/*
* 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.geom;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* Iterates over all {@link Geometry}s in a {@link GeometryCollection}.
* . Implements a pre-order depth-first traversal of the <code>GeometryCollection</code>
* (which may be nested). The original <code>GeometryCollection</code> is
* returned as well (as the first object), as are all sub-collections. It is
* simple to ignore the <code>GeometryCollection</code> objects if they are not
* needed.
*
*@version 1.7
*/
public class GeometryCollectionIterator implements Iterator {
/**
* The <code>GeometryCollection</code> being iterated over.
*/
private Geometry parent;
/**
* Indicates whether or not the first element (the <code>GeometryCollection</code>
* ) has been returned.
*/
private boolean atStart;
/**
* The number of <code>Geometry</code>s in the the <code>GeometryCollection</code>
* .
*/
private int max;
/**
* The index of the <code>Geometry</code> that will be returned when <code>next</code>
* is called.
*/
private int index;
/**
* The iterator over a nested <code>GeometryCollection</code>, or <code>null</code>
* if this <code>GeometryCollectionIterator</code> is not currently iterating
* over a nested <code>GeometryCollection</code>.
*/
private GeometryCollectionIterator subcollectionIterator;
/**
* Constructs an iterator over the given <code>GeometryCollection</code>.
*
*@param parent the collection over which to iterate; also, the first
* element returned by the iterator.
*/
public GeometryCollectionIterator(Geometry parent) {
this.parent = parent;
atStart = true;
index = 0;
max = parent.getNumGeometries();
}
public boolean hasNext() {
if (atStart) {
return true;
}
if (subcollectionIterator != null) {
if (subcollectionIterator.hasNext()) {
return true;
}
subcollectionIterator = null;
}
if (index >= max) {
return false;
}
return true;
}
public Object next() {
// the parent GeometryCollection is the first object returned
if (atStart) {
atStart = false;
return parent;
}
if (subcollectionIterator != null) {
if (subcollectionIterator.hasNext()) {
return subcollectionIterator.next();
}
else {
subcollectionIterator = null;
}
}
if (index >= max) {
throw new NoSuchElementException();
}
Geometry obj = parent.getGeometryN(index++);
if (obj instanceof GeometryCollection) {
subcollectionIterator = new GeometryCollectionIterator((GeometryCollection) obj);
// there will always be at least one element in the sub-collection
return subcollectionIterator.next();
}
return obj;
}
/**
* Not implemented.
*
*@throws UnsupportedOperationException This method is not implemented.
*/
public void remove() {
throw new UnsupportedOperationException(getClass().getName());
}
}