org.jfree.report.util
Class WaitingImageObserver

java.lang.Object
  org.jfree.report.util.WaitingImageObserver

All Implemented Interfaces:

java.lang.Cloneable, java.awt.image.ImageObserver, java.io.Serializable

public class WaitingImageObserver

extends java.lang.Object

implements java.awt.image.ImageObserver, java.io.Serializable, java.lang.Cloneable

This image observer blocks until the image is completely loaded. AWT defers the loading of images until they are painted on a graphic. While printing reports it is not very nice, not to know whether a image was completely loaded, so this observer forces the loading of the image until a final state (either ALLBITS, ABORT or ERROR) is reached.

Author:

Thomas Morgner

See Also:

Serialized Form

Field Summary

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

WaitingImageObserver(java.awt.Image image)
Creates a new ImageObserver for the given Image.

Method Summary

java.lang.Object	clone() Clones this WaitingImageObserver.
boolean	imageUpdate(java.awt.Image img, int infoflags, int x, int y, int width, int height) Callback function used by AWT to inform that more data is available.
boolean	isError() Returns true if there is an error condition, and false otherwise.
void	waitImageLoaded() The workerthread.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

WaitingImageObserver

public WaitingImageObserver(java.awt.Image image)

Creates a new ImageObserver for the given Image. The Oberver has to be started by an external thread.

Parameters:

image - the image to observe.

Throws:

java.lang.NullPointerException - if the given image is null.

Method Detail

imageUpdate

public boolean imageUpdate(java.awt.Image img,
                           int infoflags,
                           int x,
                           int y,
                           int width,
                           int height)

Callback function used by AWT to inform that more data is available. The observer waits until either all data is loaded or AWT signals that the image cannot be loaded.

Specified by:

imageUpdate in interface java.awt.image.ImageObserver

Parameters:

img - the image being observed.

infoflags - the bitwise inclusive OR of the following flags: WIDTH, HEIGHT, PROPERTIES, SOMEBITS, FRAMEBITS, ALLBITS, ERROR, ABORT.

x - the x coordinate.

y - the y coordinate.

width - the width.

height - the height.

Returns:

false if the infoflags indicate that the image is completely loaded; true otherwise.

waitImageLoaded

public void waitImageLoaded()

The workerthread. Simply draws the image to a BufferedImage's Graphics-Object and waits for the AWT to load the image.

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Clones this WaitingImageObserver.

Returns:

a clone.

Throws:

java.lang.CloneNotSupportedException - this should never happen.

isError

public boolean isError()

Returns true if there is an error condition, and false otherwise.

Returns:

A boolean.