// kRelations.java
// (C) 2008 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 3.07.2008 on http://yacy.net
//
// This is a part of YaCy, a peer-to-peer based web search engine
//
// $LastChangedDate: 2011-03-10 13:35:32 +0100 (Do, 10. Mär 2011) $
// $LastChangedRevision: 7580 $
// $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.table;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import net.yacy.cora.document.UTF8;
import net.yacy.kelondro.index.Index;
import net.yacy.kelondro.index.Row;
import net.yacy.kelondro.index.RowSpaceExceededException;
import net.yacy.kelondro.logging.Log;
import net.yacy.kelondro.order.NaturalOrder;
public class Relations {
private final File baseDir;
private HashMap<String, Index> relations;
private final boolean useTailCache;
private final boolean exceed134217727;
public Relations(
final File location,
final boolean useTailCache,
final boolean exceed134217727) {
this.baseDir = location;
this.useTailCache = useTailCache;
this.exceed134217727 = exceed134217727;
}
private static Row rowdef(String filename) {
int p = filename.lastIndexOf('.');
if (p >= 0) filename = filename.substring(0, p);
p = filename.lastIndexOf('-');
assert p >= 0;
final int payloadsize = Integer.parseInt(filename.substring(p + 1));
filename = filename.substring(0, p);
p = filename.lastIndexOf('-');
assert p >= 0;
final int keysize = Integer.parseInt(filename.substring(p + 1));
return rowdef(keysize, payloadsize);
}
private static Row rowdef(final int keysize, final int payloadsize) {
return new Row(
"byte[] key-" + keysize + ", " +
"long time-8" + keysize + ", " +
"int ttl-4" + keysize + ", " +
"byte[] node-" + payloadsize,
NaturalOrder.naturalOrder);
}
private static String filename(final String tablename, final int keysize, final int payloadsize) {
return tablename + "-" + keysize + "-" + payloadsize + ".eco";
}
public void declareRelation(final String name, final int keysize, final int payloadsize) throws RowSpaceExceededException {
// try to get the relation from the relation-cache
final Index relation = relations.get(name);
if (relation != null) return;
// try to find the relation as stored on file
final String[] list = baseDir.list();
final String targetfilename = filename(name, keysize, payloadsize);
for (int i = 0; i < list.length; i++) {
if (list[i].startsWith(name)) {
if (!list[i].equals(targetfilename)) continue;
final Row row = rowdef(list[i]);
if (row.primaryKeyLength != keysize || row.column(1).cellwidth != payloadsize) continue; // a wrong table
Index table;
try {
table = new Table(new File(baseDir, list[i]), row, 1024*1024, 0, this.useTailCache, this.exceed134217727);
} catch (RowSpaceExceededException e) {
table = new Table(new File(baseDir, list[i]), row, 0, 0, false, this.exceed134217727);
}
relations.put(name, table);
return;
}
}
// the relation does not exist, create it
final Row row = rowdef(keysize, payloadsize);
Index table;
try {
table = new Table(new File(baseDir, targetfilename), row, 1024*1024, 0, this.useTailCache, this.exceed134217727);
} catch (RowSpaceExceededException e) {
table = new Table(new File(baseDir, targetfilename), row, 0, 0, false, this.exceed134217727);
}
relations.put(name, table);
}
public Index getRelation(final String name) throws RowSpaceExceededException {
// try to get the relation from the relation-cache
final Index relation = relations.get(name);
if (relation != null) return relation;
// try to find the relation as stored on file
final String[] list = baseDir.list();
for (int i = 0; i < list.length; i++) {
if (list[i].startsWith(name)) {
final Row row = rowdef(list[i]);
Index table;
try {
table = new Table(new File(baseDir, list[i]), row, 1024*1024, 0, this.useTailCache, this.exceed134217727);
} catch (RowSpaceExceededException e) {
table = new Table(new File(baseDir, list[i]), row, 0, 0, false, this.exceed134217727);
}
relations.put(name, table);
return table;
}
}
// the relation does not exist
return null;
}
public String putRelation(final String name, final String key, final String value) throws IOException, RowSpaceExceededException {
final byte[] r = putRelation(name, UTF8.getBytes(key), UTF8.getBytes(value));
if (r == null) return null;
return UTF8.String(r);
}
public byte[] putRelation(final String name, final byte[] key, final byte[] value) throws IOException, RowSpaceExceededException {
final Index table = getRelation(name);
if (table == null) return null;
final Row.Entry entry = table.row().newEntry();
entry.setCol(0, key);
entry.setCol(1, System.currentTimeMillis());
entry.setCol(2, 1000000);
entry.setCol(3, value);
final Row.Entry oldentry = table.replace(entry);
if (oldentry == null) return null;
return oldentry.getColBytes(3, true);
}
public String getRelation(final String name, final String key) throws IOException, RowSpaceExceededException {
final byte[] r = getRelation(name, UTF8.getBytes(key));
if (r == null) return null;
return UTF8.String(r);
}
public byte[] getRelation(final String name, final byte[] key) throws IOException, RowSpaceExceededException {
final Index table = getRelation(name);
if (table == null) return null;
final Row.Entry entry = table.get(key);
if (entry == null) return null;
return entry.getColBytes(3, true);
}
public boolean hasRelation(final String name, final byte[] key) throws RowSpaceExceededException {
final Index table = getRelation(name);
if (table == null) return false;
return table.has(key);
}
public byte[] removeRelation(final String name, final byte[] key) throws IOException, RowSpaceExceededException {
final Index table = getRelation(name);
if (table == null) return null;
final Row.Entry entry = table.remove(key);
if (entry == null) return null;
return entry.getColBytes(3, true);
}
public static void main(final String args[]) {
final Relations r = new Relations(new File("/Users/admin/"), true, true);
try {
final String table1 = "test1";
r.declareRelation(table1, 12, 30);
r.putRelation(table1, "abcdefg", "eineintrag");
r.putRelation(table1, "abcdefg", "eineintrag");
} catch (final IOException e) {
Log.logException(e);
} catch (RowSpaceExceededException e) {
Log.logException(e);
}
}
}