java - Implementing a Write-Back Cache in Java

Question

I trying to implement a write-back cache. I'm trying to use soft referenes, but I'm having troubles performing the post-mortum write-back because the reference is cleared before it's added to the gcQueue and thus I don't have access to the referent object.

Solutions?

Answer 1

你可以试试Guava 的 Mapmaker。

例子：

final ConcurrentMap<Long, Integer> cache = new MapMaker()
        .softValues().expiration(20,TimeUnit.MINUTES)
        .makeComputingMap(new Function<Long, Integer>() {
              @Override
            public Integer apply(Long arg0) {
                return null;
            }
            });

关于 MapMaker 的问题：

• 使用 Google 集合 MapMaker ？
• 使用 MapMaker 创建缓存

替代选项：

使用 Supplier 类的memoizeWithExpiration，它也是 guava 库的一部分。