Introduction to Java Programming（10th Edition）课后练习答案

package ToolKit; import javafx.animation.PathTransition; import javafx.collections.ObservableList; import javafx.scene.layout.Pane; import javafx.scene.paint.Color; import javafx.scene.shape.Circle; import javafx.scene.shape.Line; import javafx.scene.shape.Polyline; import javafx.util.Duration; import java.util.ArrayList; /** * * Chapter 15 Exercise 15 * Created by luizsa on 9/22/14. */ public class TBeanMachinePane extends Pane { // Bean machine measurements double w = 800; // Pane default width double h = 800; // Pane default height double gap; // distance gap between slot lines double radius; // peg's radius double dropX; // Drop ball starting x point double dropY; // Drop ball starting y point // int numOfSlots; // numbers of slots // Line's sequence drawn matters Line baseLine; Line leftSLine; // left side line (bottom left) Line rightSLine; // right side line (bottom right) Line[] cSlotLines; // center slot lines Line midLeftSLine; // middle left line Line midRightSLine; // middle right line Line topLeftSLine; // top left line Line topRightSLine; // top right line // Triangle pegs Circle[] pegs; // PEEGGSSSSS // Dropped balls ArrayList<Circle> balls; ArrayList<Circle> fineshedBalls; ArrayList<Polyline> ballPaths; // Animation ArrayList<PathTransition> mPathTransitions = new ArrayList<>(); private TBeanMachinePane() { baseLine = new Line(); baseLine.translateYProperty().bind(translateXProperty()); leftSLine = new Line(); rightSLine = new Line(); midLeftSLine = new Line(); midRightSLine = new Line(); topLeftSLine = new Line(); topRightSLine = new Line(); balls = new ArrayList<>(); fineshedBalls = new ArrayList<>(); ballPaths = new ArrayList<>(); } public TBeanMachinePane(int slots, double width, double height) { this(); initSlotLinesAndPegs(slots); // All layout nodes are initialized after this point numOfSlots = slots; setMinWidth(w = width); setMinHeight(h = height); setMaxSize(width, height); drawLayout(); addLayoutShapes(); } public void dropBall() { Circle ball = new Circle(dropX, dropY, radius); Polyline polyline = generatePath(); ObservableList<Double> list = polyline.getPoints(); double x = list.get(list.size() - 2); double y = list.get(list.size() - 1); fineshedBalls.add(new Circle(x, y, radius)); ballPaths.add(polyline); balls.add(ball); PathTransition path = new PathTransition(Duration.seconds(8), polyline, ball); mPathTransitions.add(path); path.setDelay(Duration.seconds(mPathTransitions.size())); getChildren().addAll(ball); //getChildren().addAll(polyline); path.play(); } private Polyline generatePath() { // dropped ball's beginning x and y point final int X = 0; final int Y = 1; double[] p = new double[]{dropX, dropY }; // the polyline will track the ball's path Polyline polyline = new Polyline(); ObservableList<Double> list = polyline.getPoints(); // Adding start point to the polyline list.addAll(p[X], p[Y]); // While the ball hasn't reached the end while (!isAtEnd(p[Y]) ) { // while the ball hasn't hit a boundary: keep falling... if (!hasBouncedOnPeg(p[X], p[Y]) && !hasBouncedOnBall(p[X], p[Y])) { p[Y] = moveDown(p[Y]); list.addAll(p[X], p[Y]); } // If the ball didn't bounce on another ball else if (hasBouncedOnPeg(p[X], p[Y]) || hasBouncedOnBall(p[X], p[Y])){ // If both sides are clear than make a random turn if (isClearLeft(p[X], p[Y]) && isClearRight(p[X], p[Y])) { p = ((int) (Math.random() * 2) == 1) ? rightArc(list, p[X], p[Y]) : leftArc(list, p[X], p[Y]); } // else if left side is clear make a left turn else if (isClearLeft(p[X], p[Y])) { p = leftArc(list, p[X], p[Y]); } // else if right side is clear make a right turn else if (isClearRight(p[X], p[Y])) { p = rightArc(list, p[X], p[Y]); } else { // if statement reaches here its a dead end break; } } } return polyline; } private boolean hasBouncedOnPeg(double x, double y) { for (Circle c : pegs) { if (c.contains(x, y + radius * 1.59999999)) { //getChildren().add(new Circle(x, y + radius * 2, 1)); return true; } } return false; } private double[] rightArc(ObservableList<Double> list, double startX, double startY) { double angle = 90; double x = 0; double y = 0; double arcRadius = radius * 2; for (int i = 0; i < 90; i++) { x = startX + arcRadius * Math.cos(Math.toRadians(angle)); y = (startY + arcRadius) - arcRadius * Math.sin(Math.toRadians(angle)); list.addAll(x,y); angle--; } return new double[]{x,y}; } private double[] leftArc(ObservableList<Double> list, double startX, double startY) { double angle = 90; double x = 0; double y = 0; double arcRadius = radius * 2; for (int i = 0; i < 90; i++) { x = startX + arcRadius * Math.cos(Math.toRadians(angle)); y = (startY + arcRadius) - arcRadius * Math.sin(Math.toRadians(angle)); list.addAll(x,y); angle++; } return new double[]{x,y}; } private boolean isClearLeft(double x, double y) { double limitX = x - radius * 2; if (limitX < baseLine.getStartX()) return false; for (Circle peg : pegs) { if (peg.contains(limitX, y) || !isInsideBeanMachine(limitX, y)) { return false; } } for (Circle c : balls) { if (c.contains(limitX, y) || !isInsideBeanMachine(limitX, y)) { return false; } } return true; } private boolean isClearRight(double x, double y) { double limitX = x + radius * 2; if (limitX > baseLine.getEndX()) return false; for (Circle peg : pegs) { if (peg.contains(limitX, y) || !isInsideBeanMachine(limitX, y)) { return false; } } for (Circle c : balls) { if (c.contains(limitX, y) || !isInsideBeanMachine(limitX, y)) { return false; } } return true; } private boolean isInsideBeanMachine(double x, double y) { if (y < pegs[pegs.length - 1].getCenterY()) return true; MyPoint p1 = new MyPoint(leftSLine.getEndX(), leftSLine.getEndY()); MyPoint p2 = new MyPoint(rightSLine.getEndX(), rightSLine.getEndY()); MyPoint p3 = new MyPoint( pegs[pegs.length - 1].getCenterX(), pegs[pegs.length - 1].getCenterY()); return (new Triangle2D(p1, p2, p3).contains(x, y)); } private boolean isAtEnd(double y) { return y >= baseLine.getEndY() - radius * 2; } private boolean hasBouncedOnBall(double x, double y) { for (Circle c : fineshedBalls) { if (c.contains(x, y + radius * 2)) { return true; } } return false; } private double moveDown(double y){ return y + radius; } private void drawLayout() { // sequence matters... drawBase(); drawLeftAndRightSide();