/*
 * The Unified Mapping Platform (JUMP) is an extensible, interactive GUI 
 * for visualizing and manipulating spatial features with geometry and attributes.
 *
 * Copyright (C) 2003 Vivid Solutions
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; 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.jump.feature;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;

import com.vividsolutions.jts.geom.Geometry;

/**
 * Useful utility functions for working with Features.
 * @see Feature
 */
public class FeatureUtil {
	
	/**
	 * Creates a new Feature from the given Geometry, with nominal values for
	 * the attributes.
	 * @param g the Geometry to convert
	 * @param schema metadata for the Feature to create
	 * @return a new Feature containing the Geometry and default values for the
	 * attributes
	 */
	public static Feature toFeature(Geometry g, FeatureSchema schema) {
		BasicFeature feature = new BasicFeature(schema);
	    feature.setGeometry(g);
	    feature.setModified(true);
	    return feature;
	}

    /**
     * Returns the n Geometries extracted from the given n Features
     */
	public static List toGeometries(Collection features) {
	    ArrayList list = new ArrayList();
	
	    for (Iterator i = features.iterator(); i.hasNext();) {
	        Feature feature = (Feature) i.next();
	        list.add(feature.getGeometry());
	    }
	
	    return list;
	}
	
    /**
     * Compares two Features for order based on their feature ID.
     * @see Feature#getID()
     */
	public static class IDComparator implements Comparator {
		public int compare(Object o1, Object o2) {
			Feature f1 = (Feature) o1;
			Feature f2 = (Feature) o2;

			if (f1.getID() < f2.getID()) {
				return -1;
			}

			if (f1.getID() > f2.getID()) {
				return 1;
			}

			return 0;
		}
	}	
	
	private static int lastID = 0;
	
    /**
     * Increments and returns the feature-ID counter
     * @see Feature#getID()
     */
	public static int nextID() { return ++lastID; }

    /**
     * Although Feature implements Cloneable, this method is useful
     * when the two Features are implemented with different classes.
     */
    public static void copyAttributes(Feature a, Feature b) {
        for (int i = 0; i < a.getSchema().getAttributeCount(); i++) {
            b.setAttribute(i, a.getAttribute(i));
        }
    }

    /**
	 * Returns whether all attributes are null (other than the Geometry
	 * attribute, which is not checked)
	 */
    public static boolean areAllNonSpatialAttributesNull(Feature feature) {
        for (int i = 0; i < feature.getSchema().getAttributeCount(); i++) {
            if (AttributeType.GEOMETRY == feature.getSchema().getAttributeType(i)) {
                continue;
            }
            if (feature.getAttribute(i) != null) {
                return false;
            }
        }
        return true;
    }	
	
}