adaptiverevisitfrontier.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="397" href="#397">397</a>             <em class="comment">// And it needs rapid scheduling.</em>
<a name="398" href="#398">398</a>             curi.setSchedulingDirective(CandidateURI.MEDIUM);
<a name="399" href="#399">399</a>         }
<a name="400" href="#400">400</a>         
<a name="401" href="#401">401</a>         <em class="comment">// Optionally preferencing embeds up to MEDIUM</em>
<a name="402" href="#402">402</a>         <strong>int</strong> prefHops = ((Integer) getUncheckedAttribute(curi,
<a name="403" href="#403">403</a>                 ATTR_PREFERENCE_EMBED_HOPS)).intValue();
<a name="404" href="#404">404</a>         <strong>boolean</strong> prefEmbed = false;
<a name="405" href="#405">405</a>         <strong>if</strong> (prefHops > 0) {
<a name="406" href="#406">406</a>             <strong>int</strong> embedHops = curi.getTransHops();
<a name="407" href="#407">407</a>             <strong>if</strong> (embedHops > 0 &amp;&amp; embedHops &lt;= prefHops
<a name="408" href="#408">408</a>                     &amp;&amp; curi.getSchedulingDirective() == CandidateURI.NORMAL) {
<a name="409" href="#409">409</a>                 <em class="comment">// number of embed hops falls within the preferenced range, and</em>
<a name="410" href="#410">410</a>                 <em class="comment">// uri is not already MEDIUM -- so promote it</em>
<a name="411" href="#411">411</a>                 curi.setSchedulingDirective(CandidateURI.MEDIUM);
<a name="412" href="#412">412</a>                 prefEmbed = <strong>true</strong>;
<a name="413" href="#413">413</a>             }
<a name="414" href="#414">414</a>         }
<a name="415" href="#415">415</a> 
<a name="416" href="#416">416</a>         <em class="comment">// Finally, allow curi to be fetched right now </em>
<a name="417" href="#417">417</a>         <em class="comment">// (while not overriding overdue items)</em>
<a name="418" href="#418">418</a>         curi.putLong(A_TIME_OF_NEXT_PROCESSING,
<a name="419" href="#419">419</a>                 System.currentTimeMillis());
<a name="420" href="#420">420</a>         
<a name="421" href="#421">421</a>         <strong>try</strong> {
<a name="422" href="#422">422</a>             logger.finest(<span class="string">"scheduling "</span> + curi.toString());
<a name="423" href="#423">423</a>             <a href="../../../../org/archive/crawler/frontier/AdaptiveRevisitHostQueue.html">AdaptiveRevisitHostQueue</a> hq = getHQ(curi);
<a name="424" href="#424">424</a>             hq.add(curi,prefEmbed);
<a name="425" href="#425">425</a>         } <strong>catch</strong> (IOException e) {
<a name="426" href="#426">426</a>             <em class="comment">// TODO Handle IOExceptions</em>
<a name="427" href="#427">427</a>             e.printStackTrace();
<a name="428" href="#428">428</a>         }
<a name="429" href="#429">429</a>         
<a name="430" href="#430">430</a>     }
<a name="431" href="#431">431</a> 
<a name="432" href="#432">432</a>     <em>/**<em>*</em></em>
<a name="433" href="#433">433</a> <em>     * Get the AdaptiveRevisitHostQueue for the given CrawlURI, creating</em>
<a name="434" href="#434">434</a> <em>     * it if necessary. </em>
<a name="435" href="#435">435</a> <em>     * </em>
<a name="436" href="#436">436</a> <em>     * @param curi CrawlURI for which to get a queue</em>
<a name="437" href="#437">437</a> <em>     * @return AdaptiveRevisitHostQueue for given CrawlURI</em>
<a name="438" href="#438">438</a> <em>     * @throws IOException</em>
<a name="439" href="#439">439</a> <em>     */</em>
<a name="440" href="#440">440</a>     <strong>protected</strong> <a href="../../../../org/archive/crawler/frontier/AdaptiveRevisitHostQueue.html">AdaptiveRevisitHostQueue</a> getHQ(<a href="../../../../org/archive/crawler/datamodel/CrawlURI.html">CrawlURI</a> curi) throws IOException {
<a name="441" href="#441">441</a>         <a href="../../../../org/archive/crawler/frontier/AdaptiveRevisitHostQueue.html">AdaptiveRevisitHostQueue</a> hq = hostQueues.getHQ(curi.getClassKey());
<a name="442" href="#442">442</a>         <strong>if</strong>(hq == <strong>null</strong>){
<a name="443" href="#443">443</a>             <em class="comment">// Need to create it.</em>
<a name="444" href="#444">444</a>             <strong>int</strong> valence = DEFAULT_HOST_VALENCE.<strong>int</strong>Value();
<a name="445" href="#445">445</a>             <strong>try</strong> {
<a name="446" href="#446">446</a>                 valence = ((Integer)getAttribute(curi,ATTR_HOST_VALENCE)).intValue();
<a name="447" href="#447">447</a>             } <strong>catch</strong> (AttributeNotFoundException e2) {
<a name="448" href="#448">448</a>                 logger.severe(<span class="string">"Unable to load valence."</span>);
<a name="449" href="#449">449</a>             }
<a name="450" href="#450">450</a>             hq = hostQueues.createHQ(curi.getClassKey(),valence);
<a name="451" href="#451">451</a>         }
<a name="452" href="#452">452</a>         <strong>return</strong> hq;
<a name="453" href="#453">453</a>     }
<a name="454" href="#454">454</a> 
<a name="455" href="#455">455</a>     <strong>protected</strong> <strong>void</strong> batchSchedule(<a href="../../../../org/archive/crawler/datamodel/CandidateURI.html">CandidateURI</a> caUri) {
<a name="456" href="#456">456</a>         threadWaiting.getQueue().enqueue(caUri);
<a name="457" href="#457">457</a>     }
<a name="458" href="#458">458</a> 
<a name="459" href="#459">459</a>     <strong>protected</strong> <strong>void</strong> batchFlush() {
<a name="460" href="#460">460</a>         innerBatchFlush();
<a name="461" href="#461">461</a>     }
<a name="462" href="#462">462</a> 
<a name="463" href="#463">463</a>     <strong>private</strong> <strong>void</strong> innerBatchFlush() {
<a name="464" href="#464">464</a>         <a href="../../../../org/archive/queue/Queue.html">Queue</a> q = threadWaiting.getQueue();
<a name="465" href="#465">465</a>         <strong>while</strong>(!q.isEmpty()) {
<a name="466" href="#466">466</a>             <a href="../../../../org/archive/crawler/datamodel/CandidateURI.html">CandidateURI</a> caUri = (CandidateURI)q.dequeue();
<a name="467" href="#467">467</a>             <strong>if</strong>(alreadyIncluded != <strong>null</strong>){
<a name="468" href="#468">468</a>                 String cannon = canonicalize(caUri);
<a name="469" href="#469">469</a>                 System.out.println(<span class="string">"Cannon of "</span> + caUri + <span class="string">" is "</span> + cannon);
<a name="470" href="#470">470</a>                 <strong>if</strong> (caUri.forceFetch()) {
<a name="471" href="#471">471</a>                     alreadyIncluded.addForce(cannon, caUri);
<a name="472" href="#472">472</a>                 } <strong>else</strong> {
<a name="473" href="#473">473</a>                     alreadyIncluded.add(cannon, caUri);
<a name="474" href="#474">474</a>                 }
<a name="475" href="#475">475</a>             } <strong>else</strong> {
<a name="476" href="#476">476</a>                 innerSchedule(caUri);
<a name="477" href="#477">477</a>             }
<a name="478" href="#478">478</a>         }
<a name="479" href="#479">479</a>     }
<a name="480" href="#480">480</a>     
<a name="481" href="#481">481</a>     <em>/**<em>*</em></em>
<a name="482" href="#482">482</a> <em>     * @param curi</em>
<a name="483" href="#483">483</a> <em>     * @return the CrawlServer to be associated with this CrawlURI</em>
<a name="484" href="#484">484</a> <em>     */</em>
<a name="485" href="#485">485</a>     <strong>protected</strong> <a href="../../../../org/archive/crawler/datamodel/CrawlServer.html">CrawlServer</a> getServer(<a href="../../../../org/archive/crawler/datamodel/CrawlURI.html">CrawlURI</a> curi) {
<a name="486" href="#486">486</a>         <strong>return</strong> <strong>this</strong>.controller.getServerCache().getServerFor(curi);
<a name="487" href="#487">487</a>     }
<a name="488" href="#488">488</a> 
<a name="489" href="#489">489</a>     <em class="comment">/*<em class="comment"> (non-Javadoc)</em></em>
<a name="490" href="#490">490</a> <em class="comment">     * @see org.archive.crawler.framework.Frontier#next()</em>
<a name="491" href="#491">491</a> <em class="comment">     */</em>
<a name="492" href="#492">492</a>     <strong>public</strong> <strong>synchronized</strong> <a href="../../../../org/archive/crawler/datamodel/CrawlURI.html">CrawlURI</a> next() 
<a name="493" href="#493">493</a>             throws InterruptedException, <a href="../../../../org/archive/crawler/framework/exceptions/EndedException.html">EndedException</a> {
<a name="494" href="#494">494</a>         controller.checkFinish();
<a name="495" href="#495">495</a>         
<a name="496" href="#496">496</a>         <strong>while</strong>(shouldPause){
<a name="497" href="#497">497</a>             controller.toePaused();
<a name="498" href="#498">498</a>             wait();
<a name="499" href="#499">499</a>         }
<a name="500" href="#500">500</a>         
<a name="501" href="#501">501</a>         <strong>if</strong>(shouldTerminate){
<a name="502" href="#502">502</a>             <strong>throw</strong> <strong>new</strong> <a href="../../../../org/archive/crawler/framework/exceptions/EndedException.html">EndedException</a>(<span class="string">"terminated"</span>);
<a name="503" href="#503">503</a>         }
<a name="504" href="#504">504</a>         
<a name="505" href="#505">505</a>         <a href="../../../../org/archive/crawler/frontier/AdaptiveRevisitHostQueue.html">AdaptiveRevisitHostQueue</a> hq = hostQueues.getTopHQ();
<a name="506" href="#506">506</a>         
<a name="507" href="#507">507</a>         <strong>while</strong>(hq.getState() != AdaptiveRevisitHostQueue.HQSTATE_READY){
<a name="508" href="#508">508</a>             <em class="comment">// Ok, so we don't have a ready queue, wait until the top one</em>
<a name="509" href="#509">509</a>             <em class="comment">// will become available.</em>
<a name="510" href="#510">510</a>             <strong>long</strong> waitTime = hq.getNextReadyTime() - System.currentTimeMillis();
<a name="511" href="#511">511</a>             <strong>if</strong>(waitTime > 0){
<a name="512" href="#512">512</a>                 wait(waitTime);
<a name="513" href="#513">513</a>             }
<a name="514" href="#514">514</a>             <em class="comment">// The top HQ may have changed, so get it again</em>
<a name="515" href="#515">515</a>             hq = hostQueues.getTopHQ(); 
<a name="516" href="#516">516</a>         }             
<a name="517" href="#517">517</a> 
<a name="518" href="#518">518</a>         <strong>if</strong>(shouldTerminate){
<a name="519" href="#519">519</a>             <em class="comment">// May have been terminated while thread was waiting for IO</em>
<a name="520" href="#520">520</a>             <strong>throw</strong> <strong>new</strong> <a href="../../../../org/archive/crawler/framework/exceptions/EndedException.html">EndedException</a>(<span class="string">"terminated"</span>);
<a name="521" href="#521">521</a>         }
<a name="522" href="#522">522</a>         
<a name="523" href="#523">523</a>         <strong>try</strong> {
<a name="524" href="#524">524</a>             <a href="../../../../org/archive/crawler/datamodel/CrawlURI.html">CrawlURI</a> curi = hq.next();
<a name="525" href="#525">525</a>             <em class="comment">// Populate CURI with 'transient' variables such as server.</em>
<a name="526" href="#526">526</a>             logger.fine(<span class="string">"Issuing "</span> + curi.toString());
<a name="527" href="#527">527</a>             <strong>long</strong> temp = curi.getLong(A_TIME_OF_NEXT_PROCESSING);
<a name="528" href="#528">528</a>             <strong>long</strong> currT = System.currentTimeMillis();
<a name="529" href="#529">529</a>             <strong>long</strong> overdue = (currT-temp);
<a name="530" href="#530">530</a>             <strong>if</strong>(logger.isLoggable(Level.FINER)){
<a name="531" href="#531">531</a>                 String waitI = <span class="string">"not set"</span>;