You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
221 lines
8.2 KiB
221 lines
8.2 KiB
// plasmaCrawlBalancer.java
|
|
// -----------------------
|
|
// part of YaCy
|
|
// (C) by Michael Peter Christen; mc@anomic.de
|
|
// first published on http://www.anomic.de
|
|
// Frankfurt, Germany, 2005
|
|
// created: 24.09.2005
|
|
//
|
|
// 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;
|
|
|
|
import java.io.File;
|
|
import java.io.IOException;
|
|
import java.util.ArrayList;
|
|
import java.util.HashMap;
|
|
import java.util.Iterator;
|
|
import java.util.Map;
|
|
|
|
import de.anomic.kelondro.kelondroBase64Order;
|
|
import de.anomic.kelondro.kelondroRecords;
|
|
import de.anomic.kelondro.kelondroRow;
|
|
import de.anomic.kelondro.kelondroStack;
|
|
import de.anomic.yacy.yacySeedDB;
|
|
|
|
public class plasmaCrawlBalancer {
|
|
|
|
private kelondroStack stack;
|
|
private HashMap domainStacks;
|
|
private HashMap domainAccess;
|
|
|
|
public plasmaCrawlBalancer(File stackFile) {
|
|
stack = kelondroStack.open(stackFile, new kelondroRow("byte[] urlhash-" + yacySeedDB.commonHashLength, kelondroBase64Order.enhancedCoder, 0));
|
|
domainStacks = new HashMap();
|
|
domainAccess = new HashMap();
|
|
}
|
|
|
|
public void close() {
|
|
try { flushSome(domainStacks.size()); } catch (IOException e) {}
|
|
try { stack.close(); } catch (IOException e) {}
|
|
stack = null;
|
|
}
|
|
|
|
public void reset() {
|
|
synchronized (domainStacks) {
|
|
stack = kelondroStack.reset(stack);
|
|
domainStacks.clear();
|
|
}
|
|
}
|
|
|
|
public Iterator iterator() {
|
|
// iterates byte[] - objects
|
|
return new KeyIterator(stack.iterator());
|
|
}
|
|
|
|
public int size() {
|
|
return stack.size() + sizeDomainStacks();
|
|
}
|
|
|
|
private int sizeDomainStacks() {
|
|
if (domainStacks == null) return 0;
|
|
int sum = 0;
|
|
synchronized (domainStacks) {
|
|
Iterator i = domainStacks.values().iterator();
|
|
while (i.hasNext()) sum += ((ArrayList) i.next()).size();
|
|
}
|
|
return sum;
|
|
}
|
|
|
|
private void flushOnce() throws IOException {
|
|
// takes one entry from every domain stack and puts it on the file stack
|
|
synchronized (domainStacks) {
|
|
Iterator i = domainStacks.entrySet().iterator();
|
|
Map.Entry entry;
|
|
ArrayList list;
|
|
while (i.hasNext()) {
|
|
entry = (Map.Entry) i.next();
|
|
list = (ArrayList) entry.getValue();
|
|
if (list.size() != 0) {
|
|
stack.push(stack.row().newEntry(new byte[][]{(byte[]) list.remove(0)}));
|
|
}
|
|
if (list.size() == 0) i.remove();
|
|
}
|
|
}
|
|
}
|
|
|
|
private void flushSome(int count) throws IOException {
|
|
while ((domainStacks.size() > 0) && (count-- > 0)) flushOnce();
|
|
}
|
|
|
|
public void add(String domain, byte[] hash) throws IOException {
|
|
synchronized (domainStacks) {
|
|
ArrayList domainList = (ArrayList) domainStacks.get(domain);
|
|
if (domainList == null) {
|
|
// create new list
|
|
domainList = new ArrayList();
|
|
domainList.add(hash);
|
|
domainStacks.put(domain, domainList);
|
|
} else {
|
|
// extend existent domain list
|
|
domainList.add(hash);
|
|
}
|
|
}
|
|
|
|
// check size of domainStacks and flush
|
|
if ((domainStacks.size() > 20) || (sizeDomainStacks() > 400)) {
|
|
flushOnce();
|
|
}
|
|
}
|
|
|
|
public String get(long minimumDelta) throws IOException {
|
|
// returns an url-hash from the stack and ensures minimum delta times
|
|
synchronized (domainStacks) {
|
|
if ((stack.size() == 0) && (domainStacks.size() > 0)) flushOnce();
|
|
if (stack.size() == 0) return null;
|
|
|
|
String entry = null;
|
|
kelondroRow.Entry topentry = stack.top();
|
|
if (topentry == null) return null;
|
|
String top = new String(topentry.getColBytes(0));
|
|
|
|
// check if the time after retrieval of last hash from same
|
|
// domain is not shorter than the minimumDelta
|
|
long delta = lastAccessDelta(top);
|
|
if (delta > minimumDelta) {
|
|
// the entry from top is fine
|
|
entry = new String(stack.pop().getColBytes(0));
|
|
} else {
|
|
// try entry from bottom
|
|
entry = new String(stack.pot().getColBytes(0));
|
|
delta = lastAccessDelta(entry);
|
|
}
|
|
|
|
if (delta < minimumDelta) {
|
|
// force a busy waiting here
|
|
// in best case, this should never happen if the balancer works propertly
|
|
// this is only to protect against the worst case, where the crawler could
|
|
// behave in a DoS-manner
|
|
long sleeptime = minimumDelta - delta;
|
|
try {synchronized(this) { this.wait(sleeptime); }} catch (InterruptedException e) {}
|
|
}
|
|
domainAccess.put(entry.substring(6), new Long(System.currentTimeMillis()));
|
|
return entry;
|
|
}
|
|
}
|
|
|
|
private long lastAccessDelta(String urlhash) {
|
|
assert urlhash != null;
|
|
Long lastAccess = (Long) domainAccess.get(urlhash.substring(6));
|
|
if (lastAccess == null) return Long.MAX_VALUE; // never accessed
|
|
return System.currentTimeMillis() - lastAccess.longValue();
|
|
}
|
|
|
|
public byte[] top(int dist) throws IOException {
|
|
flushSome(1 + dist - stack.size()); // flush only that much as we need to display
|
|
synchronized (domainStacks) {
|
|
return stack.top(dist).getColBytes(0);
|
|
}
|
|
}
|
|
|
|
public void clear() throws IOException {
|
|
synchronized (domainStacks) {
|
|
domainStacks.clear();
|
|
stack = kelondroStack.reset(stack);
|
|
}
|
|
}
|
|
|
|
public class KeyIterator implements Iterator {
|
|
|
|
Iterator ni;
|
|
|
|
public KeyIterator(Iterator i) {
|
|
ni = i;
|
|
}
|
|
|
|
public boolean hasNext() {
|
|
return ni.hasNext();
|
|
}
|
|
|
|
public Object next() {
|
|
return ((kelondroRecords.Node) ni.next()).getKey();
|
|
}
|
|
|
|
public void remove() {
|
|
}
|
|
|
|
}
|
|
|
|
}
|