| gvSIG desktop 1

/*

 * Copyright (c) 2005 by L. Paul Chew.

 * 

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, subject to the following 

 * conditions:

 *

 * The above copyright notice and this permission notice shall be included 

 * in all copies or substantial portions of the Software.

 * 

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 

 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 

 * DEALINGS IN THE SOFTWARE.

 */

package com.iver.cit.gvsig.topology.triangulation;

import java.util.AbstractSet;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collection;

import java.util.Collections;

import java.util.HashSet;

import java.util.Iterator;

import java.util.LinkedList;

import java.util.List;

import java.util.Set;

/**

 * A Simplex is an immutable set of vertices (usually Pnts).

 * 

 * @author Paul Chew

 * 

 * Created July 2005. Derived from an earlier, messier version.

 */

public class Simplex extends AbstractSet implements Set {

    private List vertices;                  // The simplex's vertices

    private long idNumber;                  // The id number

    private static long idGenerator = 0;    // Used to create id numbers

    public static boolean moreInfo = false; // True iff more info in toString

    /**

     * Constructor.

     * @param collection a Collection holding the Simplex vertices

     * @throws IllegalArgumentException if there are duplicate vertices

     */

    public Simplex (Collection collection) {

        this.vertices = Collections.unmodifiableList(new ArrayList(collection));

        this.idNumber = idGenerator++;

        Set noDups = new HashSet(this);

        if (noDups.size() != this.vertices.size())

            throw new IllegalArgumentException("Duplicate vertices in Simplex");

    }

    /**

     * Constructor.

     * @param vertices the vertices of the Simplex.

     * @throws IllegalArgumentException if there are duplicate vertices

     */

    public Simplex (Object[] vertices) {

        this(Arrays.asList(vertices));

    }

    /**

     * String representation.

     * @return the String representation of this Simplex

     */

    public String toString () {

        if (!moreInfo) return "Simplex" + idNumber;

        return "Simplex" + idNumber + super.toString();

    }

    /**

     * Dimension of the Simplex.

     * @return dimension of Simplex (one less than number of vertices)

     */

    public int dimension () {

        return this.vertices.size() - 1;

    }

    /**

     * True iff simplices are neighbors.

     * Two simplices are neighbors if they are the same dimension and they share

     * a facet.

     * @param simplex the other Simplex

     * @return true iff this Simplex is a neighbor of simplex

     */

    public boolean isNeighbor (Simplex simplex) {

        HashSet h = new HashSet(this);

        h.removeAll(simplex);

        return (this.size() == simplex.size()) && (h.size() == 1);

    }

    /**

     * Report the facets of this Simplex.

     * Each facet is a set of vertices.

     * @return an Iterable for the facets of this Simplex

     */

    public List facets () {

        List theFacets = new LinkedList();

        for (Iterator it = this.iterator(); it.hasNext();) {

            Object v = it.next();

            Set facet = new HashSet(this);

            facet.remove(v);

            theFacets.add(facet);

        }

        return theFacets;

    }

    /**

     * Report the boundary of a Set of Simplices.

     * The boundary is a Set of facets where each facet is a Set of vertices.

     * @return an Iterator for the facets that make up the boundary

     */

    public static Set boundary (Set simplexSet) {

        Set theBoundary = new HashSet();

        for (Iterator it = simplexSet.iterator(); it.hasNext();) {

            Simplex simplex = (Simplex) it.next();

            for (Iterator otherIt = simplex.facets().iterator(); otherIt.hasNext();) {

                Set facet = (Set) otherIt.next();

                if (theBoundary.contains(facet)) theBoundary.remove(facet);

                else theBoundary.add(facet);

            }

        }

        return theBoundary;

    }

    /* Remaining methods are those required by AbstractSet */

    /**

     * @return Iterator for Simplex's vertices.

     */

    public Iterator iterator () {

        return this.vertices.iterator();

    }

    /**

     * @return the size (# of vertices) of this Simplex

     */

    public int size () {

        return this.vertices.size();

    }

    /**

     * @return the hashCode of this Simplex

     */

    public int hashCode () {

        return (int)(idNumber^(idNumber>>>32));

    }

    /**

     * We want to allow for different simplices that share the same vertex set.

     * @return true for equal Simplices

     */

    public boolean equals (Object o) {

        return (this == o);

    }

}