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539 lines
22 KiB
539 lines
22 KiB
// TextSnippet.java
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// -----------------
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// (C) by Michael Peter Christen; mc@yacy.net
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// first published on http://www.anomic.de
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// Frankfurt, Germany, 2005
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//
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// $LastChangedDate$
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// $LastChangedRevision$
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// $LastChangedBy$
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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package net.yacy.search.snippet;
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import java.io.IOException;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.Comparator;
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import java.util.HashSet;
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import java.util.Iterator;
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import java.util.Set;
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import java.util.regex.Pattern;
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import net.yacy.cora.document.ASCII;
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import net.yacy.cora.federate.yacy.CacheStrategy;
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import net.yacy.cora.order.Base64Order;
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import net.yacy.cora.protocol.ClientIdentification;
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import net.yacy.cora.storage.ARC;
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import net.yacy.cora.storage.ConcurrentARC;
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import net.yacy.cora.storage.HandleSet;
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import net.yacy.cora.util.ByteArray;
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import net.yacy.cora.util.ByteBuffer;
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import net.yacy.crawler.retrieval.Request;
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import net.yacy.crawler.retrieval.Response;
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import net.yacy.document.Document;
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import net.yacy.document.Parser;
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import net.yacy.document.SentenceReader;
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import net.yacy.document.SnippetExtractor;
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import net.yacy.document.WordTokenizer;
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import net.yacy.document.parser.html.CharacterCoding;
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import net.yacy.kelondro.data.meta.DigestURI;
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import net.yacy.kelondro.data.meta.URIMetadataNode;
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import net.yacy.kelondro.data.word.Word;
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import net.yacy.peers.RemoteSearch;
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import net.yacy.repository.Blacklist.BlacklistType;
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import net.yacy.repository.LoaderDispatcher;
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import net.yacy.search.Switchboard;
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import net.yacy.search.query.QueryGoal;
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public class TextSnippet implements Comparable<TextSnippet>, Comparator<TextSnippet> {
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private static final int MAX_CACHE = 1000;
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/**
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* <code>\\A[^\\p{L}\\p{N}].+</code>
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*/
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private static final Pattern p1 =
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Pattern.compile("\\A[^\\p{L}\\p{N}].+");
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/**
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* <code>.+[^\\p{L}\\p{N}]\\Z</code>
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*/
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private static final Pattern p2 =
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Pattern.compile(".+[^\\p{L}\\p{N}]\\Z");
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/**
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* <code>\\A[\\p{L}\\p{N}]+[^\\p{L}\\p{N}].+\\Z</code>
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*/
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private static final Pattern p3 =
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Pattern.compile("\\A[\\p{L}\\p{N}]+[^\\p{L}\\p{N}].+\\Z");
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/**
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* <code>[^\\p{L}\\p{N}]</code>
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*/
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private static final Pattern p4 =
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Pattern.compile("[^\\p{L}\\p{N}]");
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public static class Cache {
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private final ARC<String, String> cache;
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public Cache() {
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this.cache = new ConcurrentARC<String, String>(MAX_CACHE, Math.min(32, 2 * Runtime.getRuntime().availableProcessors()));
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}
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public void put(final String wordhashes, final String urlhash, final String snippet) {
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// generate key
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final String key = urlhash + wordhashes;
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// do nothing if snippet is known or otherwise learn new snippet
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this.cache.insertIfAbsent(key, snippet);
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}
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public String get(final String wordhashes, final String urlhash) {
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// generate key
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final String key = urlhash + wordhashes;
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return this.cache.get(key);
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}
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public boolean contains(final String wordhashes, final String urlhash) {
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return this.cache.containsKey(urlhash + wordhashes);
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}
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}
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public static final Cache snippetsCache = new Cache();
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public static enum ResultClass {
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SOURCE_CACHE(false),
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SOURCE_FILE(false),
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SOURCE_WEB(false),
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SOURCE_METADATA(false),
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ERROR_NO_HASH_GIVEN(true),
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ERROR_SOURCE_LOADING(true),
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ERROR_RESOURCE_LOADING(true),
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ERROR_PARSER_FAILED(true),
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ERROR_PARSER_NO_LINES(true),
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ERROR_NO_MATCH(true);
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private final boolean fail;
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private ResultClass(final boolean fail) {
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this.fail = fail;
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}
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public boolean fail() {
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return this.fail;
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}
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}
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private byte[] urlhash;
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private String line;
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private boolean isMarked;
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private String error;
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private ResultClass resultStatus;
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public TextSnippet(
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final byte[] urlhash,
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final String line,
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final boolean isMarked,
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final ResultClass errorCode,
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final String errortext) {
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init(urlhash, line, isMarked, errorCode, errortext);
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}
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public TextSnippet(
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final LoaderDispatcher loader,
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final URIMetadataNode row,
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final HandleSet queryhashes,
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final CacheStrategy cacheStrategy,
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final boolean pre,
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final int snippetMaxLength,
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final boolean reindexing) {
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// heise = "0OQUNU3JSs05"
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final DigestURI url = row.url();
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if (queryhashes.isEmpty()) {
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//System.out.println("found no queryhashes for URL retrieve " + url);
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init(url.hash(), null, false, ResultClass.ERROR_NO_HASH_GIVEN, "no query hashes given");
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return;
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}
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// try to get snippet from snippetCache
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final ResultClass source = ResultClass.SOURCE_CACHE;
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final String wordhashes = RemoteSearch.set2string(queryhashes);
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final String urls = ASCII.String(url.hash());
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String snippetLine = snippetsCache.get(wordhashes, urls);
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if (snippetLine != null) {
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// found the snippet
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init(url.hash(), snippetLine, false, source, null);
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return;
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}
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// try to get the snippet from a document at the cache (or in the web)
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// this requires that the document is parsed after loading
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String textline = null;
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HandleSet remainingHashes = queryhashes.clone();
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{ //encapsulate potential expensive sentences
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Collection<StringBuilder> sentences = null;
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// try to get the snippet from metadata
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removeMatchingHashes(row.url().toTokens(), remainingHashes);
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removeMatchingHashes(row.dc_title(), remainingHashes);
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removeMatchingHashes(row.dc_creator(), remainingHashes);
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removeMatchingHashes(row.dc_subject(), remainingHashes);
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if (!remainingHashes.isEmpty()) {
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// we did not find everything in the metadata, look further into the document itself.
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// first acquire the sentences:
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final String solrText = row.getText();
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if (solrText != null) {
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// compute sentences from solr query
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final SentenceReader sr = new SentenceReader(solrText, pre);
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sentences = new ArrayList<StringBuilder>();
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while (sr.hasNext()) {
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sentences.add(sr.next());
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}
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} else if (net.yacy.crawler.data.Cache.has(url.hash())) {
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// get the sentences from the cache
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final Request request = loader == null ? null : loader.request(url, true, reindexing);
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Response response;
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try {
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response = loader == null || request == null ? null : loader.load(request, CacheStrategy.CACHEONLY, BlacklistType.SEARCH, ClientIdentification.yacyIntranetCrawlerAgent);
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} catch (final IOException e1) {
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response = null;
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}
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Document document = null;
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if (response != null) {
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try {
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document = Document.mergeDocuments(response.url(), response.getMimeType(), response.parse());
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sentences = document.getSentences(pre);
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} catch (final Parser.Failure e) {
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}
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}
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}
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if (sentences == null) {
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// not found the snippet
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init(url.hash(), null, false, ResultClass.SOURCE_METADATA, null);
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return;
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}
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if (sentences.size() > 0) {
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try {
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final SnippetExtractor tsr = new SnippetExtractor(sentences, remainingHashes, snippetMaxLength);
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textline = tsr.getSnippet();
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remainingHashes = tsr.getRemainingWords();
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} catch (final UnsupportedOperationException e) {
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init(url.hash(), null, false, ResultClass.ERROR_NO_MATCH, "snippet extractor failed:" + e.getMessage());
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return;
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}
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}
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}
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if (remainingHashes.isEmpty()) {
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// we found the snippet
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if (textline == null) {
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if (sentences == null) {
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textline = row.dc_subject();
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} else {
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// use the first lines from the text as snippet
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final StringBuilder s = new StringBuilder(snippetMaxLength);
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for (final StringBuilder t: sentences) {
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s.append(t).append(' ');
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if (s.length() >= snippetMaxLength / 4 * 3) break;
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}
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if (s.length() > snippetMaxLength) { s.setLength(snippetMaxLength); s.trimToSize(); }
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textline = s.toString();
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}
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}
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init(url.hash(), textline.length() > 0 ? textline : this.line, false, ResultClass.SOURCE_METADATA, null);
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return;
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}
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// try to load the resource from the cache
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Response response = null;
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try {
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response = loader == null ? null : loader.load(loader.request(url, true, reindexing), (url.isFile() || url.isSMB()) ? CacheStrategy.NOCACHE : (cacheStrategy == null ? CacheStrategy.CACHEONLY : cacheStrategy), BlacklistType.SEARCH, ClientIdentification.yacyIntranetCrawlerAgent);
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} catch (final IOException e) {
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response = null;
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}
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if (response == null) {
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// in case that we did not get any result we can still return a success when we are not allowed to go online
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if (cacheStrategy == null || cacheStrategy.mustBeOffline()) {
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init(url.hash(), null, false, ResultClass.ERROR_SOURCE_LOADING, "omitted network load (not allowed), no cache entry");
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return;
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}
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// if it is still not available, report an error
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init(url.hash(), null, false, ResultClass.ERROR_RESOURCE_LOADING, "error loading resource from net, no cache entry");
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return;
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}
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if (!response.fromCache()) {
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// place entry on indexing queue
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Switchboard.getSwitchboard().toIndexer(response);
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this.resultStatus = ResultClass.SOURCE_WEB;
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}
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// parse the document to get all sentenced; available for snippet computation
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Document document = null;
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try {
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document = Document.mergeDocuments(response.url(), response.getMimeType(), response.parse());
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} catch (final Parser.Failure e) {
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init(url.hash(), null, false, ResultClass.ERROR_PARSER_FAILED, e.getMessage()); // cannot be parsed
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return;
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}
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if (document == null) {
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init(url.hash(), null, false, ResultClass.ERROR_PARSER_FAILED, "parser error/failed"); // cannot be parsed
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return;
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}
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// compute sentences from parsed document
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sentences = document.getSentences(pre);
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document.close();
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if (sentences == null) {
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init(url.hash(), null, false, ResultClass.ERROR_PARSER_NO_LINES, "parser returned no sentences");
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return;
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}
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try {
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final SnippetExtractor tsr = new SnippetExtractor(sentences, remainingHashes, snippetMaxLength);
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textline = tsr.getSnippet();
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remainingHashes = tsr.getRemainingWords();
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} catch (final UnsupportedOperationException e) {
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init(url.hash(), null, false, ResultClass.ERROR_NO_MATCH, "snippet extractor failed:" + e.getMessage());
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return;
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}
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} //encapsulate potential expensive sentences END
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// compute snippet from media - attention document closed above!
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//String audioline = computeMediaSnippet(document.getAudiolinks(), queryhashes);
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//String videoline = computeMediaSnippet(document.getVideolinks(), queryhashes);
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//String appline = computeMediaSnippet(document.getApplinks(), queryhashes);
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//String hrefline = computeMediaSnippet(document.getAnchors(), queryhashes);
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//String imageline = computeMediaSnippet(document.getAudiolinks(), queryhashes);
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snippetLine = "";
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//if (audioline != null) line += (line.isEmpty()) ? audioline : "<br />" + audioline;
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//if (videoline != null) line += (line.isEmpty()) ? videoline : "<br />" + videoline;
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//if (appline != null) line += (line.isEmpty()) ? appline : "<br />" + appline;
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//if (hrefline != null) line += (line.isEmpty()) ? hrefline : "<br />" + hrefline;
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//if (textline != null) snippetLine += (snippetLine.isEmpty()) ? textline : "<br />" + textline;
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if (snippetLine == null || !remainingHashes.isEmpty()) {
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init(url.hash(), null, false, ResultClass.ERROR_NO_MATCH, "no matching snippet found");
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return;
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}
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if (snippetLine.length() > snippetMaxLength) snippetLine = snippetLine.substring(0, snippetMaxLength);
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// finally store this snippet in our own cache
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snippetsCache.put(wordhashes, urls, snippetLine);
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// document.close();
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init(url.hash(), snippetLine, false, source, null);
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}
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private void init(
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final byte[] urlhash,
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final String line,
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final boolean isMarked,
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final ResultClass errorCode,
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final String errortext) {
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this.urlhash = urlhash;
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this.line = line;
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this.isMarked = isMarked;
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this.resultStatus = errorCode;
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this.error = errortext;
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}
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public boolean exists() {
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return this.line != null;
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}
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public boolean isMarked() {
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return this.isMarked;
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}
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public String getLineRaw() {
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return (this.line == null) ? "" : this.line;
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}
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public String getError() {
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return (this.error == null) ? "" : this.error.trim();
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}
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public ResultClass getErrorCode() {
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return this.resultStatus;
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}
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private static final Pattern SPLIT_PATTERN = Pattern.compile(" |-");
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/**
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* Marks all words in current line which have the same
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* hash values as the ones contained in argument.
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* @param queryHashes hashes of search words
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* @return line with marked words
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*/
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public String getLineMarked(final QueryGoal queryGoal) {
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final HandleSet queryHashes = queryGoal.getIncludeHashes();
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if (this.line == null) {
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return "";
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}
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if (queryHashes == null || queryHashes.isEmpty()) {
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return this.line.trim();
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}
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if (this.line.endsWith(".")) {
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this.line = this.line.substring(0, this.line.length() - 1);
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}
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final String[] words = SPLIT_PATTERN.split(this.line);
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final Iterator<byte[]> iterator = queryHashes.iterator();
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final Set<byte[]> queryHashesSet = new HashSet<byte[]>();
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while (iterator.hasNext()) {
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queryHashesSet.add(iterator.next());
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}
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for (int i = 0; i < words.length; i++) {
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words[i] = getWordMarked(words[i], queryHashesSet);
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}
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final StringBuilder l =
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new StringBuilder(this.line.length() + queryHashes.size() * 8);
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for (final String word : words) {
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l.append(word);
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l.append(' ');
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}
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return l.toString().trim();
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}
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@Override
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public int compareTo(final TextSnippet o) {
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return Base64Order.enhancedCoder.compare(this.urlhash, o.urlhash);
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}
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@Override
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public int compare(final TextSnippet o1, final TextSnippet o2) {
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return o1.compareTo(o2);
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}
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private int hashCache = Integer.MIN_VALUE; // if this is used in a compare method many times, a cache is useful
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@Override
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public int hashCode() {
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if (this.hashCache == Integer.MIN_VALUE) {
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this.hashCache = ByteArray.hashCode(this.urlhash);
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}
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return this.hashCache;
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}
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@Override
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public String toString() {
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return (this.line == null) ? "" : this.line;
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}
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/**
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* Marks words with <b>-tags. <b>Beware</b>: Method
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* has side effects! Certain characters in words will be
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* escaped to HTML encoding. Using this method a second
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* time with already escaped characters might lead to
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* undesired results.
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* @param word the word to mark
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* @param queryHashes hashes of the words to mark
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* @return the marked word if one of the hashes matches,
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* else the unmarked word
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* @see #getLineMarked(Set)
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*/
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private static String getWordMarked(
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final String word, final Set<byte[]> queryHashes) {
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//note to myself [MN]:
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//For details on regex see "Mastering regular expressions" by J.E.F. Friedl
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//especially p. 123 and p. 390/391 (in the German version of the 2nd edition)
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final StringBuilder theWord = new StringBuilder(word);
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final StringBuilder prefix = new StringBuilder(40);
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final StringBuilder postfix = new StringBuilder(40);
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int len = 0;
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// cut off prefix if it contains of non-characters or non-numbers
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while (p1.matcher(theWord).find()) {
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prefix.append(theWord.substring(0, 1));
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theWord.delete(0, 1);
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}
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// cut off postfix if it contains of non-characters or non-numbers
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while (p2.matcher(theWord).find()) {
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len = theWord.length();
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postfix.insert(0, theWord.substring(len - 1, len));
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theWord.delete(len - 1, len);
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}
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//special treatment if there is a special character in the word
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if (p3.matcher(theWord).find()) {
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StringBuilder out = null;
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String temp = "";
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for (int k = 0; k < theWord.length(); k++) {
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out = new StringBuilder(80);
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//is character a special character?
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if (p4.matcher(theWord.substring(k, k + 1)).find()) {
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if (ByteBuffer.contains(queryHashes, Word.word2hash(temp))) {
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temp = "<b>" + CharacterCoding.unicode2html(temp, false) + "</b>";
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}
|
|
out.append(temp);
|
|
out.append(CharacterCoding.unicode2html(theWord.substring(k, k +1), false));
|
|
temp = "";
|
|
}
|
|
//last character
|
|
else if (k == (theWord.length() - 1)) {
|
|
temp = temp + theWord.substring(k, k + 1);
|
|
if (ByteBuffer.contains(queryHashes, Word.word2hash(temp))) {
|
|
temp = "<b>" + CharacterCoding.unicode2html(temp, false) + "</b>";
|
|
}
|
|
out.append(temp);
|
|
temp = "";
|
|
}
|
|
else {
|
|
temp = temp + theWord.substring(k, k + 1);
|
|
}
|
|
}
|
|
theWord.delete(0, theWord.length());
|
|
theWord.append(out);
|
|
|
|
} else if (ByteBuffer.contains(queryHashes, Word.word2hash(theWord))) {
|
|
theWord.replace(
|
|
0,
|
|
theWord.length(),
|
|
CharacterCoding.unicode2html(theWord.toString(), false));
|
|
theWord.insert(0, "<b>");
|
|
theWord.append("</b>");
|
|
}
|
|
|
|
theWord.insert(
|
|
0,
|
|
CharacterCoding.unicode2html(prefix.toString(), false));
|
|
theWord.append(CharacterCoding.unicode2html(postfix.toString(), false));
|
|
return theWord.toString();
|
|
}
|
|
|
|
private static void removeMatchingHashes(final String sentence, final HandleSet queryhashes) {
|
|
if (queryhashes.size() == 0) return;
|
|
final Set<byte[]> m = WordTokenizer.hashSentence(sentence, null, 100).keySet();
|
|
//for (byte[] b: m) System.out.println("sentence hash: " + ASCII.String(b));
|
|
//for (byte[] b: queryhashes) System.out.println("queryhash: " + ASCII.String(b));
|
|
ArrayList<byte[]> o = new ArrayList<byte[]>(queryhashes.size());
|
|
for (final byte[] b : queryhashes) {
|
|
if (m.contains(b)) o.add(b);
|
|
}
|
|
for (final byte[] b : o) queryhashes.remove(b);
|
|
}
|
|
|
|
}
|