Guava Ticker 缓存过期
Guava Ticker Cache expire
Google Guava tutorial said cache expiration can be tested with Ticker
据我了解,我可以用它来强制快速过期。 我说得对吗?
但是我在下面的代码中尝试过,但是没有用,有什么建议吗?
@Test
public void expireAfterWriteTestWithTicker() throws InterruptedException {
Ticker t = new Ticker() {
@Override
public long read() {
return TimeUnit.MILLISECONDS.toNanos(5);
}
};
//Use ticker to force expire in 5 millseconds
LoadingCache<String, String> cache = CacheBuilder.newBuilder()
.expireAfterWrite(20, TimeUnit.MINUTES).ticker(t).build(loader);
cache.getUnchecked("hello");
assertEquals(1, cache.size());
assertNotNull(cache.getIfPresent("hello"));
//sleep
Thread.sleep(10);
assertNull(cache.getIfPresent("hello")); //failed
}
自己找答案
Ticker可用于跳过时间,但不能用于
class FakeTicker extends Ticker {
private final AtomicLong nanos = new AtomicLong();
/** Advances the ticker value by {@code time} in {@code timeUnit}. */
public FakeTicker advance(long time, TimeUnit timeUnit) {
nanos.addAndGet(timeUnit.toNanos(time));
return this;
}
@Override
public long read() {
long value = nanos.getAndAdd(0);
System.out.println("is called " + value);
return value;
}
}
@Test
public void expireAfterWriteTestWithTicker() throws InterruptedException {
FakeTicker t = new FakeTicker();
// Use ticker to force expire in 20 minute
LoadingCache<String, String> cache = CacheBuilder.newBuilder()
.expireAfterWrite(20, TimeUnit.MINUTES).ticker(t).build(ldr);
cache.getUnchecked("hello");
assertEquals(1, cache.size());
assertNotNull(cache.getIfPresent("hello"));
// add 21 minutes
t.advance(21, TimeUnit.MINUTES);
assertNull(cache.getIfPresent("hello"));
}
Google Guava tutorial said cache expiration can be tested with Ticker
据我了解,我可以用它来强制快速过期。 我说得对吗?
但是我在下面的代码中尝试过,但是没有用,有什么建议吗?
@Test
public void expireAfterWriteTestWithTicker() throws InterruptedException {
Ticker t = new Ticker() {
@Override
public long read() {
return TimeUnit.MILLISECONDS.toNanos(5);
}
};
//Use ticker to force expire in 5 millseconds
LoadingCache<String, String> cache = CacheBuilder.newBuilder()
.expireAfterWrite(20, TimeUnit.MINUTES).ticker(t).build(loader);
cache.getUnchecked("hello");
assertEquals(1, cache.size());
assertNotNull(cache.getIfPresent("hello"));
//sleep
Thread.sleep(10);
assertNull(cache.getIfPresent("hello")); //failed
}
自己找答案
Ticker可用于跳过时间,但不能用于
class FakeTicker extends Ticker {
private final AtomicLong nanos = new AtomicLong();
/** Advances the ticker value by {@code time} in {@code timeUnit}. */
public FakeTicker advance(long time, TimeUnit timeUnit) {
nanos.addAndGet(timeUnit.toNanos(time));
return this;
}
@Override
public long read() {
long value = nanos.getAndAdd(0);
System.out.println("is called " + value);
return value;
}
}
@Test
public void expireAfterWriteTestWithTicker() throws InterruptedException {
FakeTicker t = new FakeTicker();
// Use ticker to force expire in 20 minute
LoadingCache<String, String> cache = CacheBuilder.newBuilder()
.expireAfterWrite(20, TimeUnit.MINUTES).ticker(t).build(ldr);
cache.getUnchecked("hello");
assertEquals(1, cache.size());
assertNotNull(cache.getIfPresent("hello"));
// add 21 minutes
t.advance(21, TimeUnit.MINUTES);
assertNull(cache.getIfPresent("hello"));
}