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comparison tango/tango/net/cluster/NetworkRegistry.d @ 132:1700239cab2e trunk

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[svn r136] MAJOR UNSTABLE UPDATE!!! Initial commit after moving to Tango instead of Phobos. Lots of bugfixes... This build is not suitable for most things.
author lindquist
date Fri, 11 Jan 2008 17:57:40 +0100
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131:5825d48b27d1 132:1700239cab2e
1 /*******************************************************************************
2
3 copyright: Copyright (c) 2004 Kris Bell. All rights reserved
4
5 license: BSD style: $(LICENSE)
6
7 version: Apr 2004: Initial release
8 Dec 2006: Outback version
9 Apr 2007: Delegate revision
10
11 author: Kris
12
13 *******************************************************************************/
14
15 module tango.net.cluster.NetworkRegistry;
16
17 private import tango.core.Exception;
18
19 private import tango.net.cluster.model.IMessage;
20
21
22 /*******************************************************************************
23
24 Bare framework for registering and creating serializable objects.
25 Such objects are intended to be transported across a local network
26 and re-instantiated at some destination node.
27
28 Each IMessage exposes the means to write, or freeze, its content. An
29 IPickleFactory provides the means to create a new instance of itself
30 populated with thawed data. Frozen objects are uniquely identified
31 by a guid exposed via the interface. Responsibility of maintaining
32 uniqueness across said identifiers lies in the hands of the developer.
33
34 *******************************************************************************/
35
36 class NetworkRegistry
37 {
38 private IMessage[char[]] registry;
39
40 public static NetworkRegistry shared;
41
42 /***********************************************************************
43
44
45 ***********************************************************************/
46
47 static this ()
48 {
49 shared = new NetworkRegistry;
50 }
51
52 /***********************************************************************
53
54
55 ***********************************************************************/
56
57 this (typeof(registry) registry = null)
58 {
59 this.registry = registry;
60 }
61
62 /***********************************************************************
63
64 Synchronized Factory lookup of the guid
65
66 ***********************************************************************/
67
68 final synchronized IMessage lookup (char[] guid)
69 {
70 auto p = guid in registry;
71 if (p is null)
72 error ("Registry.thaw :: attempt to reify via unregistered guid: ", guid);
73
74 return *p;
75 }
76
77 /***********************************************************************
78
79 Add the provided Factory to the registry. Note that one
80 cannot change a registration once it is placed. Neither
81 can one remove registered item. This is done to avoid
82 issues when trying to synchronize servers across
83 a farm, which may still have live instances of "old"
84 objects waiting to be passed around the cluster. New
85 versions of an object should be given a distinct guid
86 from the prior version; appending an incremental number
87 may well be sufficient for your needs.
88
89 ***********************************************************************/
90
91 final synchronized void enroll (IMessage target)
92 {
93 auto guid = target.toString;
94
95 if (guid in registry)
96 error ("Registry.enroll :: attempt to re-register guid: ", guid);
97
98 registry[guid] = target;
99 }
100
101 /***********************************************************************
102
103 Serialize an Object. Objects are written in Network-order,
104 and are prefixed by the guid exposed via the IMessage
105 interface. This guid is used to identify the appropriate
106 factory when reconstructing the instance.
107
108 ***********************************************************************/
109
110 final void freeze (IWriter output, IMessage target)
111 {
112 output (target.toString);
113 target.write (output);
114 }
115
116 /***********************************************************************
117
118 Create a new instance of a registered class from the content
119 made available via the given reader. The factory is located
120 using the provided guid, which must match an enrolled factory.
121
122 Note that only the factory lookup is synchronized, and not
123 the instance construction itself. This is intentional, and
124 limits how long the calling thread is stalled
125
126 ***********************************************************************/
127
128 final IMessage thaw (IReader input, IMessage host = null)
129 {
130 char[] guid;
131
132 input (guid);
133
134 if (host is null)
135 host = lookup (guid);
136 else
137 if (guid != host.toString)
138 error ("Registry.thaw :: attempt to reify into a mismatched host: ", guid);
139
140 host.read (input);
141 return host;
142 }
143
144 /***********************************************************************
145
146 Duplicate the registry
147
148 ***********************************************************************/
149
150 final NetworkRegistry dup ()
151 {
152 typeof(registry) u;
153
154 foreach (k, v; registry)
155 u[k] = v.clone;
156 return new NetworkRegistry (u);
157 }
158
159 /***********************************************************************
160
161 ***********************************************************************/
162
163 private static void error (char[] msg, char[] guid)
164 {
165 throw new RegistryException (msg ~ guid);
166 }
167 }
168
169
170