[英]Simple Java Concurrency Issue
I have a class that extends JPanel and draws ~10 images on screen by overriding the paint method (using this method as I want to be able to manipulate the images as I draw each one). 我有一个类,它扩展了JPanel并通过覆盖paint方法在屏幕上绘制了约10张图像(使用此方法是因为我希望能够在绘制每个图像时操纵图像)。 What I want to be able to do is have an update method in the class which I pass a list of potential image updates every frame. 我想要做的是在类中有一个update方法,我每帧传递一个潜在的图像更新列表。 Here is what I have 这是我所拥有的
List<BufferedImage> imageList = Collections.synchronizedList(new ArrayList());
public void update(list<String> imagePaths) {
for (String path : imagePaths) {
synchronized (imageList) {
//Modify image list adding and removing buffered images
}
}
repaint();
}
@Override
public void paintComponent(Graphics g) {
synchronized (imageList) {
g.drawImage(img, 0, 0, this);
}
}
Currently as you can imagine it runs extremely slow due to the synchronized blocks? 正如您所能想象的那样,当前由于同步块而运行得非常慢? How can I drastically improve the performance please? 请问如何才能大大提高性能?
You're using a synchronized list, and then also synchronizing on that list when you iterate it. 您使用的是同步列表,然后又同步在名单上 ,当你重复它。 You'll probably see better performance by using something like a CopyOnWriteArrayList
, which will always provide a consistent snapshot when iterated, and remove the synchronized blocks entirely. 通过使用诸如CopyOnWriteArrayList
类的东西,您可能会看到更好的性能,该对象在迭代时将始终提供一致的快照,并完全删除同步的块。
Although, looking at your snippet, it's not clear to me which list is being iterated -- you have imageList
and imagePaths
, and I'm not sure where the actual images are retrieved from the list. 尽管查看您的代码片段,但我不清楚正在迭代哪个列表-您具有imageList
和imagePaths
,而且我不确定从列表中检索实际图像的位置。
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