FullTextSearchAttribute.cs

using System;
using System.Reflection;
 
namespace Waher.Persistence.FullTextSearch
{
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, AllowMultiple = true, Inherited = true)]
    public class FullTextSearchAttribute : Attribute
    {
        private readonly string indexCollection;
        private readonly PropertyDefinition[] properties;
        private readonly bool hasPropertyDefinitions;
        private readonly bool isPropertyReference;
 
        public FullTextSearchAttribute(string IndexCollection)
            : this(IndexCollection, new PropertyDefinition[0])
        {
        }
 
        public FullTextSearchAttribute(string IndexCollection, params string[] Properties)
            : this(IndexCollection, PropertyDefinition.ToArray(Properties))
        {
        }
 
        public FullTextSearchAttribute(string IndexCollection, params PropertyDefinition[] Properties)
        {
            this.indexCollection = IndexCollection;
            this.properties = Properties;
            this.hasPropertyDefinitions = (Properties?.Length ?? 0) > 0;
            this.isPropertyReference = false;
        }
 
        public FullTextSearchAttribute(string IndexCollection, bool PropertyReference)
        {
            this.indexCollection = IndexCollection;
            this.properties = new PropertyDefinition[0];
            this.hasPropertyDefinitions = (this.Properties?.Length ?? 0) > 0;
            this.isPropertyReference = PropertyReference;
        }
 
        public bool DynamicIndexCollection => this.isPropertyReference;
 
        public string GetIndexCollection(object Reference)
        {
            if (this.isPropertyReference)
            {
                Type T = Reference.GetType();
                PropertyInfo PI = T.GetRuntimeProperty(this.indexCollection)
                    ?? throw new ArgumentException("Object lacks a property named " + this.indexCollection, nameof(Reference));
 
                object Obj = PI.GetValue(Reference);
 
                if (Obj is string s)
                    return s;
                else
                    throw new ArgumentException("Object property " + this.indexCollection + " does not return a string.", nameof(Reference));
            }
            else
                return this.indexCollection;
        }
 
        public PropertyDefinition[] Properties => this.properties;
 
        public bool HasPropertyDefinitions => this.hasPropertyDefinitions;
    }
}