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yacy_search_server/source/de/anomic/plasma/plasmaWordIndexEntity.java

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// plasmaWordIndexEntity.java
// --------------------------
// part of YACY
// (C) by Michael Peter Christen; mc@anomic.de
// first published on http://www.anomic.de
// Frankfurt, Germany, 2004
// last major change: 21.01.2004
//
// 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.Iterator;
import java.util.TreeMap;
import java.util.Set;
import de.anomic.kelondro.kelondroRecords;
import de.anomic.kelondro.kelondroTree;
import de.anomic.kelondro.kelondroException;
public final class plasmaWordIndexEntity {
private final String theWordHash;
private kelondroTree theIndex;
private TreeMap theTmpMap;
private File theLocation;
private boolean delete;
public plasmaWordIndexEntity(File databaseRoot, String wordHash, boolean deleteIfEmpty) throws IOException {
theWordHash = wordHash;
theIndex = indexFile(databaseRoot, wordHash);
theTmpMap = null;
delete = deleteIfEmpty;
}
public static boolean removePlasmaIndex(File databaseRoot, String wordHash) throws IOException {
File f = wordHash2path(databaseRoot, wordHash);
boolean success = true;
if (f.exists()) success = f.delete();
// clean up directory structure
f = f.getParentFile();
while ((f.isDirectory()) && (f.list().length == 0)) {
if (!(f.delete())) break;
f = f.getParentFile();
}
return success;
}
private kelondroTree indexFile(File databaseRoot, String wordHash) throws IOException {
if (wordHash.length() < 12) throw new IOException("word hash wrong: '" + wordHash + "'");
theLocation = wordHash2path(databaseRoot, wordHash);
File fp = theLocation.getParentFile();
if (fp != null) fp.mkdirs();
kelondroTree kt;
long cacheSize = theLocation.length();
if (cacheSize > 1048576) cacheSize = 1048576;
if (theLocation.exists()) {
// open existing index file
kt = new kelondroTree(theLocation, cacheSize);
} else {
// create new index file
kt = new kelondroTree(theLocation, cacheSize, plasmaURL.urlHashLength, plasmaWordIndexEntry.attrSpaceShort);
}
return kt; // everyone who get this should close it when finished!
}
public static File wordHash2path(File databaseRoot, String hash) {
// creates a path that constructs hashing on a file system
return new File (databaseRoot, "WORDS/" +
hash.substring(0,1) + "/" + hash.substring(1,2) + "/" + hash.substring(2,4) + "/" +
hash.substring(4,6) + "/" + hash + ".db");
}
public plasmaWordIndexEntity(String wordHash) {
// this creates a nameless temporary index. It is needed for combined search
// and used to hold the intersection of two indexes
// if the nameless intity is suppose to hold indexes for a specific word,
// it can be given here; othervise set wordhash to null
theWordHash = wordHash;
theIndex = null;
theLocation = null;
theTmpMap = new TreeMap();
}
public boolean isTMPEntity() {
return theTmpMap != null;
}
public String wordHash() {
return theWordHash;
}
public int size() {
if (theTmpMap == null) {
int size = theIndex.size();
if ((size == 0) && (delete)) {
try {
deleteComplete();
} catch (IOException e) {
delete = false;
}
return 0;
} else {
return size;
}
} else {
return theTmpMap.size();
}
}
public void close() throws IOException {
if (theTmpMap == null) {
if (theIndex != null) theIndex.close();
theIndex = null;
} else theTmpMap = null;
}
public void finalize() {
try {
close();
} catch (IOException e) {}
}
public boolean contains(String urlhash) throws IOException {
if (theTmpMap == null) return (theIndex.get(urlhash.getBytes()) != null); else return (theTmpMap.containsKey(urlhash));
}
public boolean contains(plasmaWordIndexEntry entry) throws IOException {
if (theTmpMap == null) return (theIndex.get(entry.getUrlHash().getBytes()) != null); else return (theTmpMap.containsKey(entry.getUrlHash()));
}
public boolean addEntry(plasmaWordIndexEntry entry) throws IOException {
if (theTmpMap == null) {
return (theIndex.put(entry.getUrlHash().getBytes(), entry.toEncodedForm(false).getBytes()) == null);
} else {
return (theTmpMap.put(entry.getUrlHash(), entry) == null);
}
}
public int addEntries(plasmaWordIndexEntryContainer container) throws IOException {
//System.out.println("* adding " + newEntries.size() + " cached word index entries for word " + wordHash); // debug
// fetch the index cache
if ((container == null) || (container.size() == 0)) return 0;
// open file
int count = 0;
// write from vector
if (container != null) {
Iterator i = container.entries();
while (i.hasNext()) {
if (addEntry((plasmaWordIndexEntry) i.next())) count++;
}
}
// close and return
return count;
}
public boolean deleteComplete() throws IOException {
if (theTmpMap == null) {
theIndex.close();
// remove file
boolean success = theLocation.delete();
// and also the paren directory if that is empty
if (success) {
File f = theLocation.getParentFile();
while ((f.isDirectory()) && (f.list().length == 0)) {
if (!(f.delete())) break;
f = f.getParentFile();
}
}
// reset all values
theIndex = null;
theLocation = null;
// switch to temporary more
theTmpMap = new TreeMap();
//theIndex.removeAll();
return success;
} else {
theTmpMap = new TreeMap();
return true;
}
}
public boolean removeEntry(String urlHash, boolean deleteComplete) throws IOException {
// returns true if there was an entry before, false if the key did not exist
// if after the removal the file is empty, then the file can be deleted if
// the flag deleteComplete is set.
if (theTmpMap == null) {
boolean wasEntry = (theIndex.remove(urlHash.getBytes()) != null);
if ((theIndex.size() == 0) && (deleteComplete)) deleteComplete();
return wasEntry;
} else {
return (theTmpMap.remove(urlHash) != null);
}
}
public Iterator elements(boolean up) {
// returns an enumeration of plasmaWordIndexEntry objects
if (theTmpMap == null) return new dbenum(up); else return new tmpenum(up);
}
public final class dbenum implements Iterator {
Iterator i;
public dbenum(boolean up) {
try {
i = theIndex.nodeIterator(up, false);
} catch (kelondroException e) {
e.printStackTrace();
theIndex.file().delete();
i = null;
}
}
public boolean hasNext() {
return (i != null) && (i.hasNext());
}
public Object next() {
if (i == null) return null;
try {
byte[][] n = ((kelondroRecords.Node) i.next()).getValues();
return new plasmaWordIndexEntry(new String(n[0]), new String(n[1]));
} catch (IOException e) {
i = null;
throw new RuntimeException("dbenum: " + e.getMessage());
} catch (kelondroException e) {
i = null;
throw new RuntimeException("dbenum: " + e.getMessage());
}
}
public void remove() {
throw new UnsupportedOperationException();
}
}
public final class tmpenum implements Iterator {
final TreeMap searchTree;
boolean up;
public tmpenum(boolean up) {
this.up = up;
searchTree = (TreeMap) theTmpMap.clone(); // a shallow clone that is destroyed during search
}
public boolean hasNext() {
return searchTree.size() > 0;
}
public Object next() {
Object urlHash = (up) ? searchTree.firstKey() : searchTree.lastKey();
plasmaWordIndexEntry entry = (plasmaWordIndexEntry) searchTree.remove(urlHash);
return entry;
}
public void remove() {
throw new UnsupportedOperationException();
}
}
public String toString() {
if (theTmpMap == null) return "DB:" + theIndex.toString();
else if (theTmpMap != null) return "MAP:" + theTmpMap.size() + " RECORDS IN " + theTmpMap.toString();
else return "EMPTY";
}
// join methods
private static int log2(int x) {
int l = 0;
while (x > 0) {x = x >> 1; l++;}
return l;
}
public void merge(plasmaWordIndexEntity otherEntity, long time) throws IOException {
// this is a merge of another entity to this entity
// the merge is interrupted when the given time is over
// a time=-1 means: no timeout
Iterator i = otherEntity.elements(true);
long timeout = (time == -1) ? Long.MAX_VALUE : System.currentTimeMillis() + time;
while ((i.hasNext()) && (System.currentTimeMillis() < timeout)) {
addEntry((plasmaWordIndexEntry) i.next());
}
}
public static plasmaWordIndexEntity joinEntities(Set entities, long time) throws IOException {
long stamp = System.currentTimeMillis();
// order entities by their size
TreeMap map = new TreeMap();
plasmaWordIndexEntity singleEntity;
Iterator i = entities.iterator();
int count = 0;
while (i.hasNext()) {
// get next entity:
singleEntity = (plasmaWordIndexEntity) i.next();
// check result
if ((singleEntity == null) || (singleEntity.size() == 0)) return new plasmaWordIndexEntity(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(new Long(singleEntity.size() * 1000 + count), singleEntity);
count++;
}
// check if there is any result
if (map.size() == 0) return new plasmaWordIndexEntity(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 = (Long) map.firstKey(); // the smallest, which means, the one with the least entries
plasmaWordIndexEntity searchA, searchB, searchResult = (plasmaWordIndexEntity) map.remove(k);
while ((map.size() > 0) && (searchResult.size() > 0) && (time > 0)) {
// take the first element of map which is a result and combine it with result
k = (Long) map.firstKey(); // the next smallest...
time -= (System.currentTimeMillis() - stamp); stamp = System.currentTimeMillis();
searchA = searchResult;
searchB = (plasmaWordIndexEntity) map.remove(k);
searchResult = plasmaWordIndexEntity.joinConstructive(searchA, searchB, 2 * time / (map.size() + 1));
// close the input files/structures
if (searchA != searchResult) searchA.close();
if (searchB != searchResult) searchB.close();
}
searchA = null; // free resources
searchB = null; // free resources
// in 'searchResult' is now the combined search result
if (searchResult.size() == 0) return new plasmaWordIndexEntity(null);
return searchResult;
}
public static plasmaWordIndexEntity joinConstructive(plasmaWordIndexEntity i1, plasmaWordIndexEntity i2, long time) throws IOException {
if ((i1 == null) || (i2 == null)) return null;
if ((i1.size() == 0) || (i2.size() == 0)) return new plasmaWordIndexEntity(null);
// decide which method to use
int high = ((i1.size() > i2.size()) ? i1.size() : i2.size());
int low = ((i1.size() > i2.size()) ? i2.size() : i1.size());
int stepsEnum = 10 * (high + low - 1);
int stepsTest = 12 * log2(high) * low;
// start most efficient method
if (stepsEnum > stepsTest) {
if (i1.size() < i2.size())
return joinConstructiveByTest(i1, i2, time);
else
return joinConstructiveByTest(i2, i1, time);
} else {
return joinConstructiveByEnumeration(i1, i2, time);
}
}
private static plasmaWordIndexEntity joinConstructiveByTest(plasmaWordIndexEntity small, plasmaWordIndexEntity large, long time) throws IOException {
System.out.println("DEBUG: JOIN METHOD BY TEST");
plasmaWordIndexEntity conj = new plasmaWordIndexEntity(null); // start with empty search result
Iterator se = small.elements(true);
plasmaWordIndexEntry ie;
long stamp = System.currentTimeMillis();
try {
while ((se.hasNext()) && ((System.currentTimeMillis() - stamp) < time)) {
ie = (plasmaWordIndexEntry) se.next();
if (large.contains(ie)) conj.addEntry(ie);
}
} catch (kelondroException e) {
//serverLog.logSevere("PLASMA", "joinConstructiveByTest: Database corrupt (" + e.getMessage() + "), deleting index");
small.deleteComplete();
return conj;
}
return conj;
}
private static plasmaWordIndexEntity joinConstructiveByEnumeration(plasmaWordIndexEntity i1, plasmaWordIndexEntity i2, long time) throws IOException {
System.out.println("DEBUG: JOIN METHOD BY ENUMERATION");
plasmaWordIndexEntity conj = new plasmaWordIndexEntity(null); // start with empty search result
Iterator e1 = i1.elements(true);
Iterator e2 = i2.elements(true);
int c;
if ((e1.hasNext()) && (e2.hasNext())) {
plasmaWordIndexEntry ie1;
plasmaWordIndexEntry ie2;
try {
ie1 = (plasmaWordIndexEntry) e1.next();
} catch (kelondroException e) {
//serverLog.logSevere("PLASMA", "joinConstructiveByEnumeration: Database corrupt 1 (" + e.getMessage() + "), deleting index");
i1.deleteComplete();
return conj;
}
try {
ie2 = (plasmaWordIndexEntry) e2.next();
} catch (kelondroException e) {
//serverLog.logSevere("PLASMA", "joinConstructiveByEnumeration: Database corrupt 2 (" + e.getMessage() + "), deleting index");
i2.deleteComplete();
return conj;
}
long stamp = System.currentTimeMillis();
while ((System.currentTimeMillis() - stamp) < time) {
c = ie1.getUrlHash().compareTo(ie2.getUrlHash());
if (c < 0) {
try {
if (e1.hasNext()) ie1 = (plasmaWordIndexEntry) e1.next(); else break;
} catch (kelondroException e) {
//serverLog.logSevere("PLASMA", "joinConstructiveByEnumeration: Database 1 corrupt (" + e.getMessage() + "), deleting index");
i1.deleteComplete();
break;
}
} else if (c > 0) {
try {
if (e2.hasNext()) ie2 = (plasmaWordIndexEntry) e2.next(); else break;
} catch (kelondroException e) {
//serverLog.logSevere("PLASMA", "joinConstructiveByEnumeration: Database 2 corrupt (" + e.getMessage() + "), deleting index");
i2.deleteComplete();
break;
}
} else {
// we have found the same urls in different searches!
conj.addEntry(ie1);
try {
if (e1.hasNext()) ie1 = (plasmaWordIndexEntry) e1.next(); else break;
} catch (kelondroException e) {
//serverLog.logSevere("PLASMA", "joinConstructiveByEnumeration: Database 1 corrupt (" + e.getMessage() + "), deleting index");
i1.deleteComplete();
break;
}
try {
if (e2.hasNext()) ie2 = (plasmaWordIndexEntry) e2.next(); else break;
} catch (kelondroException e) {
//serverLog.logSevere("PLASMA", "joinConstructiveByEnumeration: Database 2 corrupt (" + e.getMessage() + "), deleting index");
i2.deleteComplete();
break;
}
}
}
}
return conj;
}
}
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