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

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8.1 KiB

// plasmaWordIndexFile.java
// --------------------------
// part of YACY
// (C) by Michael Peter Christen; mc@anomic.de
// first published on http://www.anomic.de
// Frankfurt, Germany, 2004
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// 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 de.anomic.index.indexContainer;
import de.anomic.index.indexRWIEntry;
import de.anomic.index.indexRWIEntryNew;
import de.anomic.index.indexRWIEntryOld;
import de.anomic.kelondro.kelondroBase64Order;
import de.anomic.kelondro.kelondroException;
import de.anomic.kelondro.kelondroRow;
import de.anomic.kelondro.kelondroTree;
import de.anomic.yacy.yacySeedDB;
public final class plasmaWordIndexFile {
private final String theWordHash;
private kelondroTree theIndex;
private File theLocation;
public plasmaWordIndexFile(File databaseRoot, String wordHash) {
theWordHash = wordHash;
theIndex = indexFile(databaseRoot, wordHash);
}
public static boolean removePlasmaIndex(File databaseRoot, String wordHash) {
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) {
if (wordHash.length() < 12) throw new RuntimeException("word hash wrong: '" + wordHash + "'");
theLocation = wordHash2path(databaseRoot, wordHash);
File fp = theLocation.getParentFile();
if (fp != null) fp.mkdirs();
return kelondroTree.open(theLocation, true, 0,
new kelondroRow("byte[] urlhash-" + yacySeedDB.commonHashLength + ", byte[] ba-" + (indexRWIEntryOld.urlEntryRow.objectsize() - yacySeedDB.commonHashLength),
kelondroBase64Order.enhancedCoder, 0));
}
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 String wordHash() {
return theWordHash;
}
public int size() {
if (theIndex == null) return 0;
int size = theIndex.size();
if (size == 0) {
deleteComplete();
return 0;
} else {
return size;
}
}
public void close() throws IOException {
if (theIndex != null) theIndex.close();
theIndex = null;
}
public void finalize() {
try {
close();
} catch (IOException e) {}
}
public indexRWIEntry getEntry(String urlhash) throws IOException {
kelondroRow.Entry n = theIndex.get(urlhash.getBytes());
if (n == null) return null;
try {
return new indexRWIEntryNew(new indexRWIEntryOld(n.getColString(0, null), n.getColString(1, null)));
} catch (kelondroException e) {return null;}
}
public boolean contains(String urlhash) throws IOException {
return (theIndex.get(urlhash.getBytes()) != null);
}
public boolean contains(indexRWIEntry entry) throws IOException {
return (theIndex.get(entry.urlHash().getBytes()) != null);
}
public void addEntries(indexContainer container) {
throw new UnsupportedOperationException("word files are not supported in YaCy 0.491 and above");
}
public boolean deleteComplete() {
if (theIndex == null) return false;
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;
return success;
}
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 (urlHash == null || theIndex == null) return false;
boolean wasEntry = (theIndex.remove(urlHash.getBytes()) != null);
if ((theIndex.size() == 0) && (deleteComplete)) deleteComplete();
return wasEntry;
}
public Iterator elements(boolean up) {
// returns an enumeration of plasmaWordIndexEntry objects
return new dbenum(up);
}
public final class dbenum implements Iterator {
Iterator i;
public dbenum(boolean up) {
if (theIndex == null) {
i = null;
} else try {
i = theIndex.contentRows(-1);
} catch (kelondroException e) {
e.printStackTrace();
new File(theIndex.filename()).delete();
i = null;
}
}
public boolean hasNext() {
return (i != null) && (i.hasNext());
}
public Object next() {
if (i == null) return null;
kelondroRow.Entry n = (kelondroRow.Entry) i.next();
try {
return new indexRWIEntryNew(new indexRWIEntryOld(n.getColString(0, null), n.getColString(1, null)));
} catch (kelondroException e) { return null; }
}
public void remove() {
throw new UnsupportedOperationException();
}
}
public String toString() {
return "DB:" + theIndex.toString();
}
}