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1 | // Licensed to the Apache Software Foundation (ASF) under one or more |
2 | // contributor license agreements. See the NOTICE file distributed with | |
3 | // this work for additional information regarding copyright ownership. | |
4 | // The ASF licenses this file to You under the Apache License, Version 2.0 | |
5 | // (the "License"); you may not use this file except in compliance with | |
6 | // the License. You may obtain a copy of the License at | |
7 | // | |
8 | // http://www.apache.org/licenses/LICENSE-2.0 | |
9 | // | |
10 | // Unless required by applicable law or agreed to in writing, software | |
11 | // distributed under the License is distributed on an "AS IS" BASIS, | |
12 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | // See the License for the specific language governing permissions and | |
14 | // limitations under the License. | |
15 | ||
16 | using System; | |
17 | using System.Collections.Generic; | |
18 | using System.Diagnostics; | |
19 | using System.Linq; | |
20 | ||
21 | namespace Apache.Arrow | |
22 | { | |
23 | public partial class Schema | |
24 | { | |
25 | public IReadOnlyDictionary<string, Field> Fields | |
26 | { | |
27 | get => _fieldsDictionary; | |
28 | } | |
29 | ||
30 | private readonly Dictionary<string, Field> _fieldsDictionary; | |
31 | ||
32 | public IReadOnlyDictionary<string, string> Metadata { get; } | |
33 | ||
34 | public bool HasMetadata => | |
35 | Metadata != null && Metadata.Count > 0; | |
36 | ||
37 | private readonly IList<Field> _fields; | |
38 | ||
39 | public Schema( | |
40 | IEnumerable<Field> fields, | |
41 | IEnumerable<KeyValuePair<string, string>> metadata) | |
42 | { | |
43 | if (fields == null) | |
44 | { | |
45 | throw new ArgumentNullException(nameof(fields)); | |
46 | } | |
47 | ||
48 | _fields = fields.ToList(); | |
49 | ||
50 | _fieldsDictionary = fields.ToDictionary( | |
51 | field => field.Name, field => field, | |
52 | StringComparer.OrdinalIgnoreCase); | |
53 | ||
54 | Metadata = metadata?.ToDictionary(kv => kv.Key, kv => kv.Value); | |
55 | } | |
56 | ||
57 | internal Schema(List<Field> fields, IReadOnlyDictionary<string, string> metadata, bool copyCollections) | |
58 | { | |
59 | Debug.Assert(fields != null); | |
60 | Debug.Assert(copyCollections == false, "This internal constructor is to not copy the collections."); | |
61 | ||
62 | _fields = fields; | |
63 | ||
64 | _fieldsDictionary = fields.ToDictionary( | |
65 | field => field.Name, field => field, | |
66 | StringComparer.OrdinalIgnoreCase); | |
67 | ||
68 | Metadata = metadata; | |
69 | } | |
70 | ||
71 | public Field GetFieldByIndex(int i) | |
72 | { | |
73 | return _fields[i]; | |
74 | } | |
75 | ||
76 | public Field GetFieldByName(string name) => | |
77 | Fields.TryGetValue(name, out Field field) ? field : null; | |
78 | ||
79 | public int GetFieldIndex(string name, StringComparer comparer = default) | |
80 | { | |
81 | if (comparer == null) | |
82 | comparer = StringComparer.CurrentCulture; | |
83 | ||
84 | return _fields.IndexOf( | |
85 | _fields.Single(x => comparer.Compare(x.Name, name) == 0)); | |
86 | } | |
87 | ||
88 | public Schema RemoveField(int fieldIndex) | |
89 | { | |
90 | if (fieldIndex < 0 || fieldIndex >= _fields.Count) | |
91 | { | |
92 | throw new ArgumentException("Invalid fieldIndex", nameof(fieldIndex)); | |
93 | } | |
94 | ||
95 | IList<Field> fields = Utility.DeleteListElement(_fields, fieldIndex); | |
96 | ||
97 | return new Schema(fields, Metadata); | |
98 | } | |
99 | ||
100 | public Schema InsertField(int fieldIndex, Field newField) | |
101 | { | |
102 | newField = newField ?? throw new ArgumentNullException(nameof(newField)); | |
103 | if (fieldIndex < 0 || fieldIndex > _fields.Count) | |
104 | { | |
105 | throw new ArgumentException(nameof(fieldIndex), $"Invalid fieldIndex {fieldIndex} passed in to Schema.AddField"); | |
106 | } | |
107 | ||
108 | IList<Field> fields = Utility.AddListElement(_fields, fieldIndex, newField); | |
109 | ||
110 | return new Schema(fields, Metadata); | |
111 | } | |
112 | ||
113 | public Schema SetField(int fieldIndex, Field newField) | |
114 | { | |
115 | if (fieldIndex <0 || fieldIndex >= Fields.Count) | |
116 | { | |
117 | throw new ArgumentException($"Invalid fieldIndex {fieldIndex} passed in to Schema.SetColumn"); | |
118 | } | |
119 | ||
120 | IList<Field> fields = Utility.SetListElement(_fields, fieldIndex, newField); | |
121 | ||
122 | return new Schema(fields, Metadata); | |
123 | } | |
124 | } | |
125 | } |