predicate == null || Object == null || Meta == null;
  32                         }
  33                 }
  34
  35                 public Statement Invert() {
  36                         if (!(Object is Entity)) throw new ArgumentException("The object of the statement must be an entity.");
  37                         return new Statement((Entity)Object, Predicate, Subject, Meta);
  38                 }
  39
  40                 public bool Matches(Statement statement) {
  41                         if (Subject != null && Subject != statement.Subject) return false;
  42                         if (Predicate != null && Predicate != statement.Predicate) return false;
  43                         if (Object != null && Object != statement.Object) return false;
  44                         if (Meta != null && Meta != statement.Meta) return false;
  45                         return true;
  46                 }
  47
  48                 public override string ToString() {
  49                         string ret = "";
  50                         if (Subject != null) ret += "<" + Subject + "> "; else ret += "? ";
  51                         if (Predicate != null) ret += "<" + Predicate + "> "; else ret += "? ";
  52                         if (Object != null) {
  53                                 if (Object is Literal)
  54                                         ret += Object;
  55                                 else
  56                                         ret += "<" + Object + ">";
  57                         } else {
  58                                 ret += "?";
  59                         }
  60                         if (Meta != null && Meta != DefaultMeta) ret += " meta=<" + Meta + ">";
  61                         return ret + ".";
  62                 }
  63
  64                 public override bool Equals(object other) {
  65                         return (Statement)other == this;
  66                 }
  67
  68                 public override int GetHashCode() {
  69                         int ret = 0;
  70                         if (s != null) ret = unchecked(ret + s.GetHashCode());
  71                         if (p != null) ret = unchecked(ret + p.GetHashCode());
  72                         if (o != null) ret = unchecked(ret + o.GetHashCode());
  73                         if (m != null) ret = unchecked(ret + m.GetHashCode());
  74                         return ret;
  75                 }
  76
  77                 public static bool operator ==(Statement a, Statement b) {
  78                         if ((a.Subject == null) != (b.Subject == null)) return false;
  79                         if ((a.Predicate == null) != (b.Predicate == null)) return false;
  80                         if ((a.Object == null) != (b.Object == null)) return false;
  81                         if ((a.Meta == null) != (b.Meta == null)) return false;
  82                         if (a.Subject != null && !a.Subject.Equals(b.Subject)) return false;
  83                         if (a.Predicate != null && !a.Predicate.Equals(b.Predicate)) return false;
  84                         if (a.Object != null && !a.Object.Equals(b.Object)) return false;
  85                         if (a.Meta != null && !a.Meta.Equals(b.Meta)) return false;
  86                         return true;
  87                 }
  88                 public static bool operator !=(Statement a, Statement b) {
  89                         return !(a == b);
  90                 }
  91         }
  92
  93         public struct SelectPartialFilter {
  94                 bool s, p, o, m;
  95                 bool first;
  96
  97                 public static readonly SelectPartialFilter All = new SelectPartialFilter(true, true, true, true);
  98
  99                 public SelectPartialFilter(bool subject, bool predicate, bool @object, bool meta) {
 100                         s = subject;
 101                         p = predicate;
 102                         o = @object;
 103                         m = meta;
 104
 105                         first = false;
 106                 }
 107
 108                 public bool Subject { get { return s; } }
 109                 public bool Predicate { get { return p; } }
 110                 public bool Object { get { return o; } }
 111                 public bool Meta { get { return m; } }
 112
 113                 public bool SelectAll { get { return s && p && o && m; } }
 114                 public bool SelectNone { get { return !s && !p && !o && !m; } }
 115
 116                 public bool SelectFirst { get { return first; } set { first = value; } }
 117
 118                 public override string ToString() {
 119                         if (SelectAll) return "All";
 120                         if (SelectNone) return "None";
 121                         string ret = "";
 122                         if (Subject) ret += "S";
 123                         if (Predicate) ret += "P";
 124                         if (Object) ret += "O";
 125                         if (Meta) ret += "M";
 126                         return ret;
 127                 }
 128         }
 129 }