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9b3fae9496
*) program to interface, not implementation git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@7345 6c8d7289-2bf4-0310-a012-ef5d649a1542
437 lines
18 KiB
Java
437 lines
18 KiB
Java
// 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 de.anomic.search;
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import java.util.Collection;
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import java.util.Comparator;
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import java.util.Iterator;
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import java.util.List;
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import java.util.SortedMap;
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import java.util.regex.Matcher;
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import java.util.regex.Pattern;
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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.document.Condenser;
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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.SnippetExtractor;
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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.URIMetadataRow;
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import net.yacy.kelondro.data.word.Word;
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import net.yacy.kelondro.index.HandleSet;
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import net.yacy.kelondro.order.Base64Order;
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import net.yacy.kelondro.util.ByteArray;
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import net.yacy.repository.LoaderDispatcher;
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import de.anomic.crawler.CrawlProfile;
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import de.anomic.crawler.retrieval.Response;
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import de.anomic.yacy.yacySearch;
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public class TextSnippet implements Comparable<TextSnippet>, Comparator<TextSnippet> {
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private static final int maxCache = 1000;
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public static final int SOURCE_CACHE = 0;
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public static final int SOURCE_FILE = 1;
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public static final int SOURCE_WEB = 2;
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public static final int SOURCE_METADATA = 3;
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public static final int ERROR_NO_HASH_GIVEN = 11;
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public static final int ERROR_SOURCE_LOADING = 12;
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public static final int ERROR_RESOURCE_LOADING = 13;
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public static final int ERROR_PARSER_FAILED = 14;
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public static final int ERROR_PARSER_NO_LINES = 15;
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public static final int ERROR_NO_MATCH = 16;
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/**
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* <code>\\A[^\\p{L}\\p{N}].+</code>
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*/
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private final static Pattern p1 = 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 final static Pattern p2 = 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 final static Pattern p3 = 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 final static Pattern p4 = Pattern.compile("[^\\p{L}\\p{N}]");
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/**
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* <code>(.*?)(\\<b\\>.+?\\</b\\>)(.*)</code>
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*/
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private final static Pattern p01 = Pattern.compile("(.*?)(\\<b\\>.+?\\</b\\>)(.*)"); // marked words are in <b>-tags
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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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cache = new ConcurrentARC<String, String>(maxCache, Math.max(10, 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
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if (cache.containsKey(key)) return;
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// learn new snippet
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cache.put(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 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 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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private byte[] urlhash;
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private String line;
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private String error;
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private int errorCode;
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public TextSnippet(final byte[] urlhash, final String line, final int errorCode, final String errortext) {
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init(urlhash, line, errorCode, errortext);
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}
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public TextSnippet(final LoaderDispatcher loader, final URIMetadataRow.Components comp, final HandleSet queryhashes, final CrawlProfile.CacheStrategy cacheStrategy, final boolean pre, final int snippetMaxLength, final int maxDocLen, final boolean reindexing) {
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// heise = "0OQUNU3JSs05"
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final DigestURI url = comp.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, 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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int source = SOURCE_CACHE;
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final String wordhashes = yacySearch.set2string(queryhashes);
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final String urls = new 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, source, null);
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return;
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}
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/* ===========================================================================
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* LOAD RESOURCE DATA
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* =========================================================================== */
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// if the snippet is not in the cache, we can try to get it from the htcache
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final Response response;
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try {
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// first try to get the snippet from metadata
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String loc;
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boolean noCacheUsage = url.isFile() || url.isSMB();
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boolean objectWasInCache = (noCacheUsage) ? false : de.anomic.http.client.Cache.has(url);
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boolean useMetadata = !objectWasInCache && !cacheStrategy.mustBeOffline();
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if (useMetadata && containsAllHashes(loc = comp.dc_title(), queryhashes)) {
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// try to create the snippet from information given in the url itself
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init(url.hash(), loc, SOURCE_METADATA, null);
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return;
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} else if (useMetadata && containsAllHashes(loc = comp.dc_creator(), queryhashes)) {
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// try to create the snippet from information given in the creator metadata
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init(url.hash(), loc, SOURCE_METADATA, null);
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return;
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} else if (useMetadata && containsAllHashes(loc = comp.dc_subject(), queryhashes)) {
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// try to create the snippet from information given in the subject metadata
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init(url.hash(), loc, SOURCE_METADATA, null);
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return;
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} else if (useMetadata && containsAllHashes(loc = comp.url().toNormalform(true, true).replace('-', ' '), queryhashes)) {
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// try to create the snippet from information given in the url
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init(url.hash(), loc, SOURCE_METADATA, null);
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return;
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} else {
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// try to load the resource from the cache
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response = loader.load(loader.request(url, true, reindexing), noCacheUsage ? CrawlProfile.CacheStrategy.NOCACHE : cacheStrategy, Long.MAX_VALUE);
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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.mustBeOffline()) {
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init(url.hash(), null, 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, 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 (!objectWasInCache) {
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// place entry on indexing queue
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Switchboard.getSwitchboard().toIndexer(response);
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source = SOURCE_WEB;
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}
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}
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} catch (final Exception e) {
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//Log.logException(e);
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init(url.hash(), null, ERROR_SOURCE_LOADING, "error loading resource: " + e.getMessage());
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return;
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}
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/* ===========================================================================
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* PARSE RESOURCE
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* =========================================================================== */
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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, 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, ERROR_PARSER_FAILED, "parser error/failed"); // cannot be parsed
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return;
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}
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/* ===========================================================================
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* COMPUTE SNIPPET
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* =========================================================================== */
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// we have found a parseable non-empty file: use the lines
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// compute snippet from text
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final Collection<StringBuilder> sentences = document.getSentences(pre);
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if (sentences == null) {
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init(url.hash(), null, ERROR_PARSER_NO_LINES, "parser returned no sentences");
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return;
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}
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final SnippetExtractor tsr;
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String textline = null;
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HandleSet remainingHashes = queryhashes;
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try {
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tsr = new SnippetExtractor(sentences, queryhashes, snippetMaxLength);
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textline = tsr.getSnippet();
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remainingHashes = tsr.getRemainingWords();
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} catch (UnsupportedOperationException e) {
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init(url.hash(), null, ERROR_NO_MATCH, "no matching snippet found");
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return;
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}
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// compute snippet from media
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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.length() == 0) ? audioline : "<br />" + audioline;
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//if (videoline != null) line += (line.length() == 0) ? videoline : "<br />" + videoline;
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//if (appline != null) line += (line.length() == 0) ? appline : "<br />" + appline;
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//if (hrefline != null) line += (line.length() == 0) ? hrefline : "<br />" + hrefline;
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if (textline != null) snippetLine += (snippetLine.length() == 0) ? textline : "<br />" + textline;
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if (snippetLine == null || !remainingHashes.isEmpty()) {
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init(url.hash(), null, 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, source, null);
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}
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private void init(final byte[] urlhash, final String line, final int errorCode, final String errortext) {
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this.urlhash = urlhash;
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this.line = line;
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this.errorCode = errorCode;
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this.error = errortext;
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}
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public boolean exists() {
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return line != null;
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}
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public String getLineRaw() {
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return (line == null) ? "" : line;
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}
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public String getError() {
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return (error == null) ? "" : error.trim();
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}
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public int getErrorCode() {
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return errorCode;
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}
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public String getLineMarked(final HandleSet queryHashes) {
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if (line == null) return "";
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if (queryHashes == null || queryHashes.isEmpty()) return line.trim();
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if (line.endsWith(".")) line = line.substring(0, line.length() - 1);
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final Iterator<byte[]> i = queryHashes.iterator();
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byte[] h;
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final String[] words = line.split(" ");
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while (i.hasNext()) {
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h = i.next();
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for (int j = 0; j < words.length; j++) {
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final List<String> al = markedWordArrayList(words[j]); // mark special character separated words correctly if more than 1 word has to be marked
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words[j] = "";
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for (int k = 0; k < al.size(); k++) {
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if(k % 2 == 0){ // word has not been marked
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words[j] += getWordMarked(al.get(k), h);
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} else { // word has been marked, do not encode again
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words[j] += al.get(k);
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}
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}
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}
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}
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final StringBuilder l = new StringBuilder(line.length() + queryHashes.size() * 8);
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for (int j = 0; j < words.length; j++) {
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l.append(words[j]);
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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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public int compareTo(TextSnippet o) {
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return Base64Order.enhancedCoder.compare(this.urlhash, o.urlhash);
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}
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public int compare(TextSnippet o1, TextSnippet o2) {
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return o1.compareTo(o2);
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}
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@Override
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public int hashCode() {
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return ByteArray.hashCode(this.urlhash);
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}
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@Override
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public String toString() {
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return (line == null) ? "" : line;
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}
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/**
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* mark words with <b>-tags
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* @param word the word to mark
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* @param h the hash of the word to mark
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* @return the marked word if hash matches, else the unmarked word
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* @see #getLineMarked(Set)
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*/
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private static String getWordMarked(final String word, final byte[] h){
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//ignore punctuation marks (contrib [MN])
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//note to myself:
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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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StringBuilder theWord = new StringBuilder(word);
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StringBuilder prefix = new StringBuilder();
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StringBuilder postfix = new StringBuilder();
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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 = 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 = 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();
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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 (new String(Word.word2hash(temp)).equals(new String(h))) temp = "<b>" + CharacterCoding.unicode2html(temp, false) + "</b>";
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out.append(temp);
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out.append(CharacterCoding.unicode2html(theWord.substring(k,k+1), false));
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temp = "";
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}
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//last character
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else if(k == (theWord.length()-1)) {
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temp = temp + theWord.substring(k,k+1);
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if (new String(Word.word2hash(temp)).equals(new String(h))) temp = "<b>" + CharacterCoding.unicode2html(temp, false) + "</b>";
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out.append(temp);
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temp = "";
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}
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else {
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temp = temp + theWord.substring(k,k+1);
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}
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}
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theWord = out;
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}
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//end contrib [MN]
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else if (new String(Word.word2hash(theWord)).equals(new String(h))) {
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theWord.replace(0, theWord.length(), CharacterCoding.unicode2html(theWord.toString(), false));
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theWord.insert(0, "<b>");
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theWord.append("</b>");
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}
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theWord.insert(0, CharacterCoding.unicode2html(prefix.toString(), false));
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theWord.append(CharacterCoding.unicode2html(postfix.toString(), false));
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return theWord.toString();
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}
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/**
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* words that already has been marked has index <code>(i % 2 == 1)</code>
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* words that has not yet been marked has index <code>(i % 2 == 0)</code>
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* @param string the String to be processed
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* @return words that already has and has not yet been marked
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* @author [DW], 08.11.2008
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*/
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private static List<String> markedWordArrayList(String string){
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List<String> al = new java.util.ArrayList<String>(1);
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Matcher m = p01.matcher(string);
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while (m.find()) {
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al.add(m.group(1));
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al.add(m.group(2));
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string = m.group(3); // the postfix
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m = p01.matcher(string);
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}
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al.add(string);
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return al;
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}
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private static boolean containsAllHashes(final String sentence, final HandleSet queryhashes) {
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final SortedMap<byte[], Integer> m = Condenser.hashSentence(sentence, null);
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for (final byte[] b: queryhashes) {
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if (!(m.containsKey(b))) return false;
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}
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return true;
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}
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}
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