concreteobserver.java

这个文件里面包含了java设计模式的一些例子讲解

/* Generated by Together */

package com.javapatterns.observer.imageobserver;

import java.awt.image.ImageObserver;
import java.awt.Image;
public class ConcreteObserver implements ImageObserver {
    /**
     * This method is called when information about an image which was
     * previously requested using an asynchronous interface becomes
     * available.  Asynchronous interfaces are method calls such as
     * getWidth(ImageObserver) and drawImage(img, x, y, ImageObserver)
     * which take an ImageObserver object as an argument.  Those methods
     * register the caller as interested either in information about
     * the overall image itself (in the case of getWidth(ImageObserver))
     * or about an output version of an image (in the case of the
     * drawImage(img, x, y, [w, h,] ImageObserver) call).  
     *
     * <p>This method
     * should return true if further updates are needed or false if the
     * required information has been acquired.  The image which was being
     * tracked is passed in using the img argument.  Various constants
     * are combined to form the infoflags argument which indicates what
     * information about the image is now available.  The interpretation
     * of the x, y, width, and height arguments depends on the contents
     * of the infoflags argument.
     * <p>
     * The <code>infoflags</code> argument should be the bitwise inclusive 
     * <b>OR</b> of the following flags: <code>WIDTH</code>, 
     * <code>HEIGHT</code>, <code>PROPERTIES</code>, <code>SOMEBITS</code>, 
     * <code>FRAMEBITS</code>, <code>ALLBITS</code>, <code>ERROR</code>, 
     * <code>ABORT</code>.
     *
     * @param     img   the image being observed.
     * @param     infoflags   the bitwise inclusive OR of the following 
     *               flags:  <code>WIDTH</code>, <code>HEIGHT</code>, 
     *               <code>PROPERTIES</code>, <code>SOMEBITS</code>,
     *               <code>FRAMEBITS</code>, <code>ALLBITS</code>, 
     *               <code>ERROR</code>, <code>ABORT</code>. 
     * @param     x   the <i>x</i> coordinate.
     * @param     y   the <i>y</i> coordinate.
     * @param     width    the width.
     * @param     height   the height.
     * @return    <code>false</code> if the infoflags indicate that the
     *            image is completely loaded; <code>true</code> otherwise.
     * 
     * @see #WIDTH
     * @see #HEIGHT
     * @see #PROPERTIES
     * @see #SOMEBITS
     * @see #FRAMEBITS
     * @see #ALLBITS
     * @see #ERROR
     * @see #ABORT
     * @see Image#getWidth
     * @see Image#getHeight
     * @see java.awt.Graphics#drawImage
     */
    public boolean imageUpdate(Image img, int infoflags,
			       int x, int y, int width, int height){return true; }
}