// RankingProcess.java
// (C) 2007 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 07.11.2007 on http://yacy.net
//
// This is a part of YaCy, a peer-to-peer based web search engine
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// LICENSE
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package de.anomic.search;
import java.io.File;
import java.io.IOException;
import java.util.Comparator;
import java.util.ConcurrentModificationException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
import net.yacy.cora.document.MultiProtocolURI;
import net.yacy.cora.document.UTF8;
import net.yacy.cora.protocol.Scanner;
import net.yacy.cora.storage.ConcurrentScoreMap;
import net.yacy.cora.storage.ClusteredScoreMap;
import net.yacy.cora.storage.ScoreMap;
import net.yacy.cora.storage.WeakPriorityBlockingQueue;
import net.yacy.cora.storage.WeakPriorityBlockingQueue.ReverseElement;
import net.yacy.document.Condenser;
import net.yacy.kelondro.data.meta.URIMetadataRow;
import net.yacy.kelondro.data.word.Word;
import net.yacy.kelondro.data.word.WordReference;
import net.yacy.kelondro.data.word.WordReferenceVars;
import net.yacy.kelondro.index.BinSearch;
import net.yacy.kelondro.logging.Log;
import net.yacy.kelondro.order.Digest;
import net.yacy.kelondro.rwi.ReferenceContainer;
import net.yacy.kelondro.rwi.TermSearch;
import net.yacy.kelondro.util.EventTracker;
import net.yacy.kelondro.util.FileUtils;
import de.anomic.yacy.graphics.ProfilingGraph;
public final class RankingProcess extends Thread {
public static BinSearch[] ybrTables = null; // block-rank tables
private static final int maxYBR = 3; // the lower this value, the faster the search
private static boolean useYBR = true;
private static final int maxDoubleDomAll = 1000, maxDoubleDomSpecial = 10000;
private final QueryParams query;
private final SortedSet<byte[]> urlhashes; // map for double-check; String/Long relation, addresses ranking number (backreference for deletion)
private final int[] flagcount; // flag counter
private final SortedSet<byte[]> misses; // contains url-hashes that could not been found in the LURL-DB
//private final int[] domZones;
private SortedMap<byte[], ReferenceContainer<WordReference>> localSearchInclusion;
private int remote_resourceSize, remote_indexCount, remote_peerCount;
private int local_resourceSize, local_indexCount;
private final WeakPriorityBlockingQueue<WordReferenceVars> stack;
private int feeders;
private final ConcurrentHashMap<String, WeakPriorityBlockingQueue<WordReferenceVars>> doubleDomCache; // key = domhash (6 bytes); value = like stack
//private final HandleSet handover; // key = urlhash; used for double-check of urls that had been handed over to search process
private final ScoreMap<String> ref; // reference score computation for the commonSense heuristic
private final ScoreMap<String> hostNavigator; // a counter for the appearance of the host hash
private final Map<String, String> hostResolver; // a mapping from a host hash (6 bytes) to the full url hash of one of these urls that have the host hash
private final ScoreMap<String> authorNavigator;
private final ScoreMap<String> namespaceNavigator;
private final ReferenceOrder order;
private final long startTime;
private boolean addRunning;
public RankingProcess(final QueryParams query, final ReferenceOrder order, final int maxentries) {
// we collect the urlhashes and construct a list with urlEntry objects
// attention: if minEntries is too high, this method will not terminate within the maxTime
// sortorder: 0 = hash, 1 = url, 2 = ranking
this.addRunning = true;
this.localSearchInclusion = null;
this.stack = new WeakPriorityBlockingQueue<WordReferenceVars>(maxentries);
this.doubleDomCache = new ConcurrentHashMap<String, WeakPriorityBlockingQueue<WordReferenceVars>>();
this.query = query;
this.order = order;
this.remote_peerCount = 0;
this.remote_resourceSize = 0;
this.remote_indexCount = 0;
this.local_resourceSize = 0;
this.local_indexCount = 0;
this.urlhashes = new TreeSet<byte[]>(URIMetadataRow.rowdef.objectOrder);
//this.urlhashes = new HandleSet(URIMetadataRow.rowdef.primaryKeyLength, URIMetadataRow.rowdef.objectOrder, 0);
this.misses = new TreeSet<byte[]>(URIMetadataRow.rowdef.objectOrder);
//this.misses = new HandleSet(URIMetadataRow.rowdef.primaryKeyLength, URIMetadataRow.rowdef.objectOrder, 0);
this.flagcount = new int[32];
for (int i = 0; i < 32; i++) {this.flagcount[i] = 0;}
this.hostNavigator = new ConcurrentScoreMap<String>();
this.hostResolver = new ConcurrentHashMap<String, String>();
this.authorNavigator = new ConcurrentScoreMap<String>();
this.namespaceNavigator = new ConcurrentScoreMap<String>();
this.ref = new ConcurrentScoreMap<String>();
this.feeders = 1;
this.startTime = System.currentTimeMillis();
}
public QueryParams getQuery() {
return this.query;
}
public ReferenceOrder getOrder() {
return this.order;
}
@Override
public void run() {
// do a search
// sort the local containers and truncate it to a limited count,
// so following sortings together with the global results will be fast
try {
long timer = System.currentTimeMillis();
final TermSearch<WordReference> search = this.query.getSegment().termIndex().query(
query.queryHashes,
query.excludeHashes,
null,
Segment.wordReferenceFactory,
query.maxDistance);
this.localSearchInclusion = search.inclusion();
final ReferenceContainer<WordReference> index = search.joined();
EventTracker.update(EventTracker.EClass.SEARCH, new ProfilingGraph.searchEvent(query.id(true), SearchEvent.Type.JOIN, query.queryString, index.size(), System.currentTimeMillis() - timer), false);
if (index.isEmpty()) {
return;
}
add(index, true, "local index: " + this.query.getSegment().getLocation(), -1, true);
} catch (final Exception e) {
Log.logException(e);
} finally {
oneFeederTerminated();
}
}
public void add(
final ReferenceContainer<WordReference> index,
final boolean local,
String resourceName,
final int fullResource,
final boolean finalizeAddAtEnd) {
// we collect the urlhashes and construct a list with urlEntry objects
// attention: if minEntries is too high, this method will not terminate within the maxTime
this.addRunning = true;
assert (index != null);
if (index.isEmpty()) return;
if (local) {
this.local_resourceSize += index.size();
} else {
assert fullResource >= 0;
this.remote_resourceSize += fullResource;
this.remote_peerCount++;
}
long timer = System.currentTimeMillis();
// normalize entries
final BlockingQueue<WordReferenceVars> decodedEntries = this.order.normalizeWith(index);
EventTracker.update(EventTracker.EClass.SEARCH, new ProfilingGraph.searchEvent(query.id(true), SearchEvent.Type.NORMALIZING, resourceName, index.size(), System.currentTimeMillis() - timer), false);
// iterate over normalized entries and select some that are better than currently stored
timer = System.currentTimeMillis();
boolean nav_hosts = this.query.navigators.equals("all") || this.query.navigators.indexOf("hosts") >= 0;
// apply all constraints
try {
WordReferenceVars iEntry;
while (true) {
iEntry = decodedEntries.poll(1, TimeUnit.SECONDS);
if (iEntry == null || iEntry == WordReferenceVars.poison) break;
assert (iEntry.metadataHash().length == index.row().primaryKeyLength);
//if (iEntry.urlHash().length() != index.row().primaryKeyLength) continue;
// increase flag counts
for (int j = 0; j < 32; j++) {
if (iEntry.flags().get(j)) {flagcount[j]++;}
}
// check constraints
if (!testFlags(iEntry)) {
continue;
}
// check document domain
if (query.contentdom != ContentDomain.TEXT) {
if ((query.contentdom == ContentDomain.AUDIO) && (!(iEntry.flags().get(Condenser.flag_cat_hasaudio)))) continue;
if ((query.contentdom == ContentDomain.VIDEO) && (!(iEntry.flags().get(Condenser.flag_cat_hasvideo)))) continue;
if ((query.contentdom == ContentDomain.IMAGE) && (!(iEntry.flags().get(Condenser.flag_cat_hasimage)))) continue;
if ((query.contentdom == ContentDomain.APP ) && (!(iEntry.flags().get(Condenser.flag_cat_hasapp )))) continue;
}
// check tld domain
/*
if ((DigestURI.domDomain(iEntry.metadataHash()) & this.query.zonecode) == 0) {
// filter out all tld that do not match with wanted tld domain
continue;
}
*/
// count domZones
//this.domZones[DigestURI.domDomain(iEntry.metadataHash())]++;
// check site constraints
String domhash = UTF8.String(iEntry.metadataHash(), 6, 6);
if (query.sitehash == null) {
// no site constraint there; maybe collect host navigation information
if (nav_hosts && query.urlMask_isCatchall) {
this.hostNavigator.inc(domhash);
this.hostResolver.put(domhash, UTF8.String(iEntry.metadataHash()));
}
} else {
if (!domhash.equals(query.sitehash)) {
// filter out all domains that do not match with the site constraint
continue;
}
}
// finally make a double-check and insert result to stack
if (urlhashes.add(iEntry.metadataHash())) {
stack.put(new ReverseElement<WordReferenceVars>(iEntry, this.order.cardinal(iEntry))); // inserts the element and removes the worst (which is smallest)
// increase counter for statistics
if (local) this.local_indexCount++; else this.remote_indexCount++;
}
}
} catch (InterruptedException e) {} finally {
if (finalizeAddAtEnd) this.addRunning = false;
}
//if ((query.neededResults() > 0) && (container.size() > query.neededResults())) remove(true, true);
EventTracker.update(EventTracker.EClass.SEARCH, new ProfilingGraph.searchEvent(query.id(true), SearchEvent.Type.PRESORT, resourceName, index.size(), System.currentTimeMillis() - timer), false);
}
/**
* method to signal the incoming stack that one feeder has terminated
*/
public void oneFeederTerminated() {
this.feeders--;
assert this.feeders >= 0 : "feeders = " + this.feeders;
}
protected void moreFeeders(final int countMoreFeeders) {
this.feeders += countMoreFeeders;
}
public boolean feedingIsFinished() {
return System.currentTimeMillis() - this.startTime > 50 && this.feeders == 0;
}
private boolean testFlags(final WordReference ientry) {
if (query.constraint == null) return true;
// test if ientry matches with filter
// if all = true: let only entries pass that has all matching bits
// if all = false: let all entries pass that has at least one matching bit
if (query.allofconstraint) {
for (int i = 0; i < 32; i++) {
if ((query.constraint.get(i)) && (!ientry.flags().get(i))) return false;
}
return true;
}
for (int i = 0; i < 32; i++) {
if ((query.constraint.get(i)) && (ientry.flags().get(i))) return true;
}
return false;
}
protected Map<byte[], ReferenceContainer<WordReference>> searchContainerMap() {
// direct access to the result maps is needed for abstract generation
// this is only available if execQuery() was called before
return localSearchInclusion;
}
private WeakPriorityBlockingQueue.Element<WordReferenceVars> takeRWI(final boolean skipDoubleDom, final long waitingtime) {
// returns from the current RWI list the best entry and removes this entry from the list
WeakPriorityBlockingQueue<WordReferenceVars> m;
WeakPriorityBlockingQueue.Element<WordReferenceVars> rwi = null;
// take one entry from the stack if there are entries on that stack or the feeding is not yet finished
try {
//System.out.println("stack.poll: feeders = " + this.feeders + ", stack.sizeQueue = " + stack.sizeQueue());
int loops = 0; // a loop counter to terminate the reading if all the results are from the same domain
long timeout = System.currentTimeMillis() + waitingtime;
while (((!feedingIsFinished() && this.addRunning) || stack.sizeQueue() > 0) &&
(this.query.itemsPerPage < 1 || loops++ < this.query.itemsPerPage)) {
if (waitingtime <= 0) {
rwi = stack.poll();
} else timeoutloop:while (System.currentTimeMillis() < timeout) {
if (feedingIsFinished() && stack.sizeQueue() == 0) break timeoutloop;
rwi = stack.poll(50);
if (rwi != null) break timeoutloop;
}
if (rwi == null) break;
if (!skipDoubleDom) {
//System.out.println("!skipDoubleDom");
return rwi;
}
// check doubledom
final String domhash = UTF8.String(rwi.getElement().metadataHash(), 6, 6);
synchronized (this.doubleDomCache) {
m = this.doubleDomCache.get(domhash);
if (m == null) {
// first appearance of dom. we create an entry to signal that one of that domain was already returned
m = new WeakPriorityBlockingQueue<WordReferenceVars>((query.specialRights) ? maxDoubleDomSpecial : maxDoubleDomAll);
this.doubleDomCache.put(domhash, m);
return rwi;
}
// second appearances of dom
m.put(rwi);
}
}
} catch (InterruptedException e1) {}
if (this.doubleDomCache.isEmpty()) return null;
// no more entries in sorted RWI entries. Now take Elements from the doubleDomCache
// find best entry from all caches
WeakPriorityBlockingQueue.Element<WordReferenceVars> bestEntry = null;
WeakPriorityBlockingQueue.Element<WordReferenceVars> o;
synchronized (this.doubleDomCache) {
final Iterator<WeakPriorityBlockingQueue<WordReferenceVars>> i = this.doubleDomCache.values().iterator();
while (i.hasNext()) {
try {
m = i.next();
} catch (ConcurrentModificationException e) {
Log.logException(e);
continue; // not the best solution...
}
if (m == null) continue;
if (m.isEmpty()) continue;
if (bestEntry == null) {
bestEntry = m.peek();
continue;
}
o = m.peek();
if (o == null) continue;
if (o.getWeight() < bestEntry.getWeight()) {
bestEntry = o;
}
}
if (bestEntry == null) return null;
// finally remove the best entry from the doubledom cache
m = this.doubleDomCache.get(UTF8.String(bestEntry.getElement().metadataHash()).substring(6));
bestEntry = m.poll();
}
return bestEntry;
}
/**
* get one metadata entry from the ranked results. This will be the 'best' entry so far
* according to the applied ranking. If there are no more entries left or the timeout
* limit is reached then null is returned. The caller may distinguish the timeout case
* from the case where there will be no more also in the future by calling this.feedingIsFinished()
* @param skipDoubleDom should be true if it is wanted that double domain entries are skipped
* @param waitingtime the time this method may take for a result computation
* @return a metadata entry for a url
*/
public URIMetadataRow takeURL(final boolean skipDoubleDom, final long waitingtime) {
// returns from the current RWI list the best URL entry and removes this entry from the list
final long timeout = System.currentTimeMillis() + Math.max(10, waitingtime);
int p = -1;
byte[] urlhash;
long timeleft;
while ((timeleft = timeout - System.currentTimeMillis()) > 0) {
//System.out.println("timeleft = " + timeleft);
final WeakPriorityBlockingQueue.Element<WordReferenceVars> obrwi = takeRWI(skipDoubleDom, timeleft);
if (obrwi == null) return null; // all time was already wasted in takeRWI to get another element
urlhash = obrwi.getElement().metadataHash();
final URIMetadataRow page = this.query.getSegment().urlMetadata().load(urlhash, obrwi.getElement(), obrwi.getWeight());
if (page == null) {
misses.add(obrwi.getElement().metadataHash());
continue;
}
// prepare values for constraint check
final URIMetadataRow.Components metadata = page.metadata();
// check errors
if (metadata == null) {
continue; // rare case where the url is corrupted
}
if (!query.urlMask_isCatchall) {
// check url mask
if (!metadata.matches(query.urlMask)) {
continue;
}
// in case that we do not have e catchall filter for urls
// we must also construct the domain navigator here
//if (query.sitehash == null) {
// this.hostNavigator.inc(UTF8.String(urlhash, 6, 6));
// this.hostResolver.put(UTF8.String(urlhash, 6, 6), UTF8.String(urlhash));
//}
}
// check for more errors
if (metadata.url() == null) {
continue; // rare case where the url is corrupted
}
final String pageurl = metadata.url().toNormalform(true, true);
final String pageauthor = metadata.dc_creator();
final String pagetitle = metadata.dc_title().toLowerCase();
// check exclusion
if ((QueryParams.anymatch(pagetitle, query.excludeHashes)) ||
(QueryParams.anymatch(pageurl.toLowerCase(), query.excludeHashes)) ||
(QueryParams.anymatch(pageauthor.toLowerCase(), query.excludeHashes))) {
continue;
}
// check index-of constraint
if ((query.constraint != null) &&
(query.constraint.get(Condenser.flag_cat_indexof)) &&
(!(pagetitle.startsWith("index of")))) {
final Iterator<byte[]> wi = query.queryHashes.iterator();
while (wi.hasNext()) {
this.query.getSegment().termIndex().removeDelayed(wi.next(), page.hash());
}
continue;
}
// check location constraint
if ((query.constraint != null) &&
(query.constraint.get(Condenser.flag_cat_haslocation)) &&
(metadata.lat() == 0.0f || metadata.lon() == 0.0f)) {
continue;
}
// check content domain
if ((query.contentdom == ContentDomain.AUDIO && page.laudio() == 0) ||
(query.contentdom == ContentDomain.VIDEO && page.lvideo() == 0) ||
(query.contentdom == ContentDomain.IMAGE && page.limage() == 0) ||
(query.contentdom == ContentDomain.APP && page.lapp() == 0)) {
continue;
}
// evaluate information of metadata for navigation
// author navigation:
if (pageauthor != null && pageauthor.length() > 0) {
// add author to the author navigator
String authorhash = UTF8.String(Word.word2hash(pageauthor));
// check if we already are filtering for authors
if (this.query.authorhash != null && !this.query.authorhash.equals(authorhash)) {
continue;
}
// add author to the author navigator
this.authorNavigator.inc(pageauthor);
} else if (this.query.authorhash != null) {
continue;
}
// namespace navigation
String pagepath = metadata.url().getPath();
if ((p = pagepath.indexOf(':')) >= 0) {
pagepath = pagepath.substring(0,p);
p = pagepath.lastIndexOf('/');
if (p >= 0) {
pagepath = pagepath.substring(p + 1);
this.namespaceNavigator.inc(pagepath);
}
}
// check Scanner
if (!Scanner.acceptURL(metadata.url())) {
continue;
}
// accept url
return page;
}
return null;
}
public int sizeQueue() {
int c = stack.sizeQueue();
for (WeakPriorityBlockingQueue<WordReferenceVars> s: this.doubleDomCache.values()) {
c += s.sizeQueue();
}
return c;
}
public int sizeAvailable() {
int c = stack.sizeAvailable();
for (WeakPriorityBlockingQueue<WordReferenceVars> s: this.doubleDomCache.values()) {
c += s.sizeAvailable();
}
return c;
}
public boolean isEmpty() {
if (!stack.isEmpty()) return false;
for (WeakPriorityBlockingQueue<WordReferenceVars> s: this.doubleDomCache.values()) {
if (!s.isEmpty()) return false;
}
return true;
}
public int[] flagCount() {
return flagcount;
}
// "results from a total number of <remote_resourceSize + local_resourceSize> known (<local_resourceSize> local, <remote_resourceSize> remote), <remote_indexCount> links from <remote_peerCount> other YaCy peers."
public int filteredCount() {
// the number of index entries that are considered as result set
return this.stack.sizeAvailable();
}
public int getLocalIndexCount() {
// the number of results in the local peer after filtering
return this.local_indexCount;
}
public int getRemoteIndexCount() {
// the number of result contributions from all the remote peers
return this.remote_indexCount;
}
public int getRemoteResourceSize() {
// the number of all hits in all the remote peers
return Math.max(this.remote_resourceSize, this.remote_indexCount);
}
public int getRemotePeerCount() {
// the number of remote peers that have contributed
return this.remote_peerCount;
}
public Iterator<byte[]> miss() {
return this.misses.iterator();
}
public int getMissCount() {
return this.misses.size();
}
public ScoreMap<String> getNamespaceNavigator() {
if (!this.query.navigators.equals("all") && this.query.navigators.indexOf("namespace") < 0) return new ClusteredScoreMap<String>();
if (this.namespaceNavigator.sizeSmaller(2)) this.namespaceNavigator.clear(); // navigators with one entry are not useful
return this.namespaceNavigator;
}
public ScoreMap<String> getHostNavigator() {
ScoreMap<String> result = new ConcurrentScoreMap<String>();
if (!this.query.navigators.equals("all") && this.query.navigators.indexOf("hosts") < 0) return result;
final Iterator<String> domhashs = this.hostNavigator.keys(false);
URIMetadataRow row;
String domhash, urlhash, hostname;
if (this.hostResolver != null) while (domhashs.hasNext() && result.sizeSmaller(30)) {
domhash = domhashs.next();
if (domhash == null) continue;
urlhash = this.hostResolver.get(domhash);
row = urlhash == null ? null : this.query.getSegment().urlMetadata().load(UTF8.getBytes(urlhash), null, 0);
hostname = row == null ? null : row.metadata().url().getHost();
if (hostname != null) {
result.set(hostname, this.hostNavigator.get(domhash));
}
}
if (result.sizeSmaller(2)) result.clear(); // navigators with one entry are not useful
return result;
}
public static final Comparator<Map.Entry<String, Integer>> mecomp = new Comparator<Map.Entry<String, Integer>>() {
public int compare(Map.Entry<String, Integer> o1, Map.Entry<String, Integer> o2) {
if (o1.getValue().intValue() < o2.getValue().intValue()) return 1;
if (o2.getValue().intValue() < o1.getValue().intValue()) return -1;
return 0;
}
};
public ScoreMap<String> getTopicNavigator(int count) {
// create a list of words that had been computed by statistics over all
// words that appeared in the url or the description of all urls
final ScoreMap<String> result = new ConcurrentScoreMap<String>();
if (!this.query.navigators.equals("all") && this.query.navigators.indexOf("topics") < 0) return result;
if (this.ref.sizeSmaller(2)) this.ref.clear(); // navigators with one entry are not useful
final Map<String, Float> counts = new HashMap<String, Float>();
final Iterator<String> i = this.ref.keys(false);
String word;
byte[] termHash;
int c;
float q, min = Float.MAX_VALUE, max = Float.MIN_VALUE;
int ic = count;
while (ic-- > 0 && i.hasNext()) {
word = i.next();
if (word == null) continue;
termHash = Word.word2hash(word);
c = this.query.getSegment().termIndex().count(termHash);
if (c > 0) {
q = ((float) this.ref.get(word)) / ((float) c);
min = Math.min(min, q);
max = Math.max(max, q);
counts.put(word, q);
}
}
if (max > min) for (Map.Entry<String, Float> ce: counts.entrySet()) {
result.set(ce.getKey(), (int) (((double) count) * (ce.getValue() - min) / (max - min)));
}
return this.ref;
}
public void addTopic(final String[] words) {
String word;
for (final String w : words) {
word = w.toLowerCase();
if (word.length() > 2 &&
"http_html_php_ftp_www_com_org_net_gov_edu_index_home_page_for_usage_the_and_zum_der_die_das_und_the_zur_bzw_mit_blog_wiki_aus_bei_off".indexOf(word) < 0 &&
!query.queryHashes.has(Word.word2hash(word)) &&
word.matches("[a-z]+") &&
!Switchboard.badwords.contains(word) &&
!Switchboard.stopwords.contains(word)) {
ref.inc(word);
}
}
}
protected void addTopics(final ResultEntry resultEntry) {
// take out relevant information for reference computation
if ((resultEntry.url() == null) || (resultEntry.title() == null)) return;
//final String[] urlcomps = htmlFilterContentScraper.urlComps(resultEntry.url().toNormalform(true, true)); // word components of the url
final String[] descrcomps = MultiProtocolURI.splitpattern.split(resultEntry.title().toLowerCase()); // words in the description
// add references
//addTopic(urlcomps);
addTopic(descrcomps);
}
public ScoreMap<String> getAuthorNavigator() {
// create a list of words that had been computed by statistics over all
// words that appeared in the url or the description of all urls
if (!this.query.navigators.equals("all") && this.query.navigators.indexOf("authors") < 0) return new ConcurrentScoreMap<String>();
if (this.authorNavigator.sizeSmaller(2)) this.authorNavigator.clear(); // navigators with one entry are not useful
return this.authorNavigator;
}
/**
* load YaCy Block Rank tables
* These tables have a very simple structure: every file is a sequence of Domain hashes, ordered by b64.
* Each Domain hash has a length of 6 bytes and there is no separation character between the hashes
* @param rankingPath
* @param count
*/
public static void loadYBR(final File rankingPath, final int count) {
// load ranking tables
if (rankingPath.exists()) {
ybrTables = new BinSearch[count];
String ybrName;
File f;
try {
for (int i = 0; i < count; i++) {
ybrName = "YBR-4-" + Digest.encodeHex(i, 2) + ".idx";
f = new File(rankingPath, ybrName);
if (f.exists()) {
ybrTables[i] = new BinSearch(FileUtils.read(f), 6);
} else {
ybrTables[i] = null;
}
}
} catch (final IOException e) {
ybrTables = null;
}
} else {
ybrTables = null;
}
}
public static boolean canUseYBR() {
return ybrTables != null;
}
public static boolean isUsingYBR() {
return useYBR;
}
public static void switchYBR(final boolean usage) {
useYBR = usage;
}
public static int ybr(final byte[] urlHash) {
// returns the YBR value in a range of 0..15, where 0 means best ranking and 15 means worst ranking
if (ybrTables == null) return 15;
if (!(useYBR)) return 15;
byte[] domhash = new byte[6];
System.arraycopy(urlHash, 6, domhash, 0, 6);
final int m = Math.min(maxYBR, ybrTables.length);
for (int i = 0; i < m; i++) {
if ((ybrTables[i] != null) && (ybrTables[i].contains(domhash))) {
return i;
}
}
return 15;
}
}