001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.math3.geometry.euclidean.oned;
018    
019    import org.apache.commons.math3.geometry.Vector;
020    import org.apache.commons.math3.geometry.partitioning.Hyperplane;
021    
022    /** This class represents a 1D oriented hyperplane.
023     * <p>An hyperplane in 1D is a simple point, its orientation being a
024     * boolean.</p>
025     * <p>Instances of this class are guaranteed to be immutable.</p>
026     * @version $Id: OrientedPoint.java 1416643 2012-12-03 19:37:14Z tn $
027     * @since 3.0
028     */
029    public class OrientedPoint implements Hyperplane<Euclidean1D> {
030    
031        /** Vector location. */
032        private Vector1D location;
033    
034        /** Orientation. */
035        private boolean direct;
036    
037        /** Simple constructor.
038         * @param location location of the hyperplane
039         * @param direct if true, the plus side of the hyperplane is towards
040         * abscissas greater than {@code location}
041         */
042        public OrientedPoint(final Vector1D location, final boolean direct) {
043            this.location = location;
044            this.direct   = direct;
045        }
046    
047        /** Copy the instance.
048         * <p>Since instances are immutable, this method directly returns
049         * the instance.</p>
050         * @return the instance itself
051         */
052        public OrientedPoint copySelf() {
053            return this;
054        }
055    
056        /** {@inheritDoc} */
057        public double getOffset(final Vector<Euclidean1D> point) {
058            final double delta = ((Vector1D) point).getX() - location.getX();
059            return direct ? delta : -delta;
060        }
061    
062        /** Build a region covering the whole hyperplane.
063         * <p>Since this class represent zero dimension spaces which does
064         * not have lower dimension sub-spaces, this method returns a dummy
065         * implementation of a {@link
066         * org.apache.commons.math3.geometry.partitioning.SubHyperplane SubHyperplane}.
067         * This implementation is only used to allow the {@link
068         * org.apache.commons.math3.geometry.partitioning.SubHyperplane
069         * SubHyperplane} class implementation to work properly, it should
070         * <em>not</em> be used otherwise.</p>
071         * @return a dummy sub hyperplane
072         */
073        public SubOrientedPoint wholeHyperplane() {
074            return new SubOrientedPoint(this, null);
075        }
076    
077        /** Build a region covering the whole space.
078         * @return a region containing the instance (really an {@link
079         * IntervalsSet IntervalsSet} instance)
080         */
081        public IntervalsSet wholeSpace() {
082            return new IntervalsSet();
083        }
084    
085        /** {@inheritDoc} */
086        public boolean sameOrientationAs(final Hyperplane<Euclidean1D> other) {
087            return !(direct ^ ((OrientedPoint) other).direct);
088        }
089    
090        /** Get the hyperplane location on the real line.
091         * @return the hyperplane location
092         */
093        public Vector1D getLocation() {
094            return location;
095        }
096    
097        /** Check if the hyperplane orientation is direct.
098         * @return true if the plus side of the hyperplane is towards
099         * abscissae greater than hyperplane location
100         */
101        public boolean isDirect() {
102            return direct;
103        }
104    
105        /** Revert the instance.
106         */
107        public void revertSelf() {
108            direct = !direct;
109        }
110    
111    }