1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
#region Copyright notice and license
// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// http://github.com/jskeet/dotnet-protobufs/
// Original C++/Java/Python code:
// http://code.google.com/p/protobuf/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#endregion
using System;
using System.Reflection;
namespace Google.ProtocolBuffers
{
/// <summary>
/// Utilities for arbitrary messages of an unknown type. This class does not use
/// generics precisely because it is designed for dynamically discovered types.
/// </summary>
public static class MessageUtil
{
/// <summary>
/// Returns the default message for the given type. If an exception is thrown
/// (directly from this code), the message will be suitable to be displayed to a user.
/// </summary>
/// <param name="type"></param>
/// <exception cref="ArgumentNullException">The type parameter is null.</exception>
/// <exception cref="ArgumentException">The type doesn't implement IMessage, or doesn't
/// have a static DefaultMessage property of the same type, or is generic or abstract.</exception>
/// <returns></returns>
public static IMessage GetDefaultMessage(Type type)
{
if (type == null)
{
throw new ArgumentNullException("type", "No type specified.");
}
if (type.IsAbstract || type.IsGenericTypeDefinition)
{
throw new ArgumentException("Unable to get a default message for an abstract or generic type (" +
type.FullName + ")");
}
if (!typeof(IMessage).IsAssignableFrom(type))
{
throw new ArgumentException("Unable to get a default message for non-message type (" + type.FullName +
")");
}
PropertyInfo property = type.GetProperty("DefaultInstance",
BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);
if (property == null)
{
throw new ArgumentException(type.FullName + " doesn't have a static DefaultInstance property");
}
if (property.PropertyType != type)
{
throw new ArgumentException(type.FullName + ".DefaultInstance property is of the wrong type");
}
return (IMessage) property.GetValue(null, null);
}
/// <summary>
/// Returns the default message for the type with the given name. This is just
/// a convenience wrapper around calling Type.GetType and then GetDefaultMessage.
/// If an exception is thrown, the message will be suitable to be displayed to a user.
/// </summary>
/// <param name="typeName"></param>
/// <exception cref="ArgumentNullException">The typeName parameter is null.</exception>
/// <exception cref="ArgumentException">The type doesn't implement IMessage, or doesn't
/// have a static DefaultMessage property of the same type, or can't be found.</exception>
public static IMessage GetDefaultMessage(string typeName)
{
if (typeName == null)
{
throw new ArgumentNullException("typeName", "No type name specified.");
}
Type type = Type.GetType(typeName);
if (type == null)
{
throw new ArgumentException("Unable to load type " + typeName);
}
return GetDefaultMessage(type);
}
}
}
|
