// 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
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// 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.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.List;
import java.util.TreeMap;
import net.yacy.cora.document.ASCII;
import net.yacy.kelondro.index.HandleSet;
import net.yacy.kelondro.index.Row;
import net.yacy.kelondro.index.RowSet;
import net.yacy.kelondro.index.RowSpaceExceededException;
import net.yacy.kelondro.logging.Log;
import net.yacy.kelondro.order.Base64Order;
import net.yacy.kelondro.order.ByteOrder;
/**
* 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 static int maxReferences = 0; // overwrite this to enable automatic index shrinking. 0 means no shrinking
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) {
super(factory.getRow());
assert termHash == null || (termHash[2] != '@' && termHash.length == this.rowdef.primaryKeyLength);
this.termHash = termHash;
this.factory = factory;
this.lastTimeWrote = 0;
}
public ReferenceContainer(final ReferenceFactory<ReferenceType> factory, final byte[] termHash, final int objectCount) throws RowSpaceExceededException {
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() throws RowSpaceExceededException {
final ReferenceContainer<ReferenceType> newContainer = new ReferenceContainer<ReferenceType>(this.factory, this.termHash, size());
newContainer.addAllUnique(this);
return newContainer;
}
public static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> emptyContainer(final ReferenceFactory<ReferenceType> factory, final byte[] termHash) {
assert termHash == null || (termHash[2] != '@' && termHash.length == factory.getRow().primaryKeyLength);
return new ReferenceContainer<ReferenceType>(factory, termHash);
}
public static <ReferenceType extends Reference> ReferenceContainer<ReferenceType> emptyContainer(final ReferenceFactory<ReferenceType> factory, final byte[] termHash, final int elementCount) throws RowSpaceExceededException {
assert termHash == null || (termHash[2] != '@' && termHash.length == factory.getRow().primaryKeyLength);
return new ReferenceContainer<ReferenceType>(factory, termHash, elementCount);
}
public void setWordHash(final byte[] newTermHash) {
assert this.termHash == null || (this.termHash[2] != '@' && this.termHash.length == this.rowdef.primaryKeyLength);
this.termHash = newTermHash;
}
public long updated() {
return super.lastWrote();
}
public byte[] getTermHash() {
return this.termHash;
}
public void add(final Reference entry) throws RowSpaceExceededException {
// add without double-occurrence test
assert entry.toKelondroEntry().objectsize() == super.rowdef.objectsize;
this.addUnique(entry.toKelondroEntry());
}
public ReferenceContainer<ReferenceType> merge(final ReferenceContainer<ReferenceType> c) throws RowSpaceExceededException {
return new ReferenceContainer<ReferenceType>(this.factory, this.termHash, super.merge(c));
}
public Reference replace(final Reference entry) throws RowSpaceExceededException {
assert entry.toKelondroEntry().objectsize() == super.rowdef.objectsize;
final Row.Entry r = super.replace(entry.toKelondroEntry());
if (r == null) return null;
return this.factory.produceSlow(r);
}
public void put(final Reference entry) throws RowSpaceExceededException {
assert entry.toKelondroEntry().objectsize() == super.rowdef.objectsize;
super.put(entry.toKelondroEntry());
}
public boolean putRecent(final Reference entry) throws RowSpaceExceededException {
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 = this.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) throws RowSpaceExceededException {
// 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) {
Log.logException(e);
}
}
}
this.lastTimeWrote = java.lang.Math.max(this.lastTimeWrote, c.updated());
return x;
}
public ReferenceType getReference(final byte[] urlHash) {
final Row.Entry entry = super.get(urlHash, false);
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 removeReference(final byte[] urlHash) {
final Row.Entry entry = super.remove(urlHash);
if (entry == null) return null;
return this.factory.produceSlow(entry);
}
public int removeEntries(final HandleSet urlHashes) {
int count = 0;
final Iterator<byte[]> i = urlHashes.iterator();
while (i.hasNext()) count += (delete(i.next())) ? 1 : 0;
return count;
}
/**
* Shrink the reference size in such a way that it does not exceed maxReferences
* In case that the index is too large, old entries are deleted
* @return the number of deleted entries
*/
public int shrinkReferences() {
final int oldsize = size();
final int diff = oldsize - maxReferences;
if (maxReferences <= 0 || diff <= 0) return 0;
synchronized (this) {
final int[] indexes = oldPostions(diff);
Arrays.sort(indexes);
for (int i = indexes.length - 1; i >= 0; i--) {
if (indexes[i] < 0) break;
removeRow(indexes[i], false);
}
sort();
}
return oldsize - size();
}
private int[] oldPostions(final int count) {
final int[] indexes = new int[count];
int i = 0;
for (final List<Integer> positions : positionsByLastMod()) {
for (final Integer pos : positions) {
indexes[i++] = pos;
if (i >= count) return indexes;
}
}
return indexes;
}
private Collection<List<Integer>> positionsByLastMod() {
long mod;
List<Integer> positions;
ReferenceType r;
final TreeMap<Long, List<Integer>> tm = new TreeMap<Long, List<Integer>>();
final Iterator<ReferenceType> i = this.entries();
int pos = 0;
while (i.hasNext()) {
r = i.next();
if (r == null) continue;
mod = r.lastModified();
positions = tm.get(mod);
if (positions == null) positions = new ArrayList<Integer>();
positions.add(pos++);
tm.put(mod, positions);
}
return tm.values();
}
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() {
this.rowEntryIterator = iterator();
}
public boolean hasNext() {
return this.rowEntryIterator.hasNext();
}
public ReferenceType next() {
final Row.Entry rentry = this.rowEntryIterator.next();
if (rentry == null) return null;
return ReferenceContainer.this.factory.produceSlow(rentry);
}
public void remove() {
this.rowEntryIterator.remove();
}
}
public static Object mergeUnique(final Object a, final Object b) throws RowSpaceExceededException {
if (a instanceof ReferenceContainer<?>) {
final ReferenceContainer<?> c = (ReferenceContainer<?>) a;
c.addAllUnique((ReferenceContainer<?>) b);
return c;
}
throw new UnsupportedOperationException("Objects have wrong type: " + a.getClass().getName());
}
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) throws RowSpaceExceededException {
// 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) throws RowSpaceExceededException {
// 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.isEmpty()) 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.isEmpty()) 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.isEmpty() && !searchResult.isEmpty()) {
// 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.isEmpty()) 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.isEmpty()) 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.isEmpty()) 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) throws RowSpaceExceededException {
if ((i1 == null) || (i2 == null)) return null;
if (i1.isEmpty() || i2.isEmpty()) 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) throws RowSpaceExceededException {
//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.getReference(ie1.urlhash());
if ((ie1 != null) && (ie2 != null)) {
assert (ie1.urlhash().length == keylength) : "ie0.urlHash() = " + ASCII.String(ie1.urlhash());
assert (ie2.urlhash().length == keylength) : "ie1.urlHash() = " + ASCII.String(ie2.urlhash());
// 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) throws RowSpaceExceededException {
//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
final 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.urlhash().length == keylength) : "ie1.urlHash() = " + ASCII.String(ie1.urlhash());
assert (ie2.urlhash().length == keylength) : "ie2.urlHash() = " + ASCII.String(ie2.urlhash());
c = ordering.compare(ie1.urlhash(), ie2.urlhash());
//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.isEmpty()) return null;
if (excl.isEmpty()) 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.getReference(ie0.urlhash());
if ((ie0 != null) && (ie1 != null)) {
assert (ie0.urlhash().length == keylength) : "ie0.urlHash() = " + ASCII.String(ie0.urlhash());
assert (ie1.urlhash().length == keylength) : "ie1.urlHash() = " + ASCII.String(ie1.urlhash());
if (iterate_pivot) se.remove(); pivot.delete(ie0.urlhash());
}
}
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.urlhash().length == keylength) : "ie1.urlHash() = " + ASCII.String(ie1.urlhash());
assert (ie2.urlhash().length == keylength) : "ie2.urlHash() = " + ASCII.String(ie2.urlhash());
c = pivot.rowdef.getOrdering().compare(ie1.urlhash(), ie2.urlhash());
//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[" + ASCII.String(this.termHash) + "] has " + size() + " entries";
}
public int hashCode() {
return (int) Base64Order.enhancedCoder.decodeLong(this.termHash, 0, 4);
}
}