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comparison tango/tango/net/cluster/CacheInvalidator.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: July 2004: Initial release
8
9 author: Kris
10
11 *******************************************************************************/
12
13 module tango.net.cluster.CacheInvalidator;
14
15 package import tango.net.cluster.NetworkClient;
16
17 private import tango.net.cluster.NetworkMessage;
18
19 /*******************************************************************************
20
21 Utility class to invalidate specific cache entries across a
22 network. Any active CacheInvalidatee objects listening upon
23 the channel specified for this class will "wake up" whenever
24 the invalidate() method is invoked.
25
26 *******************************************************************************/
27
28 class CacheInvalidator : NetworkClient
29 {
30 private InvalidatorPayload filter;
31
32 /***********************************************************************
33
34 Construct an invalidator on the specified channel. Only
35 those CacheInvalidatee instances configured for the same
36 channel will be listening to this invalidator.
37
38 ***********************************************************************/
39
40 this (ICluster cluster, char[] channel)
41 {
42 assert (channel.length);
43 super (cluster, channel);
44
45 // this is what we'll send as an invalidation notification ...
46 this.filter = new InvalidatorPayload;
47 }
48
49 /***********************************************************************
50
51 Invalidate all network cache instances on this channel
52 using the specified key. When 'timeLimit' is specified,
53 only those cache entries with a time lesser or equal to
54 that specified will be removed. This is often useful if
55 you wish to avoid invalidating a cache (local or remote)
56 that has just been updated; simply pass the time value
57 of the 'old' IMessage as the argument.
58
59 Note that this is asynchronous! An invalidation is just
60 a request to remove the item within a short time period.
61 If you need the entry removed synchronously, you should
62 use the NetworkCache extract() method instead.
63
64 ***********************************************************************/
65
66 void invalidate (char[] key, Time timeLimit = Time.max)
67 {
68 assert (key.length);
69 filter.key (key);
70 filter.time (timeLimit);
71
72 // broadcast a message across the cluster
73 channel.broadcast (filter);
74 }
75 }
76
77
78 /*******************************************************************************
79
80 *******************************************************************************/
81
82 private class InvalidatorPayload : NetworkMessage
83 {
84 private char[] key_;
85
86 /***********************************************************************
87
88 ***********************************************************************/
89
90 char[] key ()
91 {
92 return key_;
93 }
94
95 /***********************************************************************
96
97 ***********************************************************************/
98
99 void key (char[] key)
100 {
101 assert (key.length);
102 key_ = key;
103 }
104
105 /***********************************************************************
106
107 Read our attributes, after telling our superclass to do
108 likewise. The order of this is important with respect to
109 inheritance, such that a subclass and superclass may be
110 populated in isolation where appropriate.
111
112 Note that we slice our text attribute, rather than copying
113 it. Since this class is temporal we can forego allocation
114 of memory, and just map it directly from the input buffer.
115
116 ***********************************************************************/
117
118 override void read (IReader input)
119 {
120 super.read (input);
121 input (key_);
122 }
123
124 /***********************************************************************
125
126 ***********************************************************************/
127
128 override void write (IWriter output)
129 {
130 super.write (output);
131 output (key_);
132 }
133 }
134