结合内存缓存（如LruCache）和WeakReference

Question

您如何将内存缓存中的弱引用存储到超出缓存大小的对象？ 值得吗？ 它可以是一个新的内存缓存模式吗？ =） 或者我错过了一些已经完成它的库？

这样我们就可以通过id访问对象，即使它们是从内存缓存本身中删除的（如果我们不希望有大内存缓存）。

MemCache来源在这里：http://pastebin.com/N3iuJgNb

示例代码：

Test before1 = new Test("1");                   // Strong reference in code, weak reference in MemCache
Test before2 = new Test("2");                   // Weak reference in MemCache
Test before3 = new Test("3");                   // Strong reference in code and in MemCache
Test before4 = new Test("4");                   // Strong reference in MemCache

MemCache<Test> cache = new MemCache<Test>(2);   // At most two items are strongly referenced

cache.put(before1.id, before1);                 // Weak reference
cache.put(before2.id, before2);                 // Weak reference
cache.put(before3.id, before3);                 // Strong reference
cache.put(before4.id, before4);                 // Strong reference

before2 = null;
before4 = null;

System.gc();

try {
    Thread.sleep(5000);
} catch (InterruptedException e) {
    e.printStackTrace();
}

Test after1 = cache.get("1");                   // LruCache will return null here
Test after2 = cache.get("2");
Test after3 = cache.get("3");
Test after4 = cache.get("4");

assert after1 == before1;
assert after2 == null;
assert after3 == before3;
assert after4 != null;

System.out.println("Success!!!");