/*
* The JTS Topology Suite is a collection of Java classes that
* implement the fundamental operations required to validate a given
* geo-spatial data set to a known topological specification.
*
* Copyright (C) 2001 Vivid Solutions
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* For more information, contact:
*
* Vivid Solutions
* Suite #1A
* 2328 Government Street
* Victoria BC V8T 5G5
* Canada
*
* (250)385-6040
* www.vividsolutions.com
*/
package com.vividsolutions.jts.index.quadtree;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.index.ItemVisitor;
/**
* The base class for nodes in a {@link Quadtree}.
*
* @version 1.7
*/
public abstract class NodeBase implements Serializable {
//DEBUG private static int itemCount = 0; // debugging
/**
* Gets the index of the subquad that wholly contains the given envelope.
* If none does, returns -1.
*
* @return the index of the subquad that wholly contains the given envelope
* or -1 if no subquad wholly contains the envelope
*/
public static int getSubnodeIndex(Envelope env, double centrex, double centrey)
{
int subnodeIndex = -1;
if (env.getMinX() >= centrex) {
if (env.getMinY() >= centrey) subnodeIndex = 3;
if (env.getMaxY() <= centrey) subnodeIndex = 1;
}
if (env.getMaxX() <= centrex) {
if (env.getMinY() >= centrey) subnodeIndex = 2;
if (env.getMaxY() <= centrey) subnodeIndex = 0;
}
return subnodeIndex;
}
protected List items = new ArrayList();
/**
* subquads are numbered as follows:
* <pre>
* 2 | 3
* --+--
* 0 | 1
* </pre>
*/
protected Node[] subnode = new Node[4];
public NodeBase() {
}
public List getItems() { return items; }
public boolean hasItems() { return ! items.isEmpty(); }
public void add(Object item)
{
items.add(item);
//DEBUG itemCount++;
//DEBUG System.out.print(itemCount);
}
/**
* Removes a single item from this subtree.
*
* @param itemEnv the envelope containing the item
* @param item the item to remove
* @return <code>true</code> if the item was found and removed
*/
public boolean remove(Envelope itemEnv, Object item)
{
// use envelope to restrict nodes scanned
if (! isSearchMatch(itemEnv))
return false;
boolean found = false;
for (int i = 0; i < 4; i++) {
if (subnode[i] != null) {
found = subnode[i].remove(itemEnv, item);
if (found) {
// trim subtree if empty
if (subnode[i].isPrunable())
subnode[i] = null;
break;
}
}
}
// if item was found lower down, don't need to search for it here
if (found) return found;
// otherwise, try and remove the item from the list of items in this node
found = items.remove(item);
return found;
}
public boolean isPrunable()
{
return ! (hasChildren() || hasItems());
}
public boolean hasChildren()
{
for (int i = 0; i < 4; i++) {
if (subnode[i] != null)
return true;
}
return false;
}
public boolean isEmpty()
{
boolean isEmpty = true;
if (! items.isEmpty()) isEmpty = false;
for (int i = 0; i < 4; i++) {
if (subnode[i] != null) {
if (! subnode[i].isEmpty() )
isEmpty = false;
}
}
return isEmpty;
}
//<<TODO:RENAME?>> Sounds like this method adds resultItems to items
//(like List#addAll). Perhaps it should be renamed to "addAllItemsTo" [Jon Aquino]
public List addAllItems(List resultItems)
{
// this node may have items as well as subnodes (since items may not
// be wholely contained in any single subnode
resultItems.addAll(this.items);
for (int i = 0; i < 4; i++) {
if (subnode[i] != null) {
subnode[i].addAllItems(resultItems);
}
}
return resultItems;
}
protected abstract boolean isSearchMatch(Envelope searchEnv);
public void addAllItemsFromOverlapping(Envelope searchEnv, List resultItems)
{
if (! isSearchMatch(searchEnv))
return;
// this node may have items as well as subnodes (since items may not
// be wholely contained in any single subnode
resultItems.addAll(items);
for (int i = 0; i < 4; i++) {
if (subnode[i] != null) {
subnode[i].addAllItemsFromOverlapping(searchEnv, resultItems);
}
}
}
public void visit(Envelope searchEnv, ItemVisitor visitor)
{
if (! isSearchMatch(searchEnv))
return;
// this node may have items as well as subnodes (since items may not
// be wholely contained in any single subnode
visitItems(searchEnv, visitor);
for (int i = 0; i < 4; i++) {
if (subnode[i] != null) {
subnode[i].visit(searchEnv, visitor);
}
}
}
private void visitItems(Envelope searchEnv, ItemVisitor visitor)
{
// would be nice to filter items based on search envelope, but can't until they contain an envelope
for (Iterator i = items.iterator(); i.hasNext(); ) {
visitor.visitItem(i.next());
}
}
//<<TODO:RENAME?>> In Samet's terminology, I think what we're returning here is
//actually level+1 rather than depth. (See p. 4 of his book) [Jon Aquino]
int depth()
{
int maxSubDepth = 0;
for (int i = 0; i < 4; i++) {
if (subnode[i] != null) {
int sqd = subnode[i].depth();
if (sqd > maxSubDepth)
maxSubDepth = sqd;
}
}
return maxSubDepth + 1;
}
int size()
{
int subSize = 0;
for (int i = 0; i < 4; i++) {
if (subnode[i] != null) {
subSize += subnode[i].size();
}
}
return subSize + items.size();
}
int getNodeCount()
{
int subSize = 0;
for (int i = 0; i < 4; i++) {
if (subnode[i] != null) {
subSize += subnode[i].size();
}
}
return subSize + 1;
}
}