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// NoticedURL.java
// -----------------------
// part of YaCy
// (C) by Michael Peter Christen; mc@yacy.net
// first published on http://www.anomic.de
// Frankfurt, Germany, 2004
//
//$LastChangedDate$
//$LastChangedRevision$
//$LastChangedBy$
//
// 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
// NURL - noticed (known but not loaded) URL's
package net.yacy.crawler.data;
import java.io.File;
import java.io.IOException;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import net.yacy.cora.order.Base64Order;
import net.yacy.cora.storage.HandleSet;
import net.yacy.cora.util.ConcurrentLog;
import net.yacy.cora.util.SpaceExceededException;
import net.yacy.crawler.Balancer;
import net.yacy.crawler.CrawlSwitchboard;
import net.yacy.crawler.HostBalancer;
import net.yacy.crawler.retrieval.Request;
import net.yacy.crawler.robots.RobotsTxt;
import net.yacy.kelondro.data.word.Word;
import net.yacy.kelondro.index.RowHandleSet;
import net.yacy.kelondro.util.MemoryControl;
public class NoticedURL {
public enum StackType {
LOCAL, GLOBAL, REMOTE, NOLOAD;
}
/** links found by crawling to depth-1 */
private Balancer coreStack;
/** links found by crawling at target depth */
private Balancer limitStack;
/** links from remote crawl orders (init on demand) */
private Balancer remoteStack;
/** links that are not passed to a loader; the index will be generated from the Request entry */
private Balancer noloadStack;
private final File cachePath;
protected NoticedURL(
final File cachePath,
final int onDemandLimit,
final boolean exceed134217727) {
ConcurrentLog.info("NoticedURL", "START CREATING STACKS at " + cachePath.toString());
ConcurrentLog.info("NoticedURL", "opening CrawlerCoreStacks..");
this.cachePath = cachePath;
this.coreStack = new HostBalancer(new File(cachePath, "CrawlerCoreStacks"), onDemandLimit, exceed134217727);
ConcurrentLog.info("NoticedURL", "opening CrawlerLimitStacks..");
this.limitStack = new HostBalancer(new File(cachePath, "CrawlerLimitStacks"), onDemandLimit, exceed134217727);
this.remoteStack = null; // init on demand (on first push)
ConcurrentLog.info("NoticedURL", "opening CrawlerNoLoadStacks..");
this.noloadStack = new HostBalancer(new File(cachePath, "CrawlerNoLoadStacks"), onDemandLimit, exceed134217727);
ConcurrentLog.info("NoticedURL", "FINISHED CREATING STACKS at " + cachePath.toString());
}
/**
* Init Remote crawl stack, internally called on 1st push to remoteStack
*/
protected void initRemoteStack() {
if (this.remoteStack == null && !MemoryControl.shortStatus()) {
ConcurrentLog.info("NoticedURL", "opening CrawlerRemoteStacks..");
this.remoteStack = new HostBalancer(new File(this.cachePath, "CrawlerRemoteStacks"), this.coreStack.getOnDemandLimit(), this.coreStack.getExceed134217727());
}
}
public void clear() {
ConcurrentLog.info("NoticedURL", "CLEARING ALL STACKS");
if (this.coreStack != null) this.coreStack.clear();
if (this.limitStack != null) this.limitStack.clear();
if (this.remoteStack != null) this.remoteStack.clear();
if (this.noloadStack != null) this.noloadStack.clear();
}
protected void close() {
ConcurrentLog.info("NoticedURL", "CLOSING ALL STACKS");
if (this.coreStack != null) {
this.coreStack.close();
this.coreStack = null;
}
if (this.limitStack != null) {
this.limitStack.close();
this.limitStack = null;
}
//overhangStack.close();
if (this.remoteStack != null) {
this.remoteStack.close();
this.remoteStack = null;
}
if (this.noloadStack != null) {
this.noloadStack.close();
this.noloadStack = null;
}
}
@Override
protected void finalize() throws Throwable {
if ((this.coreStack != null) || (this.limitStack != null) || (this.remoteStack != null)) {
ConcurrentLog.warn("plasmaCrawlNURL", "NURL stack closed by finalizer");
close();
}
super.finalize();
}
public int size() {
return ((this.coreStack == null) ? 0 : this.coreStack.size()) + ((this.limitStack == null) ? 0 : this.limitStack.size()) + ((this.remoteStack == null) ? 0 : this.remoteStack.size());
}
public boolean isEmptyLocal() {
if (this.coreStack == null) return true;
if (!this.coreStack.isEmpty()) return false;
if (!this.limitStack.isEmpty()) return false;
if (!this.noloadStack.isEmpty()) return false;
return true;
}
public boolean isEmpty() {
if (!isEmptyLocal()) return false;
if (this.remoteStack != null && !this.remoteStack.isEmpty()) return false;
return true;
}
public boolean isEmpty(final StackType stackType) {
switch (stackType) {
case NOLOAD: return (this.noloadStack == null) ? true : this.noloadStack.isEmpty();
case LOCAL: return (this.coreStack == null) ? true : this.coreStack.isEmpty();
case GLOBAL: return (this.limitStack == null) ? true : this.limitStack.isEmpty();
case REMOTE: return (this.remoteStack == null) ? true : this.remoteStack.isEmpty();
default: return true;
}
}
public int stackSize(final StackType stackType) {
switch (stackType) {
case NOLOAD: return (this.noloadStack == null) ? 0 : this.noloadStack.size();
case LOCAL: return (this.coreStack == null) ? 0 : this.coreStack.size();
case GLOBAL: return (this.limitStack == null) ? 0 : this.limitStack.size();
case REMOTE: return (this.remoteStack == null) ? 0 : this.remoteStack.size();
default: return -1;
}
}
protected boolean existsInStack(final byte[] urlhashb) {
return
this.coreStack.has(urlhashb) ||
this.limitStack.has(urlhashb) ||
(this.remoteStack != null && this.remoteStack.has(urlhashb)) ||
this.noloadStack.has(urlhashb);
}
/**
* push a crawl request on one of the different crawl stacks
* @param stackType
* @param entry
* @return null if this was successful or a String explaining what went wrong in case of an error
*/
public String push(final StackType stackType, final Request entry, CrawlProfile profile, final RobotsTxt robots) {
try {
switch (stackType) {
case LOCAL: return this.coreStack.push(entry, profile, robots);
case GLOBAL: return this.limitStack.push(entry, profile, robots);
case REMOTE: {
if (this.remoteStack == null) {
this.initRemoteStack();
}
return (this.remoteStack != null) ? this.remoteStack.push(entry, profile, robots) : "remote crawler stack deactivated";
}
case NOLOAD: return this.noloadStack.push(entry, profile, robots);
default: return "stack type unknown";
}
} catch (final Exception er) {
ConcurrentLog.logException(er);
return "error pushing onto the crawl stack: " + er.getMessage();
}
}
protected Request get(final byte[] urlhash) {
Request entry = null;
try {if ((entry = this.noloadStack.get(urlhash)) != null) return entry;} catch (final IOException e) {}
try {if ((entry = this.coreStack.get(urlhash)) != null) return entry;} catch (final IOException e) {}
try {if ((entry = this.limitStack.get(urlhash)) != null) return entry;} catch (final IOException e) {}
try {if (this.remoteStack != null && (entry = this.remoteStack.get(urlhash)) != null) return entry;} catch (final IOException e) {}
return null;
}
/**
* remove a CrawlEntry by a given hash. Usage of this method is not encouraged,
* because the underlying data structure (crawl stacks) cannot handle removals very good.
* @param urlhash
* @return true, if the entry was removed; false if not
*/
public boolean removeByURLHash(final byte[] urlhashBytes) {
try {
final HandleSet urlHashes = new RowHandleSet(Word.commonHashLength, Base64Order.enhancedCoder, 1);
urlHashes.put(urlhashBytes);
boolean ret = false;
try {ret |= this.noloadStack.remove(urlHashes) > 0;} catch (final IOException e) {}
try {ret |= this.coreStack.remove(urlHashes) > 0;} catch (final IOException e) {}
try {ret |= this.limitStack.remove(urlHashes) > 0;} catch (final IOException e) {}
try {ret |= this.remoteStack != null && this.remoteStack.remove(urlHashes) > 0;} catch (final IOException e) {}
return ret;
} catch (final SpaceExceededException e) {
ConcurrentLog.logException(e);
return false;
}
}
public int removeByProfileHandle(final String handle, final long timeout) throws SpaceExceededException {
int removed = 0;
try {removed += this.noloadStack.removeAllByProfileHandle(handle, timeout);} catch (final IOException e) {}
try {removed += this.coreStack.removeAllByProfileHandle(handle, timeout);} catch (final IOException e) {}
try {removed += this.limitStack.removeAllByProfileHandle(handle, timeout);} catch (final IOException e) {}
if (this.remoteStack != null) try {removed += this.remoteStack.removeAllByProfileHandle(handle, timeout);} catch (final IOException e) {}
return removed;
}
public int removeByHostHash(final Set<String> hosthashes) {
int removed = 0;
removed += this.noloadStack.removeAllByHostHashes(hosthashes);
removed += this.coreStack.removeAllByHostHashes(hosthashes);
removed += this.limitStack.removeAllByHostHashes(hosthashes);
if (this.remoteStack != null) removed += this.remoteStack.removeAllByHostHashes(hosthashes);
return removed;
}
/**
* get a list of domains that are currently maintained as domain stacks
* @return a map of clear text strings of host names (each host name eventually concatenated with a port, depending on the stack) to two integers: the size of the domain stacks and the access delta time
*/
public Map<String, Integer[]> getDomainStackHosts(final StackType stackType, RobotsTxt robots) {
switch (stackType) {
case LOCAL: return this.coreStack.getDomainStackHosts(robots);
case GLOBAL: return this.limitStack.getDomainStackHosts(robots);
case REMOTE: return (this.remoteStack != null) ? this.remoteStack.getDomainStackHosts(robots) : null;
case NOLOAD: return this.noloadStack.getDomainStackHosts(robots);
default: return null;
}
}
/**
* get lists of crawl request entries for a specific host
* @param host
* @param maxcount
* @return a list of crawl loader requests
*/
public List<Request> getDomainStackReferences(final StackType stackType, String host, int maxcount, final long maxtime) {
switch (stackType) {
case LOCAL: return this.coreStack.getDomainStackReferences(host, maxcount, maxtime);
case GLOBAL: return this.limitStack.getDomainStackReferences(host, maxcount, maxtime);
case REMOTE: return (this.remoteStack != null) ? this.remoteStack.getDomainStackReferences(host, maxcount, maxtime) : Collections.emptyList();
case NOLOAD: return this.noloadStack.getDomainStackReferences(host, maxcount, maxtime);
default: return Collections.emptyList();
}
}
public Request pop(final StackType stackType, final boolean delay, final CrawlSwitchboard cs, final RobotsTxt robots) throws IOException {
switch (stackType) {
case LOCAL: return pop(this.coreStack, delay, cs, robots);
case GLOBAL: return pop(this.limitStack, delay, cs, robots);
case REMOTE: return (this.remoteStack != null) ? pop(this.remoteStack, delay, cs, robots) : null;
case NOLOAD: return pop(this.noloadStack, false, cs, robots);
default: return null;
}
}
protected void shift(final StackType fromStack, final StackType toStack, final CrawlSwitchboard cs, final RobotsTxt robots) {
try {
final Request entry = pop(fromStack, false, cs, robots);
if (entry != null) {
final String warning = push(toStack, entry, null, robots);
if (warning != null) {
ConcurrentLog.warn("NoticedURL", "shift from " + fromStack + " to " + toStack + ": " + warning);
}
}
} catch (final IOException e) {
return;
}
}
public void clear(final StackType stackType) {
ConcurrentLog.info("NoticedURL", "CLEARING STACK " + stackType);
switch (stackType) {
case LOCAL:
this.coreStack.clear();
break;
case GLOBAL:
this.limitStack.clear();
break;
case REMOTE:
if (this.remoteStack != null) {
this.remoteStack.clear();
}
break;
case NOLOAD:
this.noloadStack.clear();
break;
default:
return;
}
}
private static Request pop(final Balancer balancer, final boolean delay, final CrawlSwitchboard cs, final RobotsTxt robots) throws IOException {
// this is a filo - pop
int s;
Request entry;
int errors = 0;
while (!balancer.isEmpty()) {
entry = balancer.pop(delay, cs, robots);
if (entry != null) return entry;
// the balancer was supposed to be not empty. Check this again
// it may be possible that another process has taken all
s = balancer.size(); // this time read the size to find errors
if (s == 0) return null; // the balancer is actually empty!
// if the balancer is not empty, try again
entry = balancer.pop(delay, cs, robots);
if (entry != null) return entry;
if (s > balancer.size()) continue; // the balancer has shrinked, thats good, it will terminate
errors++; // bad, if the size does not shrink we are in danger to not terminate
if (errors < 100) continue; // there is the possibility that it is not a bug but concurrency, so just ignore it for some time
// at this point we consider the balancer to be broken
final int aftersize = balancer.size(); // get the amount of data that we loose
balancer.clear(); // the balancer is broken and cannot shrink
ConcurrentLog.warn("BALANCER", "balancer cannot shrink (bevore pop = " + s + ", after pop = " + aftersize + "); reset of balancer");
return null;
}
return null;
}
public Iterator<Request> iterator(final StackType stackType) {
// returns an iterator of plasmaCrawlBalancerEntry Objects
try {switch (stackType) {
case LOCAL: return this.coreStack.iterator();
case GLOBAL: return this.limitStack.iterator();
case REMOTE: return (this.remoteStack != null) ? this.remoteStack.iterator() : null;
case NOLOAD: return this.noloadStack.iterator();
default: return null;
}} catch (final IOException e) {
return new HashSet<Request>().iterator();
}
}
}
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