00001 /******************************************************************************* 00002 00003 @file PlainCache.d 00004 00005 Copyright (C) 2004 Kris Bell 00006 00007 This software is provided 'as-is', without any express or implied 00008 warranty. In no event will the authors be held liable for damages 00009 of any kind arising from the use of this software. 00010 00011 Permission is hereby granted to anyone to use this software for any 00012 purpose, including commercial applications, and to alter it and/or 00013 redistribute it freely, subject to the following restrictions: 00014 00015 1. The origin of this software must not be misrepresented; you must 00016 not claim that you wrote the original software. If you use this 00017 software in a product, an acknowledgment within documentation of 00018 said product would be appreciated but is not required. 00019 00020 2. Altered source versions must be plainly marked as such, and must 00021 not be misrepresented as being the original software. 00022 00023 3. This notice may not be removed or altered from any distribution 00024 of the source. 00025 00026 00027 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 00028 00029 00030 @version Initial version, April 2004 00031 @author Kris 00032 00033 00034 *******************************************************************************/ 00035 00036 module mango.cache.PlainCache; 00037 00038 public import mango.cache.HashMap; 00039 00040 public import mango.cache.model.ICache, 00041 mango.cache.model.IPayload; 00042 00043 /****************************************************************************** 00044 00045 A base-class for the cache framework, using a thread-aware hash map 00046 to contain the cache entries. Cache entries must be instances of the 00047 IPayload interface; this allows them to be moved around the network 00048 or serialized onto some external medium. 00049 00050 ******************************************************************************/ 00051 00052 class PlainCache : IMutableCache 00053 { 00054 private HashMap map; 00055 00056 /********************************************************************** 00057 00058 Construct a basic cache with the specified number of 00059 preallocated entries. The concurrency level indicates 00060 approximately how many threads will content for write 00061 access at one time. 00062 00063 **********************************************************************/ 00064 00065 this (uint capacity = 101, uint concurrency = 16) 00066 { 00067 map = new HashMap (capacity, 0.75, concurrency); 00068 } 00069 00070 /********************************************************************** 00071 00072 Get the cache entry identified by the given key 00073 00074 **********************************************************************/ 00075 00076 IPayload get (char[] key) 00077 { 00078 return cast (IPayload) map.get (key); 00079 } 00080 00081 /********************************************************************** 00082 00083 Place an entry into the cache and associate it with the 00084 provided key. Note that there can be only one entry for 00085 any particular key. If two keys entries are added with 00086 the same key, the second effectively overwrites the first. 00087 00088 Returns what it was given 00089 00090 **********************************************************************/ 00091 00092 IPayload put(char[] key, IPayload entry) 00093 { 00094 map.put (key, cast(Object) entry); 00095 return entry; 00096 } 00097 00098 /********************************************************************** 00099 00100 Remove (and return) the cache entry associated with the 00101 provided key. Returns null if there is no such entry. 00102 00103 **********************************************************************/ 00104 00105 IPayload extract (char[] key) 00106 { 00107 return cast(IPayload) map.remove (key); 00108 } 00109 00110 /********************************************************************** 00111 00112 Remove (and return) the cache entry associated with the 00113 provided key. Returns null if there is no such entry. 00114 00115 **********************************************************************/ 00116 00117 IPayload extract (char[] key, ulong timeLimit) 00118 { 00119 IPayload e = cast(IPayload) map.get (key); 00120 00121 if (e) 00122 { 00123 // ignore if existing entry is newer 00124 if (e.getTime > timeLimit) 00125 return null; 00126 00127 // remove the entry from array, and return it 00128 map.remove (key); 00129 } 00130 return e; 00131 } 00132 00133 /********************************************************************** 00134 00135 **********************************************************************/ 00136 00137 ICache bind (ICacheLoader loader) 00138 { 00139 class PlainLoader : ICache 00140 { 00141 IMutableCache cache; 00142 ICacheLoader loader; 00143 00144 /****************************************************** 00145 00146 ******************************************************/ 00147 00148 this (IMutableCache cache, ICacheLoader loader) 00149 { 00150 this.cache = cache; 00151 this.loader = loader; 00152 } 00153 00154 /****************************************************** 00155 00156 ******************************************************/ 00157 00158 IPayload get (char[] key) 00159 { 00160 long t; 00161 IPayload p = cache.get (key); 00162 00163 if (p) 00164 { 00165 if (loader.test (p)) 00166 return p; 00167 t = p.getTime (); 00168 } 00169 00170 p = loader.load (key, t); 00171 if (p) 00172 cache.put (key, p); 00173 return p; 00174 } 00175 } 00176 00177 return new PlainLoader (this, loader); 00178 } 00179 } 00180 00181