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package de.lmu.ifi.dbs.elki.index.tree.spatial.rstarvariants.rdknn;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2015
Ludwig-Maximilians-Universität München
Lehr- und Forschungseinheit für Datenbanksysteme
ELKI Development Team
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 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 Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
import java.io.IOException;
import java.io.RandomAccessFile;
import de.lmu.ifi.dbs.elki.index.tree.TreeIndexHeader;
/**
* Encapsulates the header information of a RDkNN-Tree. This information is
* needed for persistent storage.
*
* @author Elke Achtert
* @since 0.2
*/
class RdKNNTreeHeader extends TreeIndexHeader {
/**
* The size of this header in Bytes, which is 4 Bytes (for {@link #k_max}).
*/
private static int SIZE = 4;
/**
* The maximum number k of reverse kNN queries to be supported.
*/
int k_max;
/**
* Empty constructor for serialization.
*/
public RdKNNTreeHeader() {
super();
}
/**
* Creates a new header with the specified parameters.
*
* @param pageSize the size of a page in bytes
* @param dirCapacity the maximum number of entries in a directory node
* @param leafCapacity the maximum number of entries in a leaf node
* @param dirMinimum the minimum number of entries in a directory node
* @param leafMinimum the minimum number of entries in a leaf node
* @param k_max the maximum number k of reverse kNN queries to be supported
*/
public RdKNNTreeHeader(int pageSize, int dirCapacity, int leafCapacity, int dirMinimum, int leafMinimum, int k_max) {
super(pageSize, dirCapacity, leafCapacity, dirMinimum, leafMinimum);
this.k_max = k_max;
}
/**
* Initializes this header from the specified file. Calls
* {@link de.lmu.ifi.dbs.elki.index.tree.TreeIndexHeader#readHeader(java.io.RandomAccessFile)
* TreeIndexHeader#readHeader(file)} and reads additionally the integer value
* of {@link #k_max} from the file.
*/
@Override
public void readHeader(RandomAccessFile file) throws IOException {
super.readHeader(file);
this.k_max = file.readInt();
}
/**
* Writes this header to the specified file. Calls
* {@link de.lmu.ifi.dbs.elki.index.tree.TreeIndexHeader#writeHeader(java.io.RandomAccessFile)}
* and writes additionally the integer value of {@link #k_max} to the file.
*/
@Override
public void writeHeader(RandomAccessFile file) throws IOException {
super.writeHeader(file);
file.writeInt(this.k_max);
}
/**
* Returns {@link de.lmu.ifi.dbs.elki.index.tree.TreeIndexHeader#size()} plus
* the value of {@link #SIZE}).
*/
@Override
public int size() {
return super.size() + SIZE;
}
}
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