bdburiuniqfilter.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> <em>     * @param env Environment to use.</em>
<a name="150" href="#150">150</a> <em>     * @throws DatabaseException</em>
<a name="151" href="#151">151</a> <em>     */</em>
<a name="152" href="#152">152</a>     <strong>protected</strong> <strong>void</strong> initialize(Environment env) throws DatabaseException {
<a name="153" href="#153">153</a>         DatabaseConfig dbConfig = <strong>new</strong> DatabaseConfig();
<a name="154" href="#154">154</a>         dbConfig.setAllowCreate(<strong>true</strong>);
<a name="155" href="#155">155</a>         <strong>try</strong> {
<a name="156" href="#156">156</a>             env.truncateDatabase(<strong>null</strong>, DB_NAME, false);
<a name="157" href="#157">157</a>         } <strong>catch</strong> (DatabaseNotFoundException e) {
<a name="158" href="#158">158</a>             <em class="comment">// Ignored</em>
<a name="159" href="#159">159</a>         }
<a name="160" href="#160">160</a>         open(env, dbConfig);
<a name="161" href="#161">161</a>     }
<a name="162" href="#162">162</a>     
<a name="163" href="#163">163</a>     <em>/**<em>*</em></em>
<a name="164" href="#164">164</a> <em>     * Call after deserializing an instance of this class.  Will open the</em>
<a name="165" href="#165">165</a> <em>     * already seen in passed environment.</em>
<a name="166" href="#166">166</a> <em>     * @param env DB Environment to use.</em>
<a name="167" href="#167">167</a> <em>     * @throws DatabaseException</em>
<a name="168" href="#168">168</a> <em>     */</em>
<a name="169" href="#169">169</a>     <strong>public</strong> <strong>void</strong> reopen(<strong>final</strong> Environment env)
<a name="170" href="#170">170</a>     throws DatabaseException {
<a name="171" href="#171">171</a>         open(env, <strong>null</strong>);
<a name="172" href="#172">172</a>     }
<a name="173" href="#173">173</a>     
<a name="174" href="#174">174</a>     <strong>protected</strong> <strong>void</strong> open(<strong>final</strong> Environment env, <strong>final</strong> DatabaseConfig dbConfig)
<a name="175" href="#175">175</a>     throws DatabaseException {
<a name="176" href="#176">176</a>         <strong>this</strong>.alreadySeen = env.openDatabase(<strong>null</strong>, DB_NAME, dbConfig);
<a name="177" href="#177">177</a>         <strong>this</strong>.value = <strong>new</strong> DatabaseEntry(<span class="string">""</span>.getBytes());
<a name="178" href="#178">178</a>     }
<a name="179" href="#179">179</a>     
<a name="180" href="#180">180</a>     <strong>public</strong> <strong>synchronized</strong> <strong>void</strong> close() {
<a name="181" href="#181">181</a>         Environment env = <strong>null</strong>;
<a name="182" href="#182">182</a>         <strong>if</strong> (<strong>this</strong>.alreadySeen != <strong>null</strong>) {
<a name="183" href="#183">183</a>         	<strong>try</strong> {
<a name="184" href="#184">184</a>                 env = <strong>this</strong>.alreadySeen.getEnvironment();
<a name="185" href="#185">185</a>                 <strong>if</strong> (logger.isLoggable(Level.INFO)) {
<a name="186" href="#186">186</a>                     logger.info(<span class="string">"Count of alreadyseen on close "</span> +
<a name="187" href="#187">187</a>                         Long.toString(count));
<a name="188" href="#188">188</a>                 }
<a name="189" href="#189">189</a> 				<strong>this</strong>.alreadySeen.close();
<a name="190" href="#190">190</a> 			} <strong>catch</strong> (DatabaseException e) {
<a name="191" href="#191">191</a> 				logger.severe(e.getMessage());
<a name="192" href="#192">192</a> 			}
<a name="193" href="#193">193</a>             <strong>this</strong>.alreadySeen = <strong>null</strong>;
<a name="194" href="#194">194</a>         }
<a name="195" href="#195">195</a>         <strong>if</strong> (env != <strong>null</strong> &amp;&amp; createdEnvironment) {
<a name="196" href="#196">196</a>             <strong>try</strong> {
<a name="197" href="#197">197</a> 				<em class="comment">// This sync flushes whats in RAM.  Its expensive operation.</em>
<a name="198" href="#198">198</a> 				<em class="comment">// Without, data can be lost.  Not for transactional operation.</em>
<a name="199" href="#199">199</a> 				env.sync();
<a name="200" href="#200">200</a> 				env.close();
<a name="201" href="#201">201</a> 			} <strong>catch</strong> (DatabaseException e) {
<a name="202" href="#202">202</a> 				logger.severe(e.getMessage());
<a name="203" href="#203">203</a> 			}
<a name="204" href="#204">204</a>         }
<a name="205" href="#205">205</a>     }
<a name="206" href="#206">206</a>     
<a name="207" href="#207">207</a>     <strong>public</strong> <strong>synchronized</strong> <strong>long</strong> getCacheMisses() throws DatabaseException {
<a name="208" href="#208">208</a>         <strong>long</strong> cacheMiss = <strong>this</strong>.alreadySeen.getEnvironment().
<a name="209" href="#209">209</a>             getStats(<strong>null</strong>).getNCacheMiss();
<a name="210" href="#210">210</a>         <strong>this</strong>.lastCacheMissDiff = cacheMiss - <strong>this</strong>.lastCacheMiss;
<a name="211" href="#211">211</a>         <strong>this</strong>.lastCacheMiss = cacheMiss;
<a name="212" href="#212">212</a>         <strong>return</strong> <strong>this</strong>.lastCacheMiss;
<a name="213" href="#213">213</a>     }
<a name="214" href="#214">214</a>     
<a name="215" href="#215">215</a>     <strong>public</strong> <strong>long</strong> getLastCacheMissDiff() {
<a name="216" href="#216">216</a>         <strong>return</strong> <strong>this</strong>.lastCacheMissDiff;
<a name="217" href="#217">217</a>     }
<a name="218" href="#218">218</a>     
<a name="219" href="#219">219</a>     <em>/**<em>*</em></em>
<a name="220" href="#220">220</a> <em>     * Create fingerprint.</em>
<a name="221" href="#221">221</a> <em>     * Pubic access so test code can access createKey.</em>
<a name="222" href="#222">222</a> <em>     * @param uri URI to fingerprint.</em>
<a name="223" href="#223">223</a> <em>     * @return Fingerprint of passed &lt;code>url&lt;/code>.</em>
<a name="224" href="#224">224</a> <em>     */</em>
<a name="225" href="#225">225</a>     <strong>public</strong> <strong>static</strong> <strong>long</strong> createKey(CharSequence uri) {
<a name="226" href="#226">226</a>         String url = uri.toString();
<a name="227" href="#227">227</a>         <strong>int</strong> index = url.indexOf(COLON_SLASH_SLASH);
<a name="228" href="#228">228</a>         <strong>if</strong> (index > 0) {
<a name="229" href="#229">229</a>             index = url.indexOf('/', index + COLON_SLASH_SLASH.length());
<a name="230" href="#230">230</a>         }
<a name="231" href="#231">231</a>         CharSequence hostPlusScheme = (index == -1)? url: url.subSequence(0, index);
<a name="232" href="#232">232</a>         <strong>long</strong> tmp = FPGenerator.std24.fp(hostPlusScheme);
<a name="233" href="#233">233</a>         <strong>return</strong> tmp | (FPGenerator.std40.fp(url) >>> 24);
<a name="234" href="#234">234</a>     }
<a name="235" href="#235">235</a> 
<a name="236" href="#236">236</a> 
<a name="237" href="#237">237</a> 
<a name="238" href="#238">238</a>     <strong>protected</strong> <strong>boolean</strong> setAdd(CharSequence uri) {
<a name="239" href="#239">239</a>         DatabaseEntry key = <strong>new</strong> DatabaseEntry();
<a name="240" href="#240">240</a>         LongBinding.longToEntry(createKey(uri), key);
<a name="241" href="#241">241</a>         <strong>long</strong> started = 0;
<a name="242" href="#242">242</a>         
<a name="243" href="#243">243</a>         OperationStatus status = <strong>null</strong>;
<a name="244" href="#244">244</a>         <strong>try</strong> {
<a name="245" href="#245">245</a>             <strong>if</strong> (logger.isLoggable(Level.INFO)) {
<a name="246" href="#246">246</a>                 started = System.currentTimeMillis();
<a name="247" href="#247">247</a>             }
<a name="248" href="#248">248</a>             status = alreadySeen.putNoOverwrite(<strong>null</strong>, key, value);
<a name="249" href="#249">249</a>             <strong>if</strong> (logger.isLoggable(Level.INFO)) {
<a name="250" href="#250">250</a>                 aggregatedLookupTime +=
<a name="251" href="#251">251</a>                     (System.currentTimeMillis() - started);
<a name="252" href="#252">252</a>             }
<a name="253" href="#253">253</a>         } <strong>catch</strong> (DatabaseException e) {
<a name="254" href="#254">254</a>             logger.severe(e.getMessage());
<a name="255" href="#255">255</a>         }
<a name="256" href="#256">256</a>         <strong>if</strong> (status == OperationStatus.SUCCESS) {
<a name="257" href="#257">257</a>             count++;
<a name="258" href="#258">258</a>             <strong>if</strong> (logger.isLoggable(Level.INFO)) {
<a name="259" href="#259">259</a>                 <strong>final</strong> <strong>int</strong> logAt = 10000;
<a name="260" href="#260">260</a>                 <strong>if</strong> (count > 0 &amp;&amp; ((count % logAt) == 0)) {
<a name="261" href="#261">261</a>                     logger.info(<span class="string">"Average lookup "</span> +
<a name="262" href="#262">262</a>                         (aggregatedLookupTime / logAt) + <span class="string">"ms."</span>);
<a name="263" href="#263">263</a>                     aggregatedLookupTime = 0;
<a name="264" href="#264">264</a>                 }
<a name="265" href="#265">265</a>             }
<a name="266" href="#266">266</a>         }
<a name="267" href="#267">267</a>         <strong>if</strong>(status == OperationStatus.KEYEXIST) {
<a name="268" href="#268">268</a>             <strong>return</strong> false; <em class="comment">// not added</em>
<a name="269" href="#269">269</a>         } <strong>else</strong> {
<a name="270" href="#270">270</a>             <strong>return</strong> <strong>true</strong>;
<a name="271" href="#271">271</a>         }
<a name="272" href="#272">272</a>     }
<a name="273" href="#273">273</a> 
<a name="274" href="#274">274</a>     <strong>protected</strong> <strong>long</strong> setCount() {
<a name="275" href="#275">275</a>         <strong>return</strong> count;
<a name="276" href="#276">276</a>     }
<a name="277" href="#277">277</a> 
<a name="278" href="#278">278</a>     <strong>protected</strong> <strong>boolean</strong> setRemove(CharSequence uri) {
<a name="279" href="#279">279</a>         DatabaseEntry key = <strong>new</strong> DatabaseEntry();
<a name="280" href="#280">280</a>         LongBinding.longToEntry(createKey(uri), key);
<a name="281" href="#281">281</a>             OperationStatus status = <strong>null</strong>;
<a name="282" href="#282">282</a>         <strong>try</strong> {
<a name="283" href="#283">283</a>             status = alreadySeen.delete(<strong>null</strong>, key);
<a name="284" href="#284">284</a>         } <strong>catch</strong> (DatabaseException e) {
<a name="285" href="#285">285</a>             logger.severe(e.getMessage());
<a name="286" href="#286">286</a>         }
<a name="287" href="#287">287</a>         <strong>if</strong> (status == OperationStatus.SUCCESS) {
<a name="288" href="#288">288</a>             count--;
<a name="289" href="#289">289</a>             <strong>return</strong> <strong>true</strong>; <em class="comment">// removed</em>
<a name="290" href="#290">290</a>         } <strong>else</strong> {
<a name="291" href="#291">291</a>             <strong>return</strong> false; <em class="comment">// not present</em>
<a name="292" href="#292">292</a>         }
<a name="293" href="#293">293</a>     }
<a name="294" href="#294">294</a> 
<a name="295" href="#295">295</a>     <strong>public</strong> <strong>long</strong> flush() {
<a name="296" href="#296">296</a>     	    <em class="comment">// We always write but this might be place to do the sync</em>
<a name="297" href="#297">297</a>         <em class="comment">// when checkpointing?  TODO.</em>
<a name="298" href="#298">298</a>         <strong>return</strong> 0;
<a name="299" href="#299">299</a>     }
<a name="300" href="#300">300</a> }
</pre>
<hr/><div id="footer">This page was automatically generated by <a href="http://maven.apache.org/">Maven</a></div></body>
</html>