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yacy_search_server/source/net/yacy/kelondro/rwi/ReferenceContainer.java

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// ReferenceContainer.java
// (C) 2006 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 04.07.2006 on http://yacy.net
//
// This is a part of YaCy, a peer-to-peer based web search engine
//
// $LastChangedDate: 2009-10-10 01:32:08 +0200 (Sa, 10 Okt 2009) $
// $LastChangedRevision: 6393 $
// $LastChangedBy: orbiter $
//
// LICENSE
//
// 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
package net.yacy.kelondro.rwi;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import net.yacy.kelondro.index.Row;
import net.yacy.kelondro.index.RowSet;
import net.yacy.kelondro.order.Base64Order;
import net.yacy.kelondro.order.ByteOrder;
import net.yacy.kelondro.util.ByteBuffer;
/**
* A ReferenceContainer is a set of ReferenceRows entries for a specific term.
* Since ReferenceRow entries are special Row entries, a collection of ReferenceRows
* can be contained in a RowSet.
* This class extends the RowSet with methods for the handling of
* special ReferenceRow Row entry objects.
*/
public class ReferenceContainer<ReferenceType extends Reference> extends RowSet {
private byte[] termHash;
protected ReferenceFactory<ReferenceType> factory;
public ReferenceContainer(final ReferenceFactory<ReferenceType> factory, final byte[] termHash, final RowSet collection) {
super(collection);
assert termHash == null || (termHash[2] != '@' && termHash.length == this.rowdef.primaryKeyLength);
this.factory = factory;
this.termHash = termHash;
}
public ReferenceContainer(final ReferenceFactory<ReferenceType> factory, final byte[] termHash, final int objectCount) {
super(factory.getRow(), objectCount);
assert termHash == null || (termHash[2] != '@' && termHash.length == this.rowdef.primaryKeyLength);
this.termHash = termHash;
this.factory = factory;
this.lastTimeWrote = 0;
}
public ReferenceContainer<ReferenceType> topLevelClone() {
final ReferenceContainer<ReferenceType> newContainer = new ReferenceContainer<ReferenceType>(this.factory, this.termHash, this.size());
newContainer.addAllUnique(this);
return newContainer;
}
public static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> emptyContainer(final ReferenceFactory<ReferenceType> factory, final byte[] termHash, final int elementCount) {
assert termHash == null || (termHash[2] != '@' && termHash.length == factory.getRow().primaryKeyLength);
return new ReferenceContainer<ReferenceType>(factory, termHash, elementCount);
}
public void setWordHash(final byte[] newTermHash) {
assert termHash == null || (termHash[2] != '@' && termHash.length == this.rowdef.primaryKeyLength);
this.termHash = newTermHash;
}
public long updated() {
return super.lastWrote();
}
public byte[] getTermHash() {
return termHash;
}
public String getTermHashAsString() {
return new String(termHash);
}
public void add(final Reference entry) {
// add without double-occurrence test
assert entry.toKelondroEntry().objectsize() == super.rowdef.objectsize;
this.addUnique(entry.toKelondroEntry());
}
public ReferenceContainer<ReferenceType> merge(final ReferenceContainer<ReferenceType> c) {
return new ReferenceContainer<ReferenceType>(this.factory, this.termHash, super.merge(c));
}
public Reference replace(final Reference entry) {
assert entry.toKelondroEntry().objectsize() == super.rowdef.objectsize;
final Row.Entry r = super.replace(entry.toKelondroEntry());
if (r == null) return null;
return factory.produceSlow(r);
}
public void put(final Reference entry) {
assert entry.toKelondroEntry().objectsize() == super.rowdef.objectsize;
super.put(entry.toKelondroEntry());
}
public boolean putRecent(final Reference entry) {
assert entry.toKelondroEntry().objectsize() == super.rowdef.objectsize;
// returns true if the new entry was added, false if it already existed
final Row.Entry oldEntryRow = this.replace(entry.toKelondroEntry());
if (oldEntryRow == null) {
return true;
}
final Reference oldEntry = factory.produceSlow(oldEntryRow);
if (entry.isOlder(oldEntry)) { // A more recent Entry is already in this container
this.replace(oldEntry.toKelondroEntry()); // put it back
return false;
}
return true;
}
public int putAllRecent(final ReferenceContainer<ReferenceType> c) {
// adds all entries in c and checks every entry for double-occurrence
// returns the number of new elements
if (c == null) return 0;
int x = 0;
synchronized (c) {
final Iterator<ReferenceType> i = c.entries();
while (i.hasNext()) {
try {
if (putRecent(i.next())) x++;
} catch (final ConcurrentModificationException e) {
e.printStackTrace();
}
}
}
this.lastTimeWrote = java.lang.Math.max(this.lastTimeWrote, c.updated());
return x;
}
public ReferenceType get(final String urlHash) {
final Row.Entry entry = this.get(urlHash.getBytes());
if (entry == null) return null;
return this.factory.produceSlow(entry);
}
/**
* remove a url reference from the container.
* if the url hash was found, return the entry, but delete the entry from the container
* if the entry was not found, return null.
*/
public ReferenceType remove(final String urlHash) {
final Row.Entry entry = remove(urlHash.getBytes());
if (entry == null) return null;
return this.factory.produceSlow(entry);
}
public int removeEntries(final Set<String> urlHashes) {
int count = 0;
final Iterator<String> i = urlHashes.iterator();
while (i.hasNext()) count += (remove(i.next()) == null) ? 0 : 1;
return count;
}
public Iterator<ReferenceType> entries() {
// returns an iterator of indexRWIEntry objects
return new entryIterator();
}
public class entryIterator implements Iterator<ReferenceType> {
Iterator<Row.Entry> rowEntryIterator;
public entryIterator() {
rowEntryIterator = iterator();
}
public boolean hasNext() {
return rowEntryIterator.hasNext();
}
public ReferenceType next() {
final Row.Entry rentry = rowEntryIterator.next();
if (rentry == null) return null;
return factory.produceSlow(rentry);
}
public void remove() {
rowEntryIterator.remove();
}
}
public static Object mergeUnique(final Object a, final Object b) {
final ReferenceContainer<?> c = (ReferenceContainer<?>) a;
c.addAllUnique((ReferenceContainer<?>) b);
return c;
}
public static final Method containerMergeMethod;
static {
Method meth = null;
try {
final Class<?> c = net.yacy.kelondro.rwi.ReferenceContainer.class;
meth = c.getMethod("mergeUnique", new Class[]{Object.class, Object.class});
} catch (final SecurityException e) {
System.out.println("Error while initializing containerMerge.SecurityException: " + e.getMessage());
meth = null;
} catch (final NoSuchMethodException e) {
System.out.println("Error while initializing containerMerge.NoSuchMethodException: " + e.getMessage());
meth = null;
}
assert meth != null;
containerMergeMethod = meth;
}
public static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> joinExcludeContainers(
final ReferenceFactory<ReferenceType> factory,
final Collection<ReferenceContainer<ReferenceType>> includeContainers,
final Collection<ReferenceContainer<ReferenceType>> excludeContainers,
final int maxDistance) {
// join a search result and return the joincount (number of pages after join)
// since this is a conjunction we return an empty entity if any word is not known
if (includeContainers == null) return ReferenceContainer.emptyContainer(factory, null, 0);
// join the result
final ReferenceContainer<ReferenceType> rcLocal = ReferenceContainer.joinContainers(factory, includeContainers, maxDistance);
if (rcLocal == null) return ReferenceContainer.emptyContainer(factory, null, 0);
excludeContainers(factory, rcLocal, excludeContainers);
return rcLocal;
}
public static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> joinContainers(
final ReferenceFactory<ReferenceType> factory,
final Collection<ReferenceContainer<ReferenceType>> containers,
final int maxDistance) {
// order entities by their size
final TreeMap<Long, ReferenceContainer<ReferenceType>> map = new TreeMap<Long, ReferenceContainer<ReferenceType>>();
ReferenceContainer<ReferenceType> singleContainer;
final Iterator<ReferenceContainer<ReferenceType>> i = containers.iterator();
int count = 0;
while (i.hasNext()) {
// get next entity:
singleContainer = i.next();
// check result
if ((singleContainer == null) || (singleContainer.size() == 0)) return null; // as this is a cunjunction of searches, we have no result if any word is not known
// store result in order of result size
map.put(Long.valueOf(singleContainer.size() * 1000 + count), singleContainer);
count++;
}
// check if there is any result
if (map.size() == 0) return null; // no result, nothing found
// the map now holds the search results in order of number of hits per word
// we now must pairwise build up a conjunction of these sets
Long k = map.firstKey(); // the smallest, which means, the one with the least entries
ReferenceContainer<ReferenceType> searchA, searchB, searchResult = map.remove(k);
while ((map.size() > 0) && (searchResult.size() > 0)) {
// take the first element of map which is a result and combine it with result
k = map.firstKey(); // the next smallest...
searchA = searchResult;
searchB = map.remove(k);
searchResult = ReferenceContainer.joinConstructive(factory, searchA, searchB, maxDistance);
// free resources
searchA = null;
searchB = null;
}
// in 'searchResult' is now the combined search result
if (searchResult.size() == 0) return null;
return searchResult;
}
public static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> excludeContainers(
final ReferenceFactory<ReferenceType> factory,
ReferenceContainer<ReferenceType> pivot,
final Collection<ReferenceContainer<ReferenceType>> containers) {
// check if there is any result
if ((containers == null) || (containers.size() == 0)) return pivot; // no result, nothing found
final Iterator<ReferenceContainer<ReferenceType>> i = containers.iterator();
while (i.hasNext()) {
pivot = excludeDestructive(factory, pivot, i.next());
if ((pivot == null) || (pivot.size() == 0)) return null;
}
return pivot;
}
// join methods
private static int log2(int x) {
int l = 0;
while (x > 0) {x = x >> 1; l++;}
return l;
}
public static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> joinConstructive(
final ReferenceFactory<ReferenceType> factory,
final ReferenceContainer<ReferenceType> i1,
final ReferenceContainer<ReferenceType> i2,
final int maxDistance) {
if ((i1 == null) || (i2 == null)) return null;
if ((i1.size() == 0) || (i2.size() == 0)) return null;
// decide which method to use
final int high = ((i1.size() > i2.size()) ? i1.size() : i2.size());
final int low = ((i1.size() > i2.size()) ? i2.size() : i1.size());
final int stepsEnum = 10 * (high + low - 1);
final int stepsTest = 12 * log2(high) * low;
// start most efficient method
if (stepsEnum > stepsTest) {
if (i1.size() < i2.size())
return joinConstructiveByTest(factory, i1, i2, maxDistance);
else
return joinConstructiveByTest(factory, i2, i1, maxDistance);
}
return joinConstructiveByEnumeration(factory, i1, i2, maxDistance);
}
private static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> joinConstructiveByTest(
final ReferenceFactory<ReferenceType> factory,
final ReferenceContainer<ReferenceType> small,
final ReferenceContainer<ReferenceType> large,
final int maxDistance) {
//System.out.println("DEBUG: JOIN METHOD BY TEST, maxdistance = " + maxDistance);
assert small.rowdef.equals(large.rowdef) : "small = " + small.rowdef.toString() + "; large = " + large.rowdef.toString();
final int keylength = small.rowdef.width(0);
assert (keylength == large.rowdef.width(0));
final ReferenceContainer<ReferenceType> conj = new ReferenceContainer<ReferenceType>(factory, null, 0); // start with empty search result
final Iterator<ReferenceType> se = small.entries();
ReferenceType ie1;
ReferenceType ie2;
while (se.hasNext()) {
ie1 = se.next();
ie2 = large.get(ie1.metadataHash());
if ((ie1 != null) && (ie2 != null)) {
assert (ie1.metadataHash().length() == keylength) : "ie0.urlHash() = " + ie1.metadataHash();
assert (ie2.metadataHash().length() == keylength) : "ie1.urlHash() = " + ie2.metadataHash();
// this is a hit. Calculate word distance:
ie1 = factory.produceFast(ie2);
ie1.join(ie2);
if (ie1.distance() <= maxDistance) conj.add(ie1);
}
}
return conj;
}
private static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> joinConstructiveByEnumeration(
final ReferenceFactory<ReferenceType> factory,
final ReferenceContainer<ReferenceType> i1,
final ReferenceContainer<ReferenceType> i2,
final int maxDistance) {
//System.out.println("DEBUG: JOIN METHOD BY ENUMERATION, maxdistance = " + maxDistance);
assert i1.rowdef.equals(i2.rowdef) : "i1 = " + i1.rowdef.toString() + "; i2 = " + i2.rowdef.toString();
final int keylength = i1.rowdef.width(0);
assert (keylength == i2.rowdef.width(0));
final ReferenceContainer<ReferenceType> conj = new ReferenceContainer<ReferenceType>(factory, null, 0); // start with empty search result
if (!((i1.rowdef.getOrdering().signature().equals(i2.rowdef.getOrdering().signature())))) return conj; // ordering must be equal
ByteOrder ordering = i1.rowdef.getOrdering();
final Iterator<ReferenceType> e1 = i1.entries();
final Iterator<ReferenceType> e2 = i2.entries();
int c;
if ((e1.hasNext()) && (e2.hasNext())) {
ReferenceType ie1;
ReferenceType ie2;
ie1 = e1.next();
ie2 = e2.next();
while (true) {
assert (ie1.metadataHash().length() == keylength) : "ie1.urlHash() = " + ie1.metadataHash();
assert (ie2.metadataHash().length() == keylength) : "ie2.urlHash() = " + ie2.metadataHash();
c = ordering.compare(ie1.metadataHash().getBytes(), ie2.metadataHash().getBytes());
//System.out.println("** '" + ie1.getUrlHash() + "'.compareTo('" + ie2.getUrlHash() + "')="+c);
if (c < 0) {
if (e1.hasNext()) ie1 = e1.next(); else break;
} else if (c > 0) {
if (e2.hasNext()) ie2 = e2.next(); else break;
} else {
// we have found the same urls in different searches!
ie1 = factory.produceFast(ie1);
ie1.join(ie2);
if (ie1.distance() <= maxDistance) conj.add(ie1);
if (e1.hasNext()) ie1 = e1.next(); else break;
if (e2.hasNext()) ie2 = e2.next(); else break;
}
}
}
return conj;
}
public static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> excludeDestructive(
final ReferenceFactory<ReferenceType> factory,
final ReferenceContainer<ReferenceType> pivot,
final ReferenceContainer<ReferenceType> excl) {
if (pivot == null) return null;
if (excl == null) return pivot;
if (pivot.size() == 0) return null;
if (excl.size() == 0) return pivot;
// decide which method to use
final int high = ((pivot.size() > excl.size()) ? pivot.size() : excl.size());
final int low = ((pivot.size() > excl.size()) ? excl.size() : pivot.size());
final int stepsEnum = 10 * (high + low - 1);
final int stepsTest = 12 * log2(high) * low;
// start most efficient method
if (stepsEnum > stepsTest) {
return excludeDestructiveByTest(pivot, excl);
}
return excludeDestructiveByEnumeration(factory, pivot, excl);
}
private static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> excludeDestructiveByTest(
final ReferenceContainer<ReferenceType> pivot,
final ReferenceContainer<ReferenceType> excl) {
assert pivot.rowdef.equals(excl.rowdef) : "small = " + pivot.rowdef.toString() + "; large = " + excl.rowdef.toString();
final int keylength = pivot.rowdef.width(0);
assert (keylength == excl.rowdef.width(0));
final boolean iterate_pivot = pivot.size() < excl.size();
final Iterator<ReferenceType> se = (iterate_pivot) ? pivot.entries() : excl.entries();
Reference ie0, ie1;
while (se.hasNext()) {
ie0 = se.next();
ie1 = excl.get(ie0.metadataHash());
if ((ie0 != null) && (ie1 != null)) {
assert (ie0.metadataHash().length() == keylength) : "ie0.urlHash() = " + ie0.metadataHash();
assert (ie1.metadataHash().length() == keylength) : "ie1.urlHash() = " + ie1.metadataHash();
if (iterate_pivot) se.remove(); pivot.remove(ie0.metadataHash().getBytes());
}
}
return pivot;
}
private static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> excludeDestructiveByEnumeration(
final ReferenceFactory<ReferenceType> factory,
final ReferenceContainer<ReferenceType> pivot,
final ReferenceContainer<ReferenceType> excl) {
assert pivot.rowdef.equals(excl.rowdef) : "i1 = " + pivot.rowdef.toString() + "; i2 = " + excl.rowdef.toString();
final int keylength = pivot.rowdef.width(0);
assert (keylength == excl.rowdef.width(0));
if (!((pivot.rowdef.getOrdering().signature().equals(excl.rowdef.getOrdering().signature())))) return pivot; // ordering must be equal
final Iterator<ReferenceType> e1 = pivot.entries();
final Iterator<ReferenceType> e2 = excl.entries();
int c;
if ((e1.hasNext()) && (e2.hasNext())) {
ReferenceType ie1;
ReferenceType ie2;
ie1 = e1.next();
ie2 = e2.next();
while (true) {
assert (ie1.metadataHash().length() == keylength) : "ie1.urlHash() = " + ie1.metadataHash();
assert (ie2.metadataHash().length() == keylength) : "ie2.urlHash() = " + ie2.metadataHash();
c = pivot.rowdef.getOrdering().compare(ie1.metadataHash().getBytes(), ie2.metadataHash().getBytes());
//System.out.println("** '" + ie1.getUrlHash() + "'.compareTo('" + ie2.getUrlHash() + "')="+c);
if (c < 0) {
if (e1.hasNext()) ie1 = e1.next(); else break;
} else if (c > 0) {
if (e2.hasNext()) ie2 = e2.next(); else break;
} else {
// we have found the same urls in different searches!
ie1 = factory.produceFast(ie1);
ie1.join(ie2);
e1.remove();
if (e1.hasNext()) ie1 = e1.next(); else break;
if (e2.hasNext()) ie2 = e2.next(); else break;
}
}
}
return pivot;
}
public synchronized String toString() {
return "C[" + new String(termHash) + "] has " + this.size() + " entries";
}
public int hashCode() {
return (int) Base64Order.enhancedCoder.decodeLong(new String(this.termHash).substring(0, 4));
}
public static final <ReferenceType extends Reference> ByteBuffer compressIndex(final ReferenceContainer<ReferenceType> inputContainer, final ReferenceContainer<ReferenceType> excludeContainer, final long maxtime) {
// collect references according to domains
final long timeout = (maxtime < 0) ? Long.MAX_VALUE : System.currentTimeMillis() + maxtime;
final TreeMap<String, String> doms = new TreeMap<String, String>();
synchronized (inputContainer) {
final Iterator<ReferenceType> i = inputContainer.entries();
Reference iEntry;
String dom, paths;
while (i.hasNext()) {
iEntry = i.next();
if ((excludeContainer != null) && (excludeContainer.get(iEntry.metadataHash()) != null)) continue; // do not include urls that are in excludeContainer
dom = iEntry.metadataHash().substring(6);
if ((paths = doms.get(dom)) == null) {
doms.put(dom, iEntry.metadataHash().substring(0, 6));
} else {
doms.put(dom, paths + iEntry.metadataHash().substring(0, 6));
}
if (System.currentTimeMillis() > timeout)
break;
}
}
// construct a result string
final ByteBuffer bb = new ByteBuffer(inputContainer.size() * 6);
bb.append('{');
final Iterator<Map.Entry<String, String>> i = doms.entrySet().iterator();
Map.Entry<String, String> entry;
while (i.hasNext()) {
entry = i.next();
bb.append(entry.getKey());
bb.append(':');
bb.append(entry.getValue());
if (System.currentTimeMillis() > timeout)
break;
if (i.hasNext())
bb.append(',');
}
bb.append('}');
return bb;
}
public static final <ReferenceType extends Reference> void decompressIndex(final TreeMap<String, String> target, ByteBuffer ci, final String peerhash) {
// target is a mapping from url-hashes to a string of peer-hashes
if ((ci.byteAt(0) == '{') && (ci.byteAt(ci.length() - 1) == '}')) {
//System.out.println("DEBUG-DECOMPRESS: input is " + ci.toString());
ci = ci.trim(1, ci.length() - 2);
String dom, url, peers;
while ((ci.length() >= 13) && (ci.byteAt(6) == ':')) {
assert ci.length() >= 6 : "ci.length() = " + ci.length();
dom = ci.toString(0, 6);
ci.trim(7);
while ((ci.length() > 0) && (ci.byteAt(0) != ',')) {
assert ci.length() >= 6 : "ci.length() = " + ci.length();
url = ci.toString(0, 6) + dom;
ci.trim(6);
peers = target.get(url);
if (peers == null) {
target.put(url, peerhash);
} else {
target.put(url, peers + peerhash);
}
//System.out.println("DEBUG-DECOMPRESS: " + url + ":" + target.get(url));
}
if (ci.byteAt(0) == ',') ci.trim(1);
}
}
}
}