AbstractPolygonHoleCommand.java

//$HeadURL$
/*----------------------------------------------------------------------------
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 Copyright (C) 2001-2009 by:
 - Department of Geography, University of Bonn -
 and
 - lat/lon GmbH -

 This library is free software; you can redistribute it and/or modify it under
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 any later version.
 This library is distributed in the hope that it will be useful, but WITHOUT
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 Germany
 http://lat-lon.de/

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package org.deegree.igeo.commands.digitize;

import org.deegree.kernel.AbstractCommand;
import org.deegree.model.spatialschema.JTSAdapter;
import org.deegree.model.spatialschema.Position;

import com.vividsolutions.jts.algorithm.CGAlgorithms;

/**
 * TODO add class documentation here
 * 
 * @author <a href="mailto:name@deegree.org">Andreas Poth</a>
 * @author last edited by: $Author$
 * 
 * @version $Revision$, $Date$
 */
abstract class AbstractPolygonHoleCommand extends AbstractCommand {
    /**
     * 
     * @param ring
     * @return true if an array of passed {@link Position} forms a clockwise orientated ring
     */
    protected static boolean isClockwise( Position[] ring ) {
        return !CGAlgorithms.isCCW( JTSAdapter.export( ring ).getCoordinates() );
    }
    
    /**
     * inverts the order of the positions of a ring
     * 
     * @param inner
     */
    protected static void invertPositionOrder( Position[] inner ) {
        for ( int i = 0; i < inner.length / 2; i++ ) {
            Position tmp = inner[i];
            inner[i] = inner[inner.length - 1 - i];
            inner[inner.length - 1 - i] = tmp;
        }
    }
    
    /*
     * (non-Javadoc)
     * 
     * @see org.deegree.kernel.Command#isUndoSupported()
     */
    public boolean isUndoSupported() {
        return true;
    }
}