// AbstractCrawlWorker.java
// -------------------------------------
// part of YACY
// (C) by Michael Peter Christen; mc@anomic.de
// first published on http://www.anomic.de
// Frankfurt, Germany, 2006
//
// This file ist contributed by Martin Thelian
//
// $LastChangedDate: 2006-02-20 23:57:42 +0100 (Mo, 20 Feb 2006) $
// $LastChangedRevision: 1715 $
// $LastChangedBy: theli $
//
// 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
//
// Using this software in any meaning (reading, learning, copying, compiling,
// running) means that you agree that the Author(s) is (are) not responsible
// for cost, loss of data or any harm that may be caused directly or indirectly
// by usage of this softare or this documentation. The usage of this software
// is on your own risk. The installation and usage (starting/running) of this
// software may allow other people or application to access your computer and
// any attached devices and is highly dependent on the configuration of the
// software which must be done by the user of the software; the author(s) is
// (are) also not responsible for proper configuration and usage of the
// software, even if provoked by documentation provided together with
// the software.
//
// Any changes to this file according to the GPL as documented in the file
// gpl.txt aside this file in the shipment you received can be done to the
// lines that follows this copyright notice here, but changes must not be
// done inside the copyright notive above. A re-distribution must contain
// the intact and unchanged copyright notice.
// Contributions and changes to the program code must be marked as such.
package de.anomic.plasma.crawler;
import java.io.File;
import java.io.IOException;
import de.anomic.plasma.plasmaURL;
import de.anomic.net.URL;
import de.anomic.plasma.plasmaCrawlEntry;
import de.anomic.plasma.plasmaCrawlLoaderMessage;
import de.anomic.plasma.plasmaCrawlProfile;
import de.anomic.plasma.plasmaCrawlZURL;
import de.anomic.plasma.plasmaHTCache;
import de.anomic.plasma.plasmaSwitchboard;
import de.anomic.server.logging.serverLog;
import de.anomic.yacy.yacyCore;
public abstract class AbstractCrawlWorker extends Thread implements plasmaCrawlWorker {
/**
* The protocol that is supported by this crawler
* e.g. http, ftp, etc.
*/
protected String protocol;
/* ============================================================
* Variables for thread pool management
* ============================================================ */
public boolean destroyed = false;
protected boolean running = false;
protected boolean stopped = false;
/**
* Specifies that the execution of the current crawl job has finished
*/
protected boolean done = false;
/* ============================================================
* Crawl job specific variables
* ============================================================ */
public plasmaCrawlLoaderMessage theMsg;
protected URL url;
protected String name;
protected String refererURLString;
protected String initiator;
protected int depth;
protected long startdate;
protected plasmaCrawlProfile.entry profile;
protected boolean acceptAllContent;
protected boolean keepInMemory;
protected String errorMessage;
/**
* The crawler thread pool
*/
protected final plasmaCrawlerPool myPool;
/**
* reference to the plasma switchboard
*/
protected final plasmaSwitchboard sb;
/**
* reference to the cache manager
*/
protected final plasmaHTCache cacheManager;
/**
* Logging class
*/
protected final serverLog log;
/**
* Constructor of this class
* @param theTG the crawl worker thread group
* @param thePool the crawl worker thread pool
* @param theSb plasma switchboard
* @param theCacheManager cache manager
* @param theLog server log
*/
public AbstractCrawlWorker(
ThreadGroup theTG,
plasmaCrawlerPool thePool,
plasmaSwitchboard theSb,
plasmaHTCache theCacheManager,
serverLog theLog
) {
super(theTG,plasmaCrawlWorker.threadBaseName + "_created");
this.myPool = thePool;
this.sb = theSb;
this.cacheManager = theCacheManager;
this.log = theLog;
}
public void setNameTrailer(String trailer) {
this.setName(plasmaCrawlWorker.threadBaseName + trailer);
}
public plasmaCrawlLoaderMessage getMessage() {
return this.theMsg;
}
public abstract void close();
public long getDuration() {
final long startDate = this.startdate;
return (startDate != 0) ? System.currentTimeMillis() - startDate : 0;
}
public void run() {
this.running = true;
try {
// The thread keeps running.
while (!this.stopped && !this.isInterrupted()) {
if (this.done) {
if (this.myPool != null && !this.myPool.isClosed) {
synchronized (this) {
// return thread back into pool
this.myPool.returnObject(this.protocol,this);
// We are waiting for a new task now.
if (!this.stopped && !this.destroyed && !this.isInterrupted()) {
this.wait();
}
}
} else {
this.stopped = true;
}
} else {
try {
// executing the new task
execute();
} finally {
// free memory
reset();
}
}
}
} catch (InterruptedException ex) {
serverLog.logFiner("CRAWLER-POOL","Interruption of thread '" + this.getName() + "' detected.");
} finally {
if (this.myPool != null && !this.destroyed)
this.myPool.invalidateObject(this.protocol,this);
}
}
public void execute() {
plasmaHTCache.Entry loadedResource = null;
try {
// setting threadname
this.setName(plasmaCrawlWorker.threadBaseName + "_" + this.url);
// load some configuration variables
init();
// loading resource
loadedResource = load();
} catch (IOException e) {
//throw e;
} finally {
// setting the error message (if available)
if (this.errorMessage != null) {
this.theMsg.setError(this.errorMessage);
}
// store a reference to the result in the message object
// this is e.g. needed by the snippet fetcher
//
// Note: this is always called, even on empty results.
// Otherwise the caller will block forever
this.theMsg.setResult(loadedResource);
// signal that this worker thread has finished the job
this.done = true;
}
}
public void execute(plasmaCrawlLoaderMessage theNewMsg) {
synchronized (this) {
this.theMsg = theNewMsg;
this.url = theNewMsg.url;
this.name = theNewMsg.name;
this.refererURLString = theNewMsg.referer;
this.initiator = theNewMsg.initiator;
this.depth = theNewMsg.depth;
this.profile = theNewMsg.profile;
this.acceptAllContent = theNewMsg.acceptAllContent;
this.keepInMemory = theNewMsg.keepInMemory;
this.startdate = System.currentTimeMillis();
this.done = false;
if (!this.running) {
// if the thread is not running until yet, we need to start it now
this.start();
} else {
// inform the thread about the new crawl job
this.notifyAll();
}
}
}
public void setStopped(boolean isStopped) {
this.stopped = isStopped;
}
public void setDestroyed(boolean isDestroyed) {
this.destroyed = isDestroyed;
}
public boolean isRunning() {
return this.running;
}
public void reset() {
this.theMsg = null;
this.url = null;
this.name = null;
this.refererURLString = null;
this.initiator = null;
this.depth = 0;
this.startdate = 0;
this.profile = null;
this.acceptAllContent = false;
this.keepInMemory = false;
this.errorMessage = null;
}
protected void addURLtoErrorDB(String failreason) {
// remember error message
this.errorMessage = failreason;
// convert the referrer URL into a hash value
String referrerHash = (this.refererURLString==null)?null:plasmaURL.urlHash(this.refererURLString);
// create a new errorURL DB entry
plasmaCrawlEntry bentry = new plasmaCrawlEntry(
this.initiator,
this.url,
referrerHash,
this.name,
null,
this.profile.handle(),
this.depth,
0,
0);
plasmaCrawlZURL.Entry ee = this.sb.errorURL.newEntry(
bentry, yacyCore.seedDB.mySeed.hash, null,
0, (failreason==null)?"Unknown reason":failreason);
// store the entry
ee.store();
// push it onto the stack
this.sb.errorURL.stackPushEntry(ee);
// delete the cache file
File cacheFile = this.cacheManager.getCachePath(this.url);
if (cacheFile.exists()) cacheFile.delete();
}
}