UnionSchema.cs

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using System;
using System.Collections.Generic;
using System.Text;
using Newtonsoft.Json.Linq;
using Newtonsoft.Json;

namespace Avro
{
    public class UnionSchema : UnnamedSchema
    {
        public IList<Schema> Schemas { get; private set; }

        public int Count { get { return Schemas.Count; } }

        internal static UnionSchema NewInstance(JArray jarr, PropertyMap props, SchemaNames names, string encspace)
        {
            List<Schema> schemas = new List<Schema>();
            IDictionary<string, string> uniqueSchemas = new Dictionary<string, string>();

            foreach (JToken jvalue in jarr)
            {
                Schema unionType = Schema.ParseJson(jvalue, names, encspace);
                if (null == unionType)
                    throw new SchemaParseException("Invalid JSON in union" + jvalue.ToString());

                string name = unionType.Name;
                if (uniqueSchemas.ContainsKey(name))
                    throw new SchemaParseException("Duplicate type in union: " + name);

                uniqueSchemas.Add(name, name);
                schemas.Add(unionType);
            }

            return new UnionSchema(schemas, props);
        }

        private UnionSchema(List<Schema> schemas, PropertyMap props) : base(Type.Union, props)
        {
            if (schemas == null)
                throw new ArgumentNullException("schemas");
            this.Schemas = schemas;
        }

        public Schema this[int index]
        {
            get
            {
                return Schemas[index];
            }
        }

        protected internal override void WriteJson(Newtonsoft.Json.JsonTextWriter writer, SchemaNames names, string encspace)
        {
            writer.WriteStartArray();
            foreach (Schema schema in this.Schemas)
                schema.WriteJson(writer, names, encspace);
            writer.WriteEndArray();
        }

        public int MatchingBranch(Schema s)
        {
            if (s is UnionSchema) throw new AvroException("Cannot find a match against union schema");
            // Try exact match.
            //for (int i = 0; i < Count; i++) if (Schemas[i].Equals(s)) return i; // removed this for performance's sake
            for (int i = 0; i < Count; i++) if (Schemas[i].CanRead(s)) return i;
            return -1;
        }

        public override bool CanRead(Schema writerSchema)
        {
            return writerSchema.Tag == Schema.Type.Union || MatchingBranch(writerSchema) >= 0;
        }

        public override bool Equals(object obj)
        {
            if (obj == this) return true;
            if (obj != null && obj is UnionSchema)
            {
                UnionSchema that = obj as UnionSchema;
                if (that.Count == Count)
                {
                    for (int i = 0; i < Count; i++) if (!that[i].Equals(this[i])) return false;
                    return areEqual(that.Props, this.Props);
                }
            }
            return false;
        }

        public override int GetHashCode()
        {
            int result = 53;
            foreach (Schema schema in Schemas) result += 89 * schema.GetHashCode();
            result += getHashCode(Props);
            return result;
        }
    }
}