bdbfrontier.java

高性能分词算法

/* BdbFrontier
 * 
 * $Id: BdbFrontier.java 5440 2007-08-28 05:19:52Z gojomo $
* 
 * Created on Sep 24, 2004
 *
 *  Copyright (C) 2004 Internet Archive.
 *
 * This file is part of the Heritrix web crawler (crawler.archive.org).
 *
 * Heritrix is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * any later version.
 *
 * Heritrix 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 Lesser Public License for more details.
 *
 * You should have received a copy of the GNU Lesser Public License
 * along with Heritrix; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
  */
package org.archive.crawler.frontier;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Queue;
import java.util.TreeSet;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.management.AttributeNotFoundException;

import org.apache.commons.collections.Closure;
import org.archive.crawler.datamodel.CrawlURI;
import org.archive.crawler.datamodel.UriUniqFilter;
import org.archive.crawler.framework.CrawlController;
import org.archive.crawler.framework.FrontierMarker;
import org.archive.crawler.framework.exceptions.FatalConfigurationException;
import org.archive.crawler.settings.SimpleType;
import org.archive.crawler.settings.Type;
import org.archive.crawler.util.BdbUriUniqFilter;
import org.archive.crawler.util.BloomUriUniqFilter;
import org.archive.crawler.util.CheckpointUtils;
import org.archive.crawler.util.DiskFPMergeUriUniqFilter;
import org.archive.crawler.util.MemFPMergeUriUniqFilter;
import org.archive.queue.StoredQueue;
import org.archive.util.ArchiveUtils;

import com.sleepycat.je.Database;
import com.sleepycat.je.DatabaseException;

/**
 * A Frontier using several BerkeleyDB JE Databases to hold its record of
 * known hosts (queues), and pending URIs. 
 *
 * @author Gordon Mohr
 */
public class BdbFrontier extends WorkQueueFrontier implements Serializable {
    // be robust against trivial implementation changes
    private static final long serialVersionUID = ArchiveUtils
        .classnameBasedUID(BdbFrontier.class, 1);

    private static final Logger logger =
        Logger.getLogger(BdbFrontier.class.getName());

    /** all URIs scheduled to be crawled */
    protected transient BdbMultipleWorkQueues pendingUris;

    /** all URI-already-included options available to be chosen */
    private String[] AVAILABLE_INCLUDED_OPTIONS = new String[] {
            BdbUriUniqFilter.class.getName(),
            BloomUriUniqFilter.class.getName(),
            MemFPMergeUriUniqFilter.class.getName(),
            DiskFPMergeUriUniqFilter.class.getName()};
    
    /** URI-already-included to use (by class name) */
    public final static String ATTR_INCLUDED = "uri-included-structure";
    
    private final static String DEFAULT_INCLUDED =
        BdbUriUniqFilter.class.getName();
    
    /** URI-already-included to use (by class name) */
    public final static String ATTR_DUMP_PENDING_AT_CLOSE = 
        "dump-pending-at-close";
    private final static Boolean DEFAULT_DUMP_PENDING_AT_CLOSE = 
        Boolean.FALSE;

    
    /**
     * Constructor.
     * @param name Name for of this Frontier.
     */
    public BdbFrontier(String name) {
        this(name, "BdbFrontier. "
            + "A Frontier using BerkeleyDB Java Edition databases for "
            + "persistence to disk.");
        Type t = addElementToDefinition(new SimpleType(ATTR_INCLUDED,
                "Structure to use for tracking already-seen URIs. Non-default " +
                "options may require additional configuration via system " +
                "properties.", DEFAULT_INCLUDED, AVAILABLE_INCLUDED_OPTIONS));
        t.setExpertSetting(true);
        t = addElementToDefinition(new SimpleType(ATTR_DUMP_PENDING_AT_CLOSE,
                "Whether to dump all URIs waiting in queues to crawl.log " +
                "when a crawl ends. May add a significant delay to " +
                "crawl termination. Dumped lines will have a zero (0) " +
                "status.", DEFAULT_DUMP_PENDING_AT_CLOSE));
        t.setExpertSetting(true);
    }

    /**
     * Create the BdbFrontier
     * 
     * @param name
     * @param description
     */
    public BdbFrontier(String name, String description) {
        super(name, description);
    }
    
    /**
     * Create the single object (within which is one BDB database)
     * inside which all the other queues live. 
     * 
     * @return the created BdbMultipleWorkQueues
     * @throws DatabaseException
     */
    private BdbMultipleWorkQueues createMultipleWorkQueues()
    throws DatabaseException {
        return new BdbMultipleWorkQueues(this.controller.getBdbEnvironment(),
            this.controller.getBdbEnvironment().getClassCatalog(),
            this.controller.isCheckpointRecover());
    }

    
    @Override
    protected void initQueuesOfQueues() {
        if(this.controller.isCheckpointRecover()) {
            // do not setup here; take/init from deserialized frontier
            return; 
        }
        // small risk of OutOfMemoryError: if 'hold-queues' is false,
        // readyClassQueues may grow in size without bound
        readyClassQueues = new LinkedBlockingQueue<String>();

        try {
            Database inactiveQueuesDb = this.controller.getBdbEnvironment()
                    .openDatabase(null, "inactiveQueues",
                            StoredQueue.databaseConfig());
            inactiveQueues = new StoredQueue<String>(inactiveQueuesDb,
                    String.class, null);
            Database retiredQueuesDb = this.controller.getBdbEnvironment()
                    .openDatabase(null, "retiredQueues",
                            StoredQueue.databaseConfig());
            retiredQueues = new StoredQueue<String>(retiredQueuesDb,
                    String.class, null);
        } catch (DatabaseException e) {
            throw new RuntimeException(e);
        }
        
        // small risk of OutOfMemoryError: in large crawls with many 
        // unresponsive queues, an unbounded number of snoozed queues 
        // may exist
        snoozedClassQueues = Collections.synchronizedSortedSet(new TreeSet<WorkQueue>());
    }

    protected Queue<String> reinit(Queue<String> q, String name) {
        try {
            // restore the innner Database/StoredSortedMap of the queue
            Database db = this.controller.getBdbEnvironment()
                .openDatabase(null, name, StoredQueue.databaseConfig());
            
            StoredQueue<String> queue;
            if(q instanceof StoredQueue) {
                queue = (StoredQueue<String>) q;
                queue.hookupDatabase(db, String.class, null);
            } else {
                // recovery of older checkpoint; copy to StoredQueue
                queue = new StoredQueue<String>(db,String.class,
                        this.controller.getBdbEnvironment().getClassCatalog()); 
                queue.addAll(q);
            }
            return queue;
        } catch (DatabaseException e) {
            throw new RuntimeException(e);
        }
    }
    
    /**
     * Create a UriUniqFilter that will serve as record 
     * of already seen URIs.
     *
     * @return A UURISet that will serve as a record of already seen URIs
     * @throws IOException
     */
    protected UriUniqFilter createAlreadyIncluded() throws IOException {
        UriUniqFilter uuf;
        String c = null;
        try {
            c = (String)getAttribute(null, ATTR_INCLUDED);
        } catch (AttributeNotFoundException e) {
            // Do default action if attribute not in order.
        }
        // TODO: avoid all this special-casing; enable some common
        // constructor interface usable for all alt implemenations
        if (c != null && c.equals(BloomUriUniqFilter.class.getName())) {
            uuf = this.controller.isCheckpointRecover()?
                    deserializeAlreadySeen(BloomUriUniqFilter.class,
                        this.controller.getCheckpointRecover().getDirectory()):
                    new BloomUriUniqFilter();
        } else if (c!=null && c.equals(MemFPMergeUriUniqFilter.class.getName())) {
            // TODO: add checkpointing for MemFPMergeUriUniqFilter
            uuf = new MemFPMergeUriUniqFilter();
        } else if (c!=null && c.equals(DiskFPMergeUriUniqFilter.class.getName())) {
            // TODO: add checkpointing for DiskFPMergeUriUniqFilter
            uuf = new DiskFPMergeUriUniqFilter(controller.getScratchDisk());
        } else {