cachedbdbmap.html

用JAVA编写的,在做实验的时候留下来的,本来想删的,但是传上来,大家分享吧

<a name="149" href="#149">149</a>     }
<a name="150" href="#150">150</a>     
<a name="151" href="#151">151</a>     <em>/**<em>*</em></em>
<a name="152" href="#152">152</a> <em>     * Shudown default constructor.</em>
<a name="153" href="#153">153</a> <em>     */</em>
<a name="154" href="#154">154</a>     <strong>private</strong> <a href="../../../org/archive/util/CachedBdbMap.html">CachedBdbMap</a>() {
<a name="155" href="#155">155</a>         <strong>super</strong>();
<a name="156" href="#156">156</a>     }
<a name="157" href="#157">157</a>     
<a name="158" href="#158">158</a>     <em>/**<em>*</em></em>
<a name="159" href="#159">159</a> <em>     * Constructor.</em>
<a name="160" href="#160">160</a> <em>     * </em>
<a name="161" href="#161">161</a> <em>     * You must call</em>
<a name="162" href="#162">162</a> <em>     * {@link #initialize(Environment, Class, Class, StoredClassCatalog)}</em>
<a name="163" href="#163">163</a> <em>     * to finish construction. Construction is two-stepped to support</em>
<a name="164" href="#164">164</a> <em>     * reconnecting a deserialized CachedBdbMap with its backing bdbje</em>
<a name="165" href="#165">165</a> <em>     * database.</em>
<a name="166" href="#166">166</a> <em>     * </em>
<a name="167" href="#167">167</a> <em>     * @param dbName Name of the backing db this instance should use.</em>
<a name="168" href="#168">168</a> <em>     */</em>
<a name="169" href="#169">169</a>     <strong>public</strong> <a href="../../../org/archive/util/CachedBdbMap.html">CachedBdbMap</a>(<strong>final</strong> String dbName) {
<a name="170" href="#170">170</a>         <strong>this</strong>();
<a name="171" href="#171">171</a>         <strong>this</strong>.dbName = dbName;
<a name="172" href="#172">172</a>     }
<a name="173" href="#173">173</a> 
<a name="174" href="#174">174</a>     <em>/**<em>*</em></em>
<a name="175" href="#175">175</a> <em>     * A constructor for creating a new CachedBdbMap.</em>
<a name="176" href="#176">176</a> <em>     * </em>
<a name="177" href="#177">177</a> <em>     * Even though the put and get methods conforms to the Collections interface</em>
<a name="178" href="#178">178</a> <em>     * taking any object as key or value, you have to submit the class of the</em>
<a name="179" href="#179">179</a> <em>     * allowed key and value objects here and will get an exception if you try</em>
<a name="180" href="#180">180</a> <em>     * to put anything else in the map.</em>
<a name="181" href="#181">181</a> <em>     * </em>
<a name="182" href="#182">182</a> <em>     * &lt;p>This constructor internally calls</em>
<a name="183" href="#183">183</a> <em>     * {@link #initialize(Environment, Class, Class, StoredClassCatalog)}.</em>
<a name="184" href="#184">184</a> <em>     * Do not call initialize if you use this constructor.</em>
<a name="185" href="#185">185</a> <em>     * </em>
<a name="186" href="#186">186</a> <em>     * @param dbDir The directory where the database will be created.</em>
<a name="187" href="#187">187</a> <em>     * @param dbName The name of the database to back this map by.</em>
<a name="188" href="#188">188</a> <em>     * @param keyClass The class of the objects allowed as keys.</em>
<a name="189" href="#189">189</a> <em>     * @param valueClass The class of the objects allowed as values.</em>
<a name="190" href="#190">190</a> <em>     * </em>
<a name="191" href="#191">191</a> <em>     * @throws DatabaseException is thrown if the underlying BDB JE database</em>
<a name="192" href="#192">192</a> <em>     *             throws an exception.</em>
<a name="193" href="#193">193</a> <em>     */</em>
<a name="194" href="#194">194</a>     <strong>public</strong> <a href="../../../org/archive/util/CachedBdbMap.html">CachedBdbMap</a>(<strong>final</strong> File dbDir, <strong>final</strong> String dbName,
<a name="195" href="#195">195</a>             <strong>final</strong> Class keyClass, <strong>final</strong> Class valueClass)
<a name="196" href="#196">196</a>     throws DatabaseException {
<a name="197" href="#197">197</a>         <strong>this</strong>(dbName);
<a name="198" href="#198">198</a>         <strong>this</strong>.dbEnvironment = getDbEnvironment(dbDir);
<a name="199" href="#199">199</a>         <strong>this</strong>.dbEnvironment.openDbCount++;
<a name="200" href="#200">200</a>         initialize(dbEnvironment.environment, keyClass, valueClass,
<a name="201" href="#201">201</a>             dbEnvironment.classCatalog);
<a name="202" href="#202">202</a>         <strong>if</strong> (logger.isLoggable(Level.INFO)) {
<a name="203" href="#203">203</a>             <em class="comment">// Write out the bdb configuration.</em>
<a name="204" href="#204">204</a>             EnvironmentConfig cfg = <strong>this</strong>.dbEnvironment.environment.getConfig();
<a name="205" href="#205">205</a>             logger.info(<span class="string">"BdbConfiguration: Cache percentage "</span>  +
<a name="206" href="#206">206</a>                 cfg.getCachePercent() + <span class="string">", cache size "</span> + cfg.getCacheSize() +
<a name="207" href="#207">207</a>                 <span class="string">", Map size: "</span> + size());
<a name="208" href="#208">208</a>         }
<a name="209" href="#209">209</a>     }
<a name="210" href="#210">210</a>     
<a name="211" href="#211">211</a>     <em>/**<em>*</em></em>
<a name="212" href="#212">212</a> <em>     * Call this method when you have an instance when you used the</em>
<a name="213" href="#213">213</a> <em>     * default constructor or when you have a deserialized instance that you</em>
<a name="214" href="#214">214</a> <em>     * want to reconnect with an extant bdbje environment.  Do not</em>
<a name="215" href="#215">215</a> <em>     * call this method if you used the</em>
<a name="216" href="#216">216</a> <em>     * {@link #CachedBdbMap(File, String, Class, Class)} constructor.</em>
<a name="217" href="#217">217</a> <em>     * @param env</em>
<a name="218" href="#218">218</a> <em>     * @param keyClass</em>
<a name="219" href="#219">219</a> <em>     * @param valueClass</em>
<a name="220" href="#220">220</a> <em>     * @param classCatalog</em>
<a name="221" href="#221">221</a> <em>     * @throws DatabaseException</em>
<a name="222" href="#222">222</a> <em>     */</em>
<a name="223" href="#223">223</a>     <strong>public</strong> <strong>synchronized</strong> <strong>void</strong> initialize(<strong>final</strong> Environment env, <strong>final</strong> Class keyClass,
<a name="224" href="#224">224</a>             <strong>final</strong> Class valueClass, <strong>final</strong> StoredClassCatalog classCatalog)
<a name="225" href="#225">225</a>     throws DatabaseException {
<a name="226" href="#226">226</a>         initializeInstance();
<a name="227" href="#227">227</a>         <strong>this</strong>.db = openDatabase(env, <strong>this</strong>.dbName);
<a name="228" href="#228">228</a>         <strong>this</strong>.diskMap = createDiskMap(<strong>this</strong>.db, classCatalog, keyClass,
<a name="229" href="#229">229</a>             valueClass);
<a name="230" href="#230">230</a>     }
<a name="231" href="#231">231</a>     
<a name="232" href="#232">232</a>     <em>/**<em>*</em></em>
<a name="233" href="#233">233</a> <em>     * Do any instance setup.</em>
<a name="234" href="#234">234</a> <em>     * This method is used by constructors and when deserializing an instance.</em>
<a name="235" href="#235">235</a> <em>     */</em>
<a name="236" href="#236">236</a>     <strong>protected</strong> <strong>void</strong> initializeInstance() {
<a name="237" href="#237">237</a>         <strong>this</strong>.memMap = <strong>new</strong> HashMap();
<a name="238" href="#238">238</a>         <strong>this</strong>.refQueue = <strong>new</strong> ReferenceQueue();
<a name="239" href="#239">239</a>     }
<a name="240" href="#240">240</a>     
<a name="241" href="#241">241</a>     <strong>protected</strong> StoredSortedMap createDiskMap(Database database,
<a name="242" href="#242">242</a>             StoredClassCatalog classCatalog, Class keyClass, Class valueClass) {
<a name="243" href="#243">243</a>         EntryBinding keyBinding = TupleBinding.getPrimitiveBinding(keyClass);
<a name="244" href="#244">244</a>         <strong>if</strong>(keyBinding == <strong>null</strong>) {
<a name="245" href="#245">245</a>             keyBinding = <strong>new</strong> SerialBinding(classCatalog, keyClass);
<a name="246" href="#246">246</a>         }
<a name="247" href="#247">247</a>         EntryBinding valueBinding = TupleBinding.getPrimitiveBinding(valueClass);
<a name="248" href="#248">248</a>         <strong>if</strong>(valueBinding == <strong>null</strong>) {
<a name="249" href="#249">249</a>             valueBinding = <strong>new</strong> SerialBinding(classCatalog, valueClass);
<a name="250" href="#250">250</a>         }
<a name="251" href="#251">251</a>         <strong>return</strong> <strong>new</strong> StoredSortedMap(database, keyBinding, valueBinding, <strong>true</strong>);
<a name="252" href="#252">252</a>     }
<a name="253" href="#253">253</a> 
<a name="254" href="#254">254</a>     <em>/**<em>*</em></em>
<a name="255" href="#255">255</a> <em>     * Get the database environment for a physical directory where data will be</em>
<a name="256" href="#256">256</a> <em>     * stored.</em>
<a name="257" href="#257">257</a> <em>     * &lt;p></em>
<a name="258" href="#258">258</a> <em>     * If the environment already exist it will be reused, else a new one will</em>
<a name="259" href="#259">259</a> <em>     * be created.</em>
<a name="260" href="#260">260</a> <em>     * </em>
<a name="261" href="#261">261</a> <em>     * @param dbDir The directory where BDB JE data will be stored.</em>
<a name="262" href="#262">262</a> <em>     * @return a datastructure containing the environment and a default database</em>
<a name="263" href="#263">263</a> <em>     *         for storing class definitions.</em>
<a name="264" href="#264">264</a> <em>     */</em>
<a name="265" href="#265">265</a>     <strong>private</strong> DbEnvironmentEntry getDbEnvironment(File dbDir) {
<a name="266" href="#266">266</a>         <strong>if</strong> (dbEnvironmentMap.containsKey(dbDir.getAbsolutePath())) {
<a name="267" href="#267">267</a>             <strong>return</strong> (DbEnvironmentEntry) dbEnvironmentMap.get(dbDir
<a name="268" href="#268">268</a>                     .getAbsolutePath());
<a name="269" href="#269">269</a>         }
<a name="270" href="#270">270</a>         EnvironmentConfig envConfig = <strong>new</strong> EnvironmentConfig();
<a name="271" href="#271">271</a>         envConfig.setAllowCreate(<strong>true</strong>);
<a name="272" href="#272">272</a>         envConfig.setTransactional(false);
<a name="273" href="#273">273</a>         
<a name="274" href="#274">274</a>         <em class="comment">// We're doing the caching ourselves so setting these at the lowest</em>
<a name="275" href="#275">275</a>         <em class="comment">// possible level.</em>
<a name="276" href="#276">276</a>         envConfig.setCachePercent(1);
<a name="277" href="#277">277</a>         DbEnvironmentEntry env = <strong>new</strong> DbEnvironmentEntry();
<a name="278" href="#278">278</a>         <strong>try</strong> {
<a name="279" href="#279">279</a>             env.environment = <strong>new</strong> Environment(dbDir, envConfig);
<a name="280" href="#280">280</a>             env.dbDir = dbDir;
<a name="281" href="#281">281</a>             dbEnvironmentMap.put(dbDir.getAbsolutePath(), env);
<a name="282" href="#282">282</a>             
<a name="283" href="#283">283</a>             DatabaseConfig dbConfig = <strong>new</strong> DatabaseConfig();
<a name="284" href="#284">284</a>             dbConfig.setTransactional(false);
<a name="285" href="#285">285</a>             dbConfig.setAllowCreate(<strong>true</strong>);
<a name="286" href="#286">286</a>             
<a name="287" href="#287">287</a>             Database catalogDb = env.environment.openDatabase(<strong>null</strong>,
<a name="288" href="#288">288</a>                     CLASS_CATALOG, dbConfig);
<a name="289" href="#289">289</a>             
<a name="290" href="#290">290</a>             env.classCatalog = <strong>new</strong> StoredClassCatalog(catalogDb);
<a name="291" href="#291">291</a>         } <strong>catch</strong> (DatabaseException e) {
<a name="292" href="#292">292</a>             e.printStackTrace();
<a name="293" href="#293">293</a>             <em class="comment">//throw new FatalConfigurationException(e.getMessage());</em>
<a name="294" href="#294">294</a>         }
<a name="295" href="#295">295</a>         <strong>return</strong> env;
<a name="296" href="#296">296</a>     }
<a name="297" href="#297">297</a> 
<a name="298" href="#298">298</a>     <strong>protected</strong> Database openDatabase(<strong>final</strong> Environment environment,
<a name="299" href="#299">299</a>             <strong>final</strong> String dbName) throws DatabaseException {
<a name="300" href="#300">300</a>         DatabaseConfig dbConfig = <strong>new</strong> DatabaseConfig();
<a name="301" href="#301">301</a>         dbConfig.setTransactional(false);
<a name="302" href="#302">302</a>         dbConfig.setAllowCreate(<strong>true</strong>);
<a name="303" href="#303">303</a>         <strong>return</strong> environment.openDatabase(<strong>null</strong>, dbName, dbConfig);
<a name="304" href="#304">304</a>     }
<a name="305" href="#305">305</a>