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package de.lmu.ifi.dbs.elki.index.tree.spatial.rstarvariants.flat;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2014
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.util.List;
import de.lmu.ifi.dbs.elki.data.ModifiableHyperBoundingBox;
import de.lmu.ifi.dbs.elki.index.tree.TreeIndexHeader;
import de.lmu.ifi.dbs.elki.index.tree.spatial.SpatialDirectoryEntry;
import de.lmu.ifi.dbs.elki.index.tree.spatial.SpatialEntry;
import de.lmu.ifi.dbs.elki.index.tree.spatial.rstarvariants.AbstractRStarTree;
import de.lmu.ifi.dbs.elki.index.tree.spatial.rstarvariants.AbstractRTreeSettings;
import de.lmu.ifi.dbs.elki.logging.Logging;
import de.lmu.ifi.dbs.elki.persistent.PageFile;
/**
* FlatRTree is a spatial index structure based on a R*-Tree but with a flat
* directory. Apart from organizing the objects it also provides several methods
* to search for certain object in the structure and ensures persistence.
*
* @author Elke Achtert
*
* @apiviz.has FlatRStarTreeNode oneway - - contains
*/
public class FlatRStarTree extends AbstractRStarTree<FlatRStarTreeNode, SpatialEntry, AbstractRTreeSettings> {
/**
* The logger for this class.
*/
private static final Logging LOG = Logging.getLogger(FlatRStarTree.class);
/**
* The root of this flat RTree.
*/
private FlatRStarTreeNode root;
/**
* Constructor.
*
* @param pagefile Page file
* @param settings Tree settings
*/
public FlatRStarTree(PageFile<FlatRStarTreeNode> pagefile, AbstractRTreeSettings settings) {
super(pagefile, settings);
}
/**
* Initializes the flat RTree from an existing persistent file.
*/
@Override
public void initializeFromFile(TreeIndexHeader header, PageFile<FlatRStarTreeNode> file) {
super.initializeFromFile(header, file);
// reconstruct root
int nextPageID = file.getNextPageID();
dirCapacity = nextPageID;
root = createNewDirectoryNode();
for(int i = 1; i < nextPageID; i++) {
FlatRStarTreeNode node = getNode(i);
root.addDirectoryEntry(createNewDirectoryEntry(node));
}
if(LOG.isDebugging()) {
LOG.debugFine("root: " + root + " with " + nextPageID + " leafNodes.");
}
}
/**
* Returns the root node of this RTree.
*
* @return the root node of this RTree
*/
@Override
public FlatRStarTreeNode getRoot() {
return root;
}
/**
* Returns the height of this FlatRTree.
*
* @return 2
*/
@Override
protected int computeHeight() {
return 2;
}
/**
* Performs a bulk load on this RTree with the specified data. Is called by
* the constructor and should be overwritten by subclasses if necessary.
*/
@Override
protected void bulkLoad(List<SpatialEntry> spatialObjects) {
if(!initialized) {
initialize(spatialObjects.get(0));
}
// create leaf nodes
getFile().setNextPageID(getRootID() + 1);
List<SpatialEntry> nodes = createBulkLeafNodes(spatialObjects);
int numNodes = nodes.size();
if(LOG.isDebugging()) {
LOG.debugFine(" numLeafNodes = " + numNodes);
}
// create root
root = createNewDirectoryNode();
root.setPageID(getRootID());
for(SpatialEntry entry : nodes) {
root.addDirectoryEntry(entry);
}
numNodes++;
setHeight(2);
if(LOG.isDebugging()) {
StringBuilder msg = new StringBuilder();
msg.append(" root = ").append(getRoot());
msg.append("\n numNodes = ").append(numNodes);
msg.append("\n height = ").append(getHeight());
LOG.debugFine(msg.toString() + "\n");
}
doExtraIntegrityChecks();
}
@Override
protected void createEmptyRoot(SpatialEntry exampleLeaf) {
root = createNewDirectoryNode();
root.setPageID(getRootID());
getFile().setNextPageID(getRootID() + 1);
FlatRStarTreeNode leaf = createNewLeafNode();
writeNode(leaf);
ModifiableHyperBoundingBox mbr = new ModifiableHyperBoundingBox(new double[exampleLeaf.getDimensionality()], new double[exampleLeaf.getDimensionality()]);
root.addDirectoryEntry(new SpatialDirectoryEntry(leaf.getPageID(), mbr));
setHeight(2);
}
/**
* Returns true if in the specified node an overflow occurred, false
* otherwise.
*
* @param node the node to be tested for overflow
* @return true if in the specified node an overflow occurred, false otherwise
*/
@Override
protected boolean hasOverflow(FlatRStarTreeNode node) {
if(node.isLeaf()) {
return node.getNumEntries() == leafCapacity;
}
else if(node.getNumEntries() == node.getCapacity()) {
node.increaseEntries();
}
return false;
}
/**
* Returns true if in the specified node an underflow occurred, false
* otherwise.
*
* @param node the node to be tested for underflow
* @return true if in the specified node an underflow occurred, false
* otherwise
*/
@Override
protected boolean hasUnderflow(FlatRStarTreeNode node) {
if(node.isLeaf()) {
return node.getNumEntries() < leafMinimum;
}
else {
return false;
}
}
/**
* Creates a new leaf node with the specified capacity.
*
* @return a new leaf node
*/
@Override
protected FlatRStarTreeNode createNewLeafNode() {
return new FlatRStarTreeNode(leafCapacity, true);
}
/**
* Creates a new directory node with the specified capacity.
*
* @return a new directory node
*/
@Override
protected FlatRStarTreeNode createNewDirectoryNode() {
return new FlatRStarTreeNode(dirCapacity, false);
}
@Override
protected SpatialEntry createNewDirectoryEntry(FlatRStarTreeNode node) {
return new SpatialDirectoryEntry(node.getPageID(), node.computeMBR());
}
@Override
protected SpatialEntry createRootEntry() {
return new SpatialDirectoryEntry(0, null);
}
@Override
protected Logging getLogger() {
return LOG;
}
}
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