point.java

Java与模式 源代码

package com.javapatterns.immutable.point;

public class Point implements java.io.Serializable
{
    private int x;
    private int y;

    public Point(int x, int y)
    {
        this.x = x;
        this.y = y;
    }

    public Point()
    {
        this(0, 0);
    }

    public Point(Point p)
    {
        this(p.x, p.y);
    }

    /** Returns the X coordinate of the point in double precision. */
    public double getX()
    {
        return x;
    }

    /** Returns the Y coordinate of the point in double precision. */
    public double getY()
    {
        return y;
    }

    /**
     * Returns the location of this point. This method is included for completeness, to parallel the
     * <code>getLocation</code> method of <code>Component</code>.
     */
    public Point getLocation()
    {
        return new Point(x, y);
    }

    /**
     * Sets the location of the point to the specificed location. This method is included for completeness, to parallel the
     * <code>setLocation</code> method of <code>Component</code>.
     */
    public Point setLocation(Point p)
    {
        return new Point(p.x, p.y);
    }

    /**
     * Changes the point to have the specificed location. <p> This method is included for completeness, to parallel the
     * <code>setLocation</code> method of <code>Component</code>.
     * Its behavior is identical with <code>move(int,&nbsp;int)</code>.
     */
    public Point setLocation(int x, int y)
    {
        return new Point(x, y);
    }

    /** Sets the location of this point to the specified float coordinates. */
    public Point setLocation(double x, double y)
    {
        return new Point((int)Math.round(x), (int)Math.round(y));
    }

    /**
     * Moves this point to the specificed location in the (<i>x</i>,&nbsp;<i>y</i>) coordinate plane. This method
     * is identical with <code>setLocation(int,&nbsp;int)</code>.
     */
    public Point move(int x, int y)
    {
        return new Point(x, y);
    }

    /**
     * Translates this point, at location (<i>x</i>,&nbsp;<i>y</i>),
     * by <code>dx</code> along the <i>x</i> axis and <code>dy</code>
     * along the <i>y</i> axis so that it now represents the point (<code>x</code>&nbsp;<code>+</code>&nbsp;<code>dx</code>,
     * <code>y</code>&nbsp;<code>+</code>&nbsp;<code>dy</code>).
     */
    public Point translate(int x, int y)
    {
        return new Point(this.x + x, this.y + y);
    }

    /**
     * Determines whether an instance of <code>Point2D</code> is equal
     * to this point.  Two instances of <code>Point2D</code> are equal if
     * the values of their <code>x</code> and <code>y</code> member
     * fields, representing their position in the coordinate space, are the same.
     */
    public boolean equals(Object obj)
    {
        if (obj instanceof Point)
        {
            Point pt = (Point)obj;
            return (x == pt.x) && (y == pt.y);
        }
        return super.equals(obj);
    }

    /**
     * Returns a string representation of this point and its location
     * in the (<i>x</i>,&nbsp;<i>y</i>) coordinate space. This method is
     * intended to be used only for debugging purposes, and the content
     * and format of the returned string may vary between implementations.
     * The returned string may be empty but may not be <code>null</code>.
     */
    public String toString()
    {
        return getClass().getName() + "[x=" + x + ",y=" + y + "]";
    }
}