java圈內圈，如何知道兩圈是否重疊

Question

這是我在java寫的一些代碼，它是一個圓圈對象類。我寫了方法，我需要兩個更多的方法，並且與第一個方法構造的是 一個包含（圓c）的方法，如果指定圓c在圓內，則返回true。第二個是一個重疊的方法（圓c），如果指定的圓c與該圓重疊，則返回true。所有我需要的是如何使這兩個方法與參數是另一個圈子對象

這是我的代碼

public class Circle 
{ 
// instance variables - replace the example below with your own 
private double radius; 
private double centerX; 
private double centerY; 

/** 
* Constructor for objects of class Circle 
*/ 
public Circle() 
{ 
    this.radius = 1; 
    this.centerX = 0; 
    this.centerY = 0; 
} 
/** 
* Constructor for objects of class Circle 
*/ 
public Circle(double radius, double centerx, double centery) 
{ 
    this.radius = radius; 
    this.centerX = centerX; 
    this.centerY = centerY; 
} 
/** 
* Constructor for objects of class Circle 
*/ 
public Circle(double pRadius) 
{ 
    radius = pRadius; 
} 
/** 
* An example of a method - replace this comment with your own 
* 
* @param y a sample parameter for a method 
* @return  the sum of x and y 
*/ 
public void setRadius(double pRadius) 
{ 
    radius = pRadius; 
} 
/** 
* getRadius method will return the radius of the cricle 
* @param none 
* @return radius of type double 
*/ 
public double getRadius() 
{ 
    return radius ; 
} 
/** 
* getcenterX method will return the x coordinates of the circle 
* @param none 
* @return centerx of type double 
*/ 
public double getCenterX() 
{ 
    return centerX ; 
} 
/** 
* getcenterY method will return the y coordinates of the circle 
* @param none 
* @return centery of type double 
*/ 
public double getCenterY() 
{ 
    return centerY ; 
} 
/** 
* 
*/ 
    public double calcPerimeter() 
{ 
    return 2*Math.PI*getRadius(); 
} 
/** 
* 
*/ 
    public double calcArea() 
{ 
    return Math.PI*Math.pow(getRadius(),2); 
} 
/** 
* 
*/ 
public double distance(double x1, double y1, double x2, double y2) 
{ 
    return (Math.sqrt(Math.pow(x1-x2,2)+ Math.pow(y1-y2,2))) ; 

} 
/** 
* 
*/ 
public boolean contains(double x, double y) 
{ 
    double dist = distance(x, y, centerX, centerY); // calculate the distance between the point(x,y) and center of the circle 
    boolean flag = false; 
    if (dist < radius) 
    { 
     flag = true; 

    } 
    else if (dist > radius) 
    { 
     flag = false ; 
    } 
    else 
    { 
     System.out.println("The point is on the circle."); 
    } 
    return flag; 
} 

} 
/** 
* 
*/ 
public String toString() 
{ 
    String outString = "The radius of the circle is: " + getRadius() + "\nThe perimeter of the circle object is; " + calcPerimeter()+ "\nThe area of the circle is: " + calcArea() ; 
    return outString; 
} 

}

Answer 1

import java.awt.geom.Point2D; 

/** 
* 
* @author MT0 
*/ 
public class Circle { 
    private Point2D.Double center; 
    private double radius; 

    public Circle(
      final double x, 
      final double y, 
      final double r 
    ){ 
     assert(r >= 0); 
     center = new Point2D.Double(x, y); 
     radius = r; 
    } 

    public Point2D.Double getCenter(){ 
     return center; 
    } 

    public double getRadius(){ 
     return radius; 
    } 

    public Double distance(final Point2D.Double point){ 
     if (point == null) 
      return null; 
     return getCenter().distance(point); 
    } 

    public boolean contains(final Point2D.Double point){ 
     if (point == null) 
      return false; 
     return distance(point) <= getRadius(); 
    } 

    public boolean overlaps(final Circle c){ 
     return distance(c.getCenter()) <= getRadius() + c.getRadius(); 
    } 

    public boolean contains(final Circle c){ 
     if (c == null) 
      return false; 
     return distance(c.getCenter()) <= Math.abs(getRadius() - c.getRadius()); 
    } 
}