gernotbelger@9263: /** Copyright (C) 2017 by Bundesanstalt für Gewässerkunde
gernotbelger@9263:  * Software engineering by
gernotbelger@9263:  *  Björnsen Beratende Ingenieure GmbH
gernotbelger@9263:  *  Dr. Schumacher Ingenieurbüro für Wasser und Umwelt
gernotbelger@9263:  *
gernotbelger@9263:  * This file is Free Software under the GNU AGPL (>=v3)
gernotbelger@9263:  * and comes with ABSOLUTELY NO WARRANTY! Check out the
gernotbelger@9263:  * documentation coming with Dive4Elements River for details.
gernotbelger@9263:  */
gernotbelger@9263: package org.dive4elements.river.client.client.ui.chart;
gernotbelger@9263: 
gernotbelger@9263: import java.util.Set;
gernotbelger@9263: import java.util.SortedSet;
gernotbelger@9263: import java.util.TreeSet;
gernotbelger@9263: 
gernotbelger@9263: /**
gernotbelger@9263:  * Allows stepping through a list of distinct (known) values.
gernotbelger@9263:  *
gernotbelger@9263:  * @author Gernot Belger
gernotbelger@9263:  */
gernotbelger@9263: public class DistinctValuesNaviChartStepper implements INaviChartStepper {
gernotbelger@9263: 
gernotbelger@9263:     private final TreeSet<Double> validSteps = new TreeSet<Double>();
gernotbelger@9263: 
gernotbelger@9263:     private double currentKm;
gernotbelger@9263: 
gernotbelger@9263:     public DistinctValuesNaviChartStepper(final Set<Double> validKms) {
gernotbelger@9263:         this.validSteps.addAll(validKms);
gernotbelger@9263: 
gernotbelger@9263:         if (this.validSteps.isEmpty())
gernotbelger@9263:             this.validSteps.add(-1d);
gernotbelger@9263: 
gernotbelger@9263:         this.currentKm = this.validSteps.first();
gernotbelger@9263:     }
gernotbelger@9263: 
gernotbelger@9263:     @Override
gernotbelger@9263:     public double getCurrentKm() {
gernotbelger@9263:         return this.currentKm;
gernotbelger@9263:     }
gernotbelger@9263: 
gernotbelger@9263:     @Override
gernotbelger@9263:     public double stepForward() {
gernotbelger@9263:         this.currentKm = calculateStepFormward();
gernotbelger@9263:         return this.currentKm;
gernotbelger@9263:     }
gernotbelger@9263: 
gernotbelger@9263:     private double calculateStepFormward() {
gernotbelger@9263:         // REMARK: can't use higher due to gwt bug
gernotbelger@9263:         // final Double next = this.validSteps.higher(this.currentKm);
gernotbelger@9263: 
gernotbelger@9263:         // REMAREK: add a bit, because tailSet is inclusive
gernotbelger@9263:         final SortedSet<Double> tailSet = this.validSteps.tailSet(this.currentKm + 1e-6);
gernotbelger@9263:         final Double next = tailSet.isEmpty() ? null : tailSet.first();
gernotbelger@9263: 
gernotbelger@9263:         if (next != null)
gernotbelger@9263:             return next;
gernotbelger@9263: 
gernotbelger@9263:         return this.validSteps.last();
gernotbelger@9263:     }
gernotbelger@9263: 
gernotbelger@9263:     @Override
gernotbelger@9263:     public double stepBackward() {
gernotbelger@9263:         this.currentKm = calculateStepBackward();
gernotbelger@9263:         return this.currentKm;
gernotbelger@9263:     }
gernotbelger@9263: 
gernotbelger@9263:     private double calculateStepBackward() {
gernotbelger@9263:         // REMARK: can't use lower due to gwt bug
gernotbelger@9263:         // final Double prev = this.validSteps.lower(this.currentKm);
gernotbelger@9263: 
gernotbelger@9263:         final SortedSet<Double> headSet = this.validSteps.headSet(this.currentKm);
gernotbelger@9263:         final Double prev = headSet.isEmpty() ? null : headSet.last();
gernotbelger@9263: 
gernotbelger@9263:         if (prev != null)
gernotbelger@9263:             return prev;
gernotbelger@9263: 
gernotbelger@9263:         return this.validSteps.first();
gernotbelger@9263:     }
gernotbelger@9263: 
gernotbelger@9263:     @Override
gernotbelger@9263:     public double setValidCurrentKm(final double currentKm) {
gernotbelger@9263:         this.currentKm = calculateValidCurrentKm(currentKm);
gernotbelger@9263:         return this.currentKm;
gernotbelger@9263:     }
gernotbelger@9263: 
gernotbelger@9263:     private double calculateValidCurrentKm(final double newKm) {
gernotbelger@9263: 
gernotbelger@9263:         if (this.validSteps.contains(newKm)) {
gernotbelger@9263:             /* special case, and because headSet() is not inclusive */
gernotbelger@9263:             return newKm;
gernotbelger@9263:         }
gernotbelger@9263: 
gernotbelger@9263:         final SortedSet<Double> headSet = this.validSteps.headSet(newKm);
gernotbelger@9263:         final SortedSet<Double> tailSet = this.validSteps.tailSet(newKm);
gernotbelger@9263: 
gernotbelger@9263:         // REMARK: can't use floor/ceiling because of gwt bug
gernotbelger@9263:         // final Double floor = this.validSteps.floor(currentKm);
gernotbelger@9263:         // final Double ceiling = this.validSteps.ceiling(currentKm);
gernotbelger@9263:         final Double floor = headSet.isEmpty() ? null : headSet.last();
gernotbelger@9263:         final Double ceiling = tailSet.isEmpty() ? null : tailSet.first();
gernotbelger@9263: 
gernotbelger@9263:         if (floor != null && ceiling == null)
gernotbelger@9263:             return floor;
gernotbelger@9263: 
gernotbelger@9263:         if (floor == null && ceiling != null)
gernotbelger@9263:             return ceiling;
gernotbelger@9263: 
gernotbelger@9263:         if (floor == null && ceiling == null) {
gernotbelger@9263:             /* should never happen as validKms is never empty */
gernotbelger@9263:             return this.currentKm;
gernotbelger@9263:         }
gernotbelger@9263: 
gernotbelger@9263:         if (floor == null || ceiling == null) {
gernotbelger@9263:             /* will never happen, but makes the NullPointer access checker happy, else we get warnings in the folowing code */
gernotbelger@9263:             return this.currentKm;
gernotbelger@9263:         }
gernotbelger@9263: 
gernotbelger@9263:         /* both not null; find nearest */
gernotbelger@9263:         final double floorDiff = Math.abs(newKm - floor);
gernotbelger@9263:         final double ceilingDiff = Math.abs(newKm - ceiling);
gernotbelger@9263:         if (floorDiff < ceilingDiff)
gernotbelger@9263:             return floor;
gernotbelger@9263: 
gernotbelger@9263:         return ceiling;
gernotbelger@9263:     }
gernotbelger@9263: }