package de.lmu.ifi.dbs.elki.index.tree.spatial.rstarvariants;
/*
This file is part of ELKI:
Environment for Developing KDD-Applications Supported by Index-Structures
Copyright (C) 2012
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.ObjectInput;
import java.io.ObjectOutput;
import java.util.logging.Logger;
import de.lmu.ifi.dbs.elki.data.HyperBoundingBox;
import de.lmu.ifi.dbs.elki.data.ModifiableHyperBoundingBox;
import de.lmu.ifi.dbs.elki.data.spatial.SpatialComparable;
import de.lmu.ifi.dbs.elki.data.spatial.SpatialUtil;
import de.lmu.ifi.dbs.elki.index.tree.AbstractNode;
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.SpatialNode;
import de.lmu.ifi.dbs.elki.index.tree.spatial.SpatialPointLeafEntry;
import de.lmu.ifi.dbs.elki.logging.LoggingConfiguration;
/**
* Abstract superclass for nodes in a R*-Tree.
*
* @author Elke Achtert
* @param <N> Node type
* @param <E> Entry type
*/
public abstract class AbstractRStarTreeNode<N extends AbstractRStarTreeNode<N, E>, E extends SpatialEntry> extends AbstractNode<E> implements SpatialNode<N, E> {
/**
* Empty constructor for Externalizable interface.
*/
public AbstractRStarTreeNode() {
super();
}
/**
* Creates a new AbstractRStarTreeNode with the specified parameters.
*
* @param capacity the capacity (maximum number of entries plus 1 for
* overflow) of this node
* @param isLeaf indicates whether this node is a leaf node
* @param eclass Entry class, to initialize array storage
*/
public AbstractRStarTreeNode(int capacity, boolean isLeaf, Class<? super E> eclass) {
super(capacity, isLeaf, eclass);
}
/**
* Recomputing the MBR is rather expensive.
*
* @return MBR
*/
public ModifiableHyperBoundingBox computeMBR() {
E firstEntry = getEntry(0);
if(firstEntry == null) {
return null;
}
// Note: we deliberately get a cloned copy here, since we will modify it.
ModifiableHyperBoundingBox mbr = new ModifiableHyperBoundingBox(firstEntry);
for(int i = 1; i < numEntries; i++) {
mbr.extend(getEntry(i));
}
return mbr;
}
/**
* Adjusts the parameters of the entry representing this node.
*
* @param entry the entry representing this node
*/
public boolean adjustEntry(E entry) {
final SpatialDirectoryEntry se = (SpatialDirectoryEntry) entry;
final ModifiableHyperBoundingBox mbr = computeMBR();
boolean changed = false;
if(se.hasMBR()) {
final int dim = se.getDimensionality();
// Test for changes
for(int i = 1; i <= dim; i++) {
if(Math.abs(se.getMin(i) - mbr.getMin(i)) > Float.MIN_NORMAL) {
changed = true;
break;
}
if(Math.abs(se.getMax(i) - mbr.getMax(i)) > Float.MIN_NORMAL) {
changed = true;
break;
}
}
}
else { // No preexisting MBR.
changed = true;
}
if(changed) {
se.setMBR(mbr);
}
return changed;
}
/**
* Adjusts the parameters of the entry representing this node. Only applicable
* if one object was inserted or the size of an existing node increased.
*
* @param entry the entry representing this node
* @param responsibleMBR the MBR of the object or node which is responsible
* for the call of the method
* @return true when the entry has changed
*/
public boolean adjustEntryIncremental(E entry, SpatialComparable responsibleMBR) {
return ((SpatialDirectoryEntry) entry).extendMBR(responsibleMBR);
}
/**
* Tests this node (for debugging purposes).
*/
@SuppressWarnings("unchecked")
public final void integrityCheck(AbstractRStarTree<N, E> tree) {
// leaf node
if(isLeaf()) {
for(int i = 0; i < getCapacity(); i++) {
E e = getEntry(i);
if(i < getNumEntries() && e == null) {
throw new RuntimeException("i < numEntries && entry == null");
}
if(i >= getNumEntries() && e != null) {
throw new RuntimeException("i >= numEntries && entry != null");
}
}
}
// dir node
else {
N tmp = tree.getNode(getEntry(0));
boolean childIsLeaf = tmp.isLeaf();
for(int i = 0; i < getCapacity(); i++) {
E e = getEntry(i);
if(i < getNumEntries() && e == null) {
throw new RuntimeException("i < numEntries && entry == null");
}
if(i >= getNumEntries() && e != null) {
throw new RuntimeException("i >= numEntries && entry != null");
}
if(e != null) {
N node = tree.getNode(e);
if(childIsLeaf && !node.isLeaf()) {
for(int k = 0; k < getNumEntries(); k++) {
tree.getNode(getEntry(k));
}
throw new RuntimeException("Wrong Child in " + this + " at " + i);
}
if(!childIsLeaf && node.isLeaf()) {
throw new RuntimeException("Wrong Child: child id no leaf, but node is leaf!");
}
node.integrityCheckParameters((N) this, i);
node.integrityCheck(tree);
}
}
if(LoggingConfiguration.DEBUG) {
Logger.getLogger(this.getClass().getName()).fine("DirNode " + getPageID() + " ok!");
}
}
}
/**
* Tests, if the parameters of the entry representing this node, are correctly
* set. Subclasses may need to overwrite this method.
*
* @param parent the parent holding the entry representing this node
* @param index the index of the entry in the parents child array
*/
protected void integrityCheckParameters(N parent, int index) {
// test if mbr is correctly set
E entry = parent.getEntry(index);
HyperBoundingBox mbr = computeMBR();
if(/* entry.getMBR() == null && */mbr == null) {
return;
}
if(!SpatialUtil.equals(entry, mbr)) {
String soll = mbr.toString();
String ist = new HyperBoundingBox(entry).toString();
throw new RuntimeException("Wrong MBR in node " + parent.getPageID() + " at index " + index + " (child " + entry + ")" + "\nsoll: " + soll + ",\n ist: " + ist);
}
}
/**
* Calls the super method and writes the id of this node, the numEntries and
* the entries array to the specified stream.
*/
@Override
public void writeExternal(ObjectOutput out) throws IOException {
super.writeExternal(out);
// TODO: do we need to write/read the capacity?
out.writeInt(entries.length);
for(E entry : entries) {
if(entry == null) {
break;
}
entry.writeExternal(out);
}
}
/**
* Reads the id of this node, the numEntries and the entries array from the
* specified stream.
*
* @param in the stream to read data from in order to restore the object
* @throws java.io.IOException if I/O errors occur
* @throws ClassNotFoundException If the class for an object being restored
* cannot be found.
*/
@Override
@SuppressWarnings("unchecked")
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
super.readExternal(in);
// TODO: do we need to write/read the capacity?
final int capacity = in.readInt();
if(isLeaf()) {
entries = (E[]) new SpatialPointLeafEntry[capacity];
for(int i = 0; i < numEntries; i++) {
SpatialPointLeafEntry s = new SpatialPointLeafEntry();
s.readExternal(in);
entries[i] = (E) s;
}
}
else {
entries = (E[]) new SpatialDirectoryEntry[capacity];
for(int i = 0; i < numEntries; i++) {
SpatialDirectoryEntry s = new SpatialDirectoryEntry();
s.readExternal(in);
entries[i] = (E) s;
}
}
}
}