From: David ‘Bombe’ Roden <bombe@pterodactylus.net>
Date: Mon, 16 Mar 2009 23:09:47 +0000 (+0100)
Subject: Remember crawled pages and don’t crawl them again.
X-Git-Url: https://git.pterodactylus.net/?p=arachne.git;a=commitdiff_plain;h=83a84def68ebc8d094bc9837ec72b5fc5cfdd782

Remember crawled pages and don’t crawl them again.
Don’t add pages that are already scheduled for crawling.
---

diff --git a/src/net/pterodactylus/arachne/core/Core.java b/src/net/pterodactylus/arachne/core/Core.java
index 8afe014..9bcddb0 100644
--- a/src/net/pterodactylus/arachne/core/Core.java
+++ b/src/net/pterodactylus/arachne/core/Core.java
@@ -7,7 +7,9 @@ import java.net.MalformedURLException;
 import java.net.URL;
 import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
 import java.util.logging.Level;
@@ -51,6 +53,9 @@ public class Core extends AbstractService {
 	/** The current list of URLs to crawl. */
 	private final List<Page> pages = new ArrayList<Page>();
 
+	/** Already crawled pages. */
+	private final Set<Page> crawledPages = new HashSet<Page>();
+
 	//
 	// ACCESSORS
 	//
@@ -101,8 +106,10 @@ public class Core extends AbstractService {
 	 */
 	public void addPage(Page page) {
 		Validation.begin().isNotNull("page", page).check();
-		pages.add(page);
-		notifySyncObject();
+		if (!crawledPages.contains(page) && !pages.contains(page)) {
+			pages.add(page);
+			notifySyncObject();
+		}
 	}
 
 	//
@@ -115,10 +122,10 @@ public class Core extends AbstractService {
 	 * @see de.ina.util.service.AbstractService#serviceRun()
 	 */
 	@Override
-	@SuppressWarnings("null")
 	protected void serviceRun() {
 		while (!shouldStop()) {
-			Page nextPage = null;
+			final Page nextPage;
+			Page page = null;
 			synchronized (syncObject) {
 				while (!shouldStop() && pages.isEmpty()) {
 					try {
@@ -128,12 +135,13 @@ public class Core extends AbstractService {
 					}
 				}
 				if (!shouldStop()) {
-					nextPage = pages.remove(0);
+					page = pages.remove(0);
 				}
 			}
 			if (shouldStop()) {
 				break;
 			}
+			nextPage = page;
 			URL nextURL = nextPage.toURL(nodeHost, nodePort);
 			if (nextURL == null) {
 				logger.log(Level.INFO, "Skipping “" + nextPage + "”.");
@@ -145,8 +153,10 @@ public class Core extends AbstractService {
 				urlFetcher = new URLFetcher(parserFactory, nextURL);
 				urlFetcherExecutor.execute(new Runnable() {
 
+					@SuppressWarnings("synthetic-access")
 					public void run() {
 						urlFetcher.run();
+						crawledPages.add(nextPage);
 						for (Page page : urlFetcher.getCollectedPages()) {
 							addPage(page);
 						}