Effect: Animated Image Sequences - JavaFX Special Effects - page 145

Figure 7-7. Path in NetBeans
To load the Image , the function getImage first checks a local Map named imageMap to see if the image
was loaded in the past. If the Image was loaded, it is simply returned. If the Image was not loaded, a new
Image is created based on the values passed into the function and stored in the Map imageMap before it is
returned.
The pattern of loading items only once as seen in the function getImage is used again in the function
getImageSequence . It first checks to see if an appropriate ImageSequence was created and hence stored in
the Map sequenceMap . If the ImageSequence was already loaded, it is then returned. If it was not previously
created, a new ImageSequence map is created, stored, and returned.
When this pattern is implemented in Java, care must be taken to make sure that two threads don't
ask for the same resource in such a way as to cause the image to be loaded twice. With JavaFX this is not
strictly required, as the JavaFX event thread is effectively single threaded—though it should be noted
that someone could write a Java method that could access the MediaLoader in a multi-threaded way. But
as long as you only call these methods from JavaFX, you will be OK.