// plasmaCrawlLURL.java
// -----------------------
// part of YaCy
// (C) by Michael Peter Christen; mc@yacy.net
// first published on http://yacy.net
// Frankfurt, Germany, 2004
//
// $LastChangedDate: 2008-03-16 23:31:54 +0100 (So, 16 Mrz 2008) $
// $LastChangedRevision: 4575 $
// $LastChangedBy: orbiter $
//
// 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
/*
This class provides storage functions for the plasma search engine.
- the url-specific properties, including condenser results
- the text content of the url
Both entities are accessed with a hash, which is based on the MD5
algorithm. The MD5 is not encoded as a hex value, but a b64 value.
*/
package de.anomic.crawler;
import java.net.MalformedURLException;
import java.util.Date;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import de.anomic.kelondro.order.Bitfield;
import de.anomic.kelondro.text.metadataPrototype.URLMetadataRow;
import de.anomic.kelondro.util.ScoreCluster;
import de.anomic.yacy.yacySeedDB;
import de.anomic.yacy.yacyURL;
import de.anomic.yacy.logging.Log;
public final class ResultURLs {
// result stacks;
// these have all entries of form
// strings: urlHash + initiatorHash + ExecutorHash
private final LinkedList<String> externResultStack; // 1 - remote index: retrieved by other peer
private final LinkedList<String> searchResultStack; // 2 - partly remote/local index: result of search queries
private final LinkedList<String> transfResultStack; // 3 - partly remote/local index: result of index transfer
private final LinkedList<String> proxyResultStack; // 4 - local index: result of proxy fetch/prefetch
private final LinkedList<String> lcrawlResultStack; // 5 - local index: result of local crawling
private final LinkedList<String> gcrawlResultStack; // 6 - local index: triggered external
private final ScoreCluster<String> externResultDomains;
private final ScoreCluster<String> searchResultDomains;
private final ScoreCluster<String> transfResultDomains;
private final ScoreCluster<String> proxyResultDomains;
private final ScoreCluster<String> lcrawlResultDomains;
private final ScoreCluster<String> gcrawlResultDomains;
public ResultURLs() {
// init result stacks
externResultStack = new LinkedList<String>();
searchResultStack = new LinkedList<String>();
transfResultStack = new LinkedList<String>();
proxyResultStack = new LinkedList<String>();
lcrawlResultStack = new LinkedList<String>();
gcrawlResultStack = new LinkedList<String>();
// init result domain statistics
externResultDomains = new ScoreCluster<String>();
searchResultDomains = new ScoreCluster<String>();
transfResultDomains = new ScoreCluster<String>();
proxyResultDomains = new ScoreCluster<String>();
lcrawlResultDomains = new ScoreCluster<String>();
gcrawlResultDomains = new ScoreCluster<String>();
}
public synchronized void stack(final URLMetadataRow e, final String initiatorHash, final String executorHash, final int stackType) {
assert initiatorHash != null;
assert executorHash != null;
if (e == null) { return; }
try {
final List<String> resultStack = getStack(stackType);
if (resultStack != null) {
resultStack.add(e.hash() + initiatorHash + executorHash);
}
} catch (final Exception ex) {
System.out.println("INTERNAL ERROR in newEntry/2: " + ex.toString());
return;
}
try {
final ScoreCluster<String> domains = getDomains(stackType);
if (domains != null) {
domains.incScore(e.metadata().url().getHost());
}
} catch (final Exception ex) {
System.out.println("INTERNAL ERROR in newEntry/3: " + ex.toString());
return;
}
}
public synchronized int getStackSize(final int stack) {
final List<String> resultStack = getStack(stack);
if (resultStack == null) return 0;
return resultStack.size();
}
public synchronized int getDomainListSize(final int stack) {
final ScoreCluster<String> domains = getDomains(stack);
if (domains == null) return 0;
return domains.size();
}
public synchronized String getUrlHash(final int stack, final int pos) {
return getHashNo(stack, pos, 0);
}
public synchronized String getInitiatorHash(final int stack, final int pos) {
return getHashNo(stack, pos, 1);
}
public synchronized String getExecutorHash(final int stack, final int pos) {
return getHashNo(stack, pos, 2);
}
/**
* gets the hash at <em>index</em> in element at <em>pos</em> in <em>stack</em> (based on {@link yacySeedDB#commonHashLength})
*
* <p>simplified example with {@link yacySeedDB#commonHashLength} = 3:</p>
* <code>String[][] stacks[1][0] = "123456789";
* System.out.println(getHashNo(1, 0, 0));
* System.out.println(getHashNo(1, 0, 0));
* System.out.println(getHashNo(1, 0, 0));</code>
* <p>Output:
* 123<br/>
* 456<br/>
* 789</p>
*
* @param stack
* @param pos
* @param index starting at 0
* @return
*/
public synchronized String getHashNo(final int stack, final int pos, final int index) {
final String result = getResultStackAt(stack, pos);
if(result != null) {
if(result.length() < yacySeedDB.commonHashLength * 3) {
Log.logSevere("ResultURLs", "unexpected error: result of stack is too short: "+ result.length());
if(result.length() <= yacySeedDB.commonHashLength * 2) {
return null;
}
// return what is there
return result.substring(yacySeedDB.commonHashLength * 2);
}
return result.substring(yacySeedDB.commonHashLength * index, yacySeedDB.commonHashLength * (index + 1));
} else if(isValidStack(stack)) {
Log.logSevere("ResultURLs", "unexpected error: result of stack is null: "+ stack +","+ pos);
}
return result;
}
/**
* gets the element at pos in stack
*
* @param stack
* @param pos
* @return null if either stack or element do not exist
*/
private String getResultStackAt(final int stack, final int pos) {
assert pos >= 0 : "precondition violated: " + pos + " >= 0";
final List<String> resultStack = getStack(stack);
if(resultStack == null) {
return null;
}
assert pos < resultStack.size() : "pos = " + pos + ", resultStack.size() = " + resultStack.size();
if(pos >= resultStack.size()) {
Log.logSevere("ResultURLs", "unexpected error: Index out of Bounds "+ pos +" of "+ resultStack.size());
return null;
}
return resultStack.get(pos);
}
/**
* iterate all domains in the result domain statistic
* @return iterator of domains in reverse order (downwards)
*/
public Iterator<String> domains(final int stack) {
assert getDomains(stack) != null : "getDomains(" + stack + ") = null";
return getDomains(stack).scores(false);
}
public int deleteDomain(final int stack, String host, String hosthash) {
assert hosthash.length() == 6;
int i = 0;
while (i < getStackSize(stack)) {
if (getUrlHash(stack, i).substring(6).equals(hosthash)) getStack(stack).remove(i); else i++;
}
assert host != null : "host = null";
assert getDomains(stack) != null : "getDomains(" + stack + ") = null";
return getDomains(stack).deleteScore(host);
}
/**
* return the count of the domain
* @param stack type
* @param domain name
* @return the number of occurrences of the domain in the stack statistics
*/
public int domainCount(final int stack, String domain) {
assert domain != null : "domain = null";
assert getDomains(stack) != null : "getDomains(" + stack + ") = null";
return getDomains(stack).getScore(domain);
}
/**
* returns the stack indentified by the id <em>stack</em>
*
* @param stack id of resultStack
* @return null if stack does not exist (id is unknown or stack is null (which should not occur and an error is logged))
*/
private List<String> getStack(final int stack) {
switch (stack) {
case 1: return externResultStack;
case 2: return searchResultStack;
case 3: return transfResultStack;
case 4: return proxyResultStack;
case 5: return lcrawlResultStack;
case 6: return gcrawlResultStack;
default:
return null;
}
}
private ScoreCluster<String> getDomains(final int stack) {
switch (stack) {
case 1: return externResultDomains;
case 2: return searchResultDomains;
case 3: return transfResultDomains;
case 4: return proxyResultDomains;
case 5: return lcrawlResultDomains;
case 6: return gcrawlResultDomains;
default:
return null;
}
}
/**
* tests if a stack with id <em>stack</em> exists
*
* @param stack
* @return
*/
private boolean isValidStack(final int stack) {
return getStack(stack) != null;
}
public synchronized boolean removeStack(final int stack, final int pos) {
final List<String> resultStack = getStack(stack);
if (resultStack == null) {
return false;
}
return resultStack.remove(pos) != null;
}
public synchronized void clearStack(final int stack) {
final List<String> resultStack = getStack(stack);
if (resultStack != null) resultStack.clear();
final ScoreCluster<String> resultDomains = getDomains(stack);
if (resultDomains != null) {
// we do not clear this completely, just remove most of the less important entries
resultDomains.shrinkToMaxSize(100);
resultDomains.shrinkToMinScore(2);
}
}
public synchronized boolean remove(final String urlHash) {
if (urlHash == null) return false;
String hash;
for (int stack = 1; stack <= 6; stack++) {
for (int i = getStackSize(stack) - 1; i >= 0; i--) {
hash = getUrlHash(stack, i);
if (hash != null && hash.equals(urlHash)) {
removeStack(stack, i);
return true;
}
}
}
return true;
}
/**
* test and benchmark
* @param args
*/
public static void main(final String[] args) {
final ResultURLs results = new ResultURLs();
try {
final yacyURL url = new yacyURL("http", "www.yacy.net", 80, "/");
final URLMetadataRow urlRef = new URLMetadataRow(url, "YaCy Homepage", "", "", "", new Date(), new Date(), new Date(), "", new byte[] {}, 123, 42, '?', new Bitfield(), "de", 0, 0, 0, 0, 0, 0);
int stackNo = 1;
System.out.println("valid test:\n=======");
// add
results.stack(urlRef, urlRef.hash(), url.hash(), stackNo);
// size
System.out.println("size of stack:\t"+ results.getStackSize(stackNo));
// get
System.out.println("url hash:\t"+ results.getUrlHash(stackNo, 0));
System.out.println("executor hash:\t"+ results.getExecutorHash(stackNo, 0));
System.out.println("initiator hash:\t"+ results.getInitiatorHash(stackNo, 0));
// test errors
System.out.println("invalid test:\n=======");
// get
System.out.println("url hash:\t"+ results.getUrlHash(stackNo, 1));
System.out.println("executor hash:\t"+ results.getExecutorHash(stackNo, 1));
System.out.println("initiator hash:\t"+ results.getInitiatorHash(stackNo, 1));
stackNo = 42;
System.out.println("size of stack:\t"+ results.getStackSize(stackNo));
// get
System.out.println("url hash:\t"+ results.getUrlHash(stackNo, 0));
System.out.println("executor hash:\t"+ results.getExecutorHash(stackNo, 0));
System.out.println("initiator hash:\t"+ results.getInitiatorHash(stackNo, 0));
// benchmark
final long start = System.currentTimeMillis();
for(int i = 0; i < 1000000; i++) {
stackNo = i % 6;
// add
results.stack(urlRef, urlRef.hash(), url.hash(), stackNo);
// size
results.getStackSize(stackNo);
// get
for(int j = 0; j < 10; j++) {
results.getUrlHash(stackNo, i / 6);
results.getExecutorHash(stackNo, i / 6);
results.getInitiatorHash(stackNo, i / 6);
}
}
System.out.println("benschmark: "+ (System.currentTimeMillis() - start) + " ms");
} catch (final MalformedURLException e) {
e.printStackTrace();
}
}
}