StringLiteral.cs

using System;
using System.Text;
using Waher.Content.Semantic.Ontologies;
using Waher.Runtime.Inventory;
 
namespace Waher.Content.Semantic.Model.Literals
{
    public class StringLiteral : SemanticLiteral
    {
        private readonly string language;
 
        public StringLiteral()
            : base()
        {
            this.language = null;
        }
 
        public StringLiteral(string Value)
            : base(Value, Value)
        {
            this.language = null;
        }
 
        public StringLiteral(string Value, string Language)
            : base(Value, Value)
        {
            this.language = Language;
        }
 
        public const string TypeUri = XmlSchema.Namespace + "string";
 
        public override string StringType => string.Empty;
 
        public override Grade Supports(Type ValueType)
        {
            return ValueType == typeof(string) ? Grade.Ok : Grade.NotAtAll;
        }
 
        public string Language => this.language;
 
        public override Grade Supports(string DataType)
        {
            return string.IsNullOrEmpty(DataType) || DataType == TypeUri ? Grade.Ok : Grade.NotAtAll;
        }
 
        public override ISemanticLiteral Parse(string Value, string DataType, string Language)
        {
            return new StringLiteral(Value, Language);
        }
 
        public override ISemanticLiteral Encapsulate(object Value)
        {
            return new StringLiteral(Value?.ToString() ?? string.Empty);
        }
 
        public override string ToString()
        {
            StringBuilder sb = new StringBuilder();
 
            sb.Append('"');
            sb.Append(JSON.Encode(this.StringValue));
            sb.Append('"');
 
            if (!string.IsNullOrEmpty(this.language))
            {
                sb.Append('@');
                sb.Append(this.language);
            }
 
            return sb.ToString();
        }
 
        public override bool Equals(object obj)
        {
            return obj is StringLiteral Typed &&
                Typed.StringValue == this.StringValue &&
                string.Compare(Typed.language, this.language, true) == 0;
        }
 
        public override int GetHashCode()
        {
            int Result = this.StringValue.GetHashCode();
            Result ^= Result << 5 ^ (this.language?.GetHashCode() ?? 0);
            return Result;
        }
 
        public override int CompareTo(object obj)
        {
            if (obj is StringLiteral Typed)
            {
                int i = this.StringValue.CompareTo(Typed.StringValue);
                if (i != 0)
                    return i;
 
                return this.language?.CompareTo(Typed.language) ?? (Typed.language is null ? 0 : -1);
            }
 
            return base.CompareTo(obj);
        }
 
    }
}