Java tutorial
/* * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.awt.geom; import java.io.Serializable; /** * The {@code Point2D} class defines a point representing a location * in {@code (x,y)} coordinate space. * <p> * This class is only the abstract superclass for all objects that * store a 2D coordinate. * The actual storage representation of the coordinates is left to * the subclass. * * @author Jim Graham * @since 1.2 */ public abstract class Point2D implements Cloneable { /** * The {@code Float} class defines a point specified in float * precision. * @since 1.2 */ public static class Float extends Point2D implements Serializable { /** * The X coordinate of this {@code Point2D}. * @since 1.2 * @serial */ public float x; /** * The Y coordinate of this {@code Point2D}. * @since 1.2 * @serial */ public float y; /** * Constructs and initializes a {@code Point2D} with * coordinates (0, 0). * @since 1.2 */ public Float() { } /** * Constructs and initializes a {@code Point2D} with * the specified coordinates. * * @param x the X coordinate of the newly * constructed {@code Point2D} * @param y the Y coordinate of the newly * constructed {@code Point2D} * @since 1.2 */ public Float(float x, float y) { this.x = x; this.y = y; } /** * {@inheritDoc} * @since 1.2 */ public double getX() { return (double) x; } /** * {@inheritDoc} * @since 1.2 */ public double getY() { return (double) y; } /** * {@inheritDoc} * @since 1.2 */ public void setLocation(double x, double y) { this.x = (float) x; this.y = (float) y; } /** * Sets the location of this {@code Point2D} to the * specified {@code float} coordinates. * * @param x the new X coordinate of this {@code Point2D} * @param y the new Y coordinate of this {@code Point2D} * @since 1.2 */ public void setLocation(float x, float y) { this.x = x; this.y = y; } /** * Returns a {@code String} that represents the value * of this {@code Point2D}. * @return a string representation of this {@code Point2D}. * @since 1.2 */ public String toString() { return "Point2D.Float[" + x + ", " + y + "]"; } /* * JDK 1.6 serialVersionUID */ private static final long serialVersionUID = -2870572449815403710L; } /** * The {@code Double} class defines a point specified in * {@code double} precision. * @since 1.2 */ public static class Double extends Point2D implements Serializable { /** * The X coordinate of this {@code Point2D}. * @since 1.2 * @serial */ public double x; /** * The Y coordinate of this {@code Point2D}. * @since 1.2 * @serial */ public double y; /** * Constructs and initializes a {@code Point2D} with * coordinates (0, 0). * @since 1.2 */ public Double() { } /** * Constructs and initializes a {@code Point2D} with the * specified coordinates. * * @param x the X coordinate of the newly * constructed {@code Point2D} * @param y the Y coordinate of the newly * constructed {@code Point2D} * @since 1.2 */ public Double(double x, double y) { this.x = x; this.y = y; } /** * {@inheritDoc} * @since 1.2 */ public double getX() { return x; } /** * {@inheritDoc} * @since 1.2 */ public double getY() { return y; } /** * {@inheritDoc} * @since 1.2 */ public void setLocation(double x, double y) { this.x = x; this.y = y; } /** * Returns a {@code String} that represents the value * of this {@code Point2D}. * @return a string representation of this {@code Point2D}. * @since 1.2 */ public String toString() { return "Point2D.Double[" + x + ", " + y + "]"; } /* * JDK 1.6 serialVersionUID */ private static final long serialVersionUID = 6150783262733311327L; } /** * This is an abstract class that cannot be instantiated directly. * Type-specific implementation subclasses are available for * instantiation and provide a number of formats for storing * the information necessary to satisfy the various accessor * methods below. * * @see java.awt.geom.Point2D.Float * @see java.awt.geom.Point2D.Double * @see java.awt.Point * @since 1.2 */ protected Point2D() { } /** * Returns the X coordinate of this {@code Point2D} in * {@code double} precision. * @return the X coordinate of this {@code Point2D}. * @since 1.2 */ public abstract double getX(); /** * Returns the Y coordinate of this {@code Point2D} in * {@code double} precision. * @return the Y coordinate of this {@code Point2D}. * @since 1.2 */ public abstract double getY(); /** * Sets the location of this {@code Point2D} to the * specified {@code double} coordinates. * * @param x the new X coordinate of this {@code Point2D} * @param y the new Y coordinate of this {@code Point2D} * @since 1.2 */ public abstract void setLocation(double x, double y); /** * Sets the location of this {@code Point2D} to the same * coordinates as the specified {@code Point2D} object. * @param p the specified {@code Point2D} to which to set * this {@code Point2D} * @since 1.2 */ public void setLocation(Point2D p) { setLocation(p.getX(), p.getY()); } /** * Returns the square of the distance between two points. * * @param x1 the X coordinate of the first specified point * @param y1 the Y coordinate of the first specified point * @param x2 the X coordinate of the second specified point * @param y2 the Y coordinate of the second specified point * @return the square of the distance between the two * sets of specified coordinates. * @since 1.2 */ public static double distanceSq(double x1, double y1, double x2, double y2) { x1 -= x2; y1 -= y2; return (x1 * x1 + y1 * y1); } /** * Returns the distance between two points. * * @param x1 the X coordinate of the first specified point * @param y1 the Y coordinate of the first specified point * @param x2 the X coordinate of the second specified point * @param y2 the Y coordinate of the second specified point * @return the distance between the two sets of specified * coordinates. * @since 1.2 */ public static double distance(double x1, double y1, double x2, double y2) { x1 -= x2; y1 -= y2; return Math.sqrt(x1 * x1 + y1 * y1); } /** * Returns the square of the distance from this * {@code Point2D} to a specified point. * * @param px the X coordinate of the specified point to be measured * against this {@code Point2D} * @param py the Y coordinate of the specified point to be measured * against this {@code Point2D} * @return the square of the distance between this * {@code Point2D} and the specified point. * @since 1.2 */ public double distanceSq(double px, double py) { px -= getX(); py -= getY(); return (px * px + py * py); } /** * Returns the square of the distance from this * {@code Point2D} to a specified {@code Point2D}. * * @param pt the specified point to be measured * against this {@code Point2D} * @return the square of the distance between this * {@code Point2D} to a specified {@code Point2D}. * @since 1.2 */ public double distanceSq(Point2D pt) { double px = pt.getX() - this.getX(); double py = pt.getY() - this.getY(); return (px * px + py * py); } /** * Returns the distance from this {@code Point2D} to * a specified point. * * @param px the X coordinate of the specified point to be measured * against this {@code Point2D} * @param py the Y coordinate of the specified point to be measured * against this {@code Point2D} * @return the distance between this {@code Point2D} * and a specified point. * @since 1.2 */ public double distance(double px, double py) { px -= getX(); py -= getY(); return Math.sqrt(px * px + py * py); } /** * Returns the distance from this {@code Point2D} to a * specified {@code Point2D}. * * @param pt the specified point to be measured * against this {@code Point2D} * @return the distance between this {@code Point2D} and * the specified {@code Point2D}. * @since 1.2 */ public double distance(Point2D pt) { double px = pt.getX() - this.getX(); double py = pt.getY() - this.getY(); return Math.sqrt(px * px + py * py); } /** * Creates a new object of the same class and with the * same contents as this object. * @return a clone of this instance. * @exception OutOfMemoryError if there is not enough memory. * @see java.lang.Cloneable * @since 1.2 */ public Object clone() { try { return super.clone(); } catch (CloneNotSupportedException e) { // this shouldn't happen, since we are Cloneable throw new InternalError(e); } } /** * Returns the hashcode for this {@code Point2D}. * @return a hash code for this {@code Point2D}. */ public int hashCode() { long bits = java.lang.Double.doubleToLongBits(getX()); bits ^= java.lang.Double.doubleToLongBits(getY()) * 31; return (((int) bits) ^ ((int) (bits >> 32))); } /** * Determines whether or not two points are equal. Two instances of * {@code Point2D} are equal if the values of their * {@code x} and {@code y} member fields, representing * their position in the coordinate space, are the same. * @param obj an object to be compared with this {@code Point2D} * @return {@code true} if the object to be compared is * an instance of {@code Point2D} and has * the same values; {@code false} otherwise. * @since 1.2 */ public boolean equals(Object obj) { if (obj instanceof Point2D) { Point2D p2d = (Point2D) obj; return (getX() == p2d.getX()) && (getY() == p2d.getY()); } return super.equals(obj); } }