| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * https://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| using System; |
| using System.Collections.Generic; |
| using System.Linq; |
| using Newtonsoft.Json.Linq; |
| |
| namespace Avro |
| { |
| /// <summary> |
| /// Class for union schemas |
| /// </summary> |
| public class UnionSchema : UnnamedSchema |
| { |
| /// <summary> |
| /// List of schemas in the union |
| /// </summary> |
| public IList<Schema> Schemas { get; private set; } |
| |
| /// <summary> |
| /// Count of schemas in the union |
| /// </summary> |
| public int Count { get { return Schemas.Count; } } |
| |
| /// <summary> |
| /// Static function to return instance of the union schema |
| /// </summary> |
| /// <param name="jarr">JSON object for the union schema</param> |
| /// <param name="props">dictionary that provides access to custom properties</param> |
| /// <param name="names">list of named schemas already read</param> |
| /// <param name="encspace">enclosing namespace of the schema</param> |
| /// <returns>new UnionSchema object</returns> |
| 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($"Invalid JSON in union {jvalue.ToString()} at '{jvalue.Path}'"); |
| |
| string name = unionType.Fullname; |
| if (uniqueSchemas.ContainsKey(name)) |
| throw new SchemaParseException($"Duplicate type in union: {name} at '{jvalue.Path}'"); |
| |
| uniqueSchemas.Add(name, name); |
| schemas.Add(unionType); |
| } |
| return new UnionSchema(schemas, props); |
| } |
| |
| /// <summary> |
| /// Creates a new <see cref="UnionSchema"/> |
| /// </summary> |
| /// <param name="schemas">The union schemas</param> |
| /// <param name="customProperties">Dictionary that provides access to custom properties</param> |
| /// <returns>New <see cref="UnionSchema"/></returns> |
| public static UnionSchema Create(List<Schema> schemas, PropertyMap customProperties = null) |
| { |
| return new UnionSchema(schemas, customProperties); |
| } |
| |
| /// <summary> |
| /// Contructor for union schema |
| /// </summary> |
| /// <param name="schemas"></param> |
| /// <param name="customProperties">dictionary that provides access to custom properties</param> |
| private UnionSchema(List<Schema> schemas, PropertyMap customProperties) |
| : base(Type.Union, customProperties) |
| { |
| if (schemas == null) |
| throw new ArgumentNullException(nameof(schemas)); |
| VerifyChildSchemas(schemas); |
| this.Schemas = schemas; |
| } |
| |
| /// <summary> |
| /// Returns the schema at the given branch. |
| /// </summary> |
| /// <param name="index">Index to the branch, starting with 0.</param> |
| /// <returns>The branch corresponding to the given index.</returns> |
| public Schema this[int index] |
| { |
| get |
| { |
| return Schemas[index]; |
| } |
| } |
| |
| /// <summary> |
| /// Writes union schema in JSON format |
| /// </summary> |
| /// <param name="writer">JSON writer</param> |
| /// <param name="names">list of named schemas already written</param> |
| /// <param name="encspace">enclosing namespace of the schema</param> |
| 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(); |
| } |
| |
| /// <summary> |
| /// Returns the index of a branch that can read the data written by the given schema s. |
| /// </summary> |
| /// <param name="s">The schema to match the branches against.</param> |
| /// <returns>The index of the matching branch. If non matches a -1 is returned.</returns> |
| public int MatchingBranch(Schema s) |
| { |
| if (s is UnionSchema) throw new AvroException("Cannot find a match against union schema"); |
| // Try exact match. |
| // CanRead might find a compatible schema which can read. e.g. double and long |
| for (int i = 0; i < Count; i++) |
| { |
| if (Schemas[i].Equals(s)) |
| { |
| return i; |
| } |
| } |
| for (int i = 0; i < Count; i++) |
| { |
| if (Schemas[i].CanRead(s)) |
| { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| /// <summary> |
| /// Checks if this schema can read data written by the given schema. Used for decoding data. |
| /// </summary> |
| /// <param name="writerSchema">writer schema</param> |
| /// <returns>true if this and writer schema are compatible based on the AVRO specification, false otherwise</returns> |
| public override bool CanRead(Schema writerSchema) |
| { |
| return writerSchema.Tag == Schema.Type.Union || MatchingBranch(writerSchema) >= 0; |
| } |
| |
| /// <summary> |
| /// Compares two union schema objects |
| /// </summary> |
| /// <param name="obj">union schema object to compare against this schema</param> |
| /// <returns>true if objects are equal, false otherwise</returns> |
| 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; |
| } |
| |
| /// <summary> |
| /// Hash code function |
| /// </summary> |
| /// <returns></returns> |
| public override int GetHashCode() |
| { |
| int result = 53; |
| foreach (Schema schema in Schemas) result += 89 * schema.GetHashCode(); |
| result += getHashCode(Props); |
| return result; |
| } |
| |
| private void VerifyChildSchemas(List<Schema> schemas) |
| { |
| if (schemas.Any(schema => schema.Tag == Type.Union)) |
| { |
| throw new ArgumentException("Unions may not immediately contain other unions", nameof(schemas)); |
| } |
| |
| IGrouping<string, Schema> duplicateType = schemas.GroupBy(schema => schema.Fullname).FirstOrDefault(x => x.Count() > 1); |
| |
| if (duplicateType != null) |
| { |
| throw new ArgumentException($"Duplicate type in union: {duplicateType.Key}"); |
| } |
| } |
| } |
| } |