org.jfree.util
Class WaitingImageObserver

java.lang.Object
  extended by org.jfree.util.WaitingImageObserver
All Implemented Interfaces:
java.awt.image.ImageObserver, java.io.Serializable, java.lang.Cloneable

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()
          Deprecated. cloning may lock down the observer
 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.
 boolean isLoadingComplete()
          Returns true if loading is complete, 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 observer has to be started by an external thread.

Parameters:
image - the image to observe (null not permitted).
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
Deprecated. cloning may lock down the observer

Clones this WaitingImageObserver.

Overrides:
clone in class java.lang.Object
Returns:
a clone.
Throws:
java.lang.CloneNotSupportedException - this should never happen.

isLoadingComplete

public boolean isLoadingComplete()
Returns true if loading is complete, and false otherwise.

Returns:
A boolean.

isError

public boolean isError()
Returns true if there is an error condition, and false otherwise.

Returns:
A boolean.