Java Code Examples for com.github.benmanes.caffeine.cache.Cache#getIfPresent()

@Override
public <T> T get(String cacheName, Object key) {
    Cache cache = getCache(cacheName);
    CaffeineCacheObject data = (CaffeineCacheObject) cache.getIfPresent(key);
    if (data == null) {
        return null;
    }

    if (data.isDue()) {
        cache.invalidate(key);
        return null;
    }
    return (T) data.getValue();
}
 

@Override
public <T> T get(String cacheName, Object key, IDataLoader dataLoader) {
    Cache cache = getCache(cacheName);
    CaffeineCacheObject data = (CaffeineCacheObject) cache.getIfPresent(key);
    if (data == null || data.isDue()) {
        Object newValue = dataLoader.load();
        if (newValue != null) {
            data = new CaffeineCacheObject(newValue);
            putData(cache, key, data);
        }
        return (T) newValue;
    } else {
        return (T) data.getValue();
    }
}
 

@Override
public <T> T get(String cacheName, Object key, IDataLoader dataLoader, int liveSeconds) {
    Cache cache = getCache(cacheName);
    CaffeineCacheObject data = (CaffeineCacheObject) cache.getIfPresent(key);
    if (data == null || data.isDue()) {
        Object newValue = dataLoader.load();
        if (newValue != null) {
            data = new CaffeineCacheObject(newValue, liveSeconds);
            putData(cache, key, data);
        }
        return (T) newValue;
    } else {
        return (T) data.getValue();
    }
}
 

@Override
public Integer getTtl(String cacheName, Object key) {
    Cache cache = getCacheOnly(cacheName);
    if (cache == null) {
        return null;
    }

    CaffeineCacheObject data = (CaffeineCacheObject) cache.getIfPresent(key);
    if (data == null) {
        return null;
    }

    return data.getTtl();
}
 

@Override
public void setTtl(String cacheName, Object key, int seconds) {
    Cache cache = getCacheOnly(cacheName);
    if (cache == null) {
        return;
    }

    CaffeineCacheObject data = (CaffeineCacheObject) cache.getIfPresent(key);
    if (data == null) {
        return;
    }

    data.setLiveSeconds(seconds);
    putData(cache, key, data);
}
 

public static void test1() {
        Cache<String, double[][]> cache = Caffeine.newBuilder()
                .maximumSize(100)
                .expireAfterWrite(10, TimeUnit.MINUTES)
                .build();

        String key = "name";

        double[][] v = cache.getIfPresent(key);
        double[][] v1 = new double[0][0];

        if (null == v) {
            cache.put(key, v1);
        }

        while (true) {

            try {
                Thread.sleep(1000);

                System.err.println(cache.getIfPresent(key));
            } catch (InterruptedException e) {
                e.printStackTrace();
            }


        }
//
//        double[][] d1 = {{1, 2}, {3, 4}};
//        double[][] d2 = new double[d1.length][d1[0].length];
//        copy(d1, d2);
//
//        System.out.println(d2[1][0]);

    }
 

@Test
public void cacheExposesMetricsForHitMissAndEviction() throws Exception {
    Cache<String, String> cache = Caffeine.newBuilder().maximumSize(2).recordStats().executor(new Executor() {
        @Override
        public void execute(Runnable command) {
            // Run cleanup in same thread, to remove async behavior with evictions
            command.run();
        }
    }).build();
    CollectorRegistry registry = new CollectorRegistry();

    CacheMetricsCollector collector = new CacheMetricsCollector().register(registry);
    collector.addCache("users", cache);

    cache.getIfPresent("user1");
    cache.getIfPresent("user1");
    cache.put("user1", "First User");
    cache.getIfPresent("user1");

    // Add to cache to trigger eviction.
    cache.put("user2", "Second User");
    cache.put("user3", "Third User");
    cache.put("user4", "Fourth User");

    assertMetric(registry, "caffeine_cache_hit_total", "users", 1.0);
    assertMetric(registry, "caffeine_cache_miss_total", "users", 2.0);
    assertMetric(registry, "caffeine_cache_requests_total", "users", 3.0);
    assertMetric(registry, "caffeine_cache_eviction_total", "users", 2.0);
}
 

@Test
public void testTimeDecay() {
  Cache<Integer, String> cacheDecay = Caffeine.newBuilder()
      .executor(Runnable::run)
      .maximumSize(20)
      .build();
  for (int i = 1; i < 21; i++) {
    cacheDecay.put(i, Integer.toString(i));
  }
  Map<Integer, String> itemsDecay;

  // Now increase the freq count for 5 items
  for (int i = 0; i < 5; ++i) {
    for (int j = 0; j < 10; ++j) {
      cacheDecay.getIfPresent(i + 13);
    }
  }
  // OK, 13 - 17 should have larger counts and should stick past next few collections
  cacheDecay.put(22, "22");
  cacheDecay.put(23, "23");
  cacheDecay.put(24, "24");
  cacheDecay.put(25, "25");
  itemsDecay = cacheDecay.policy().eviction().get().hottest(10);
  // 13 - 17 should be in cache, but 11 and 18 (among others) should not. Testing that elements before and
  // after the ones with increased counts are removed, and all the increased count ones are still in the cache
  assertNull(itemsDecay.get(11));
  assertNull(itemsDecay.get(18));
  assertNotNull(itemsDecay.get(13));
  assertNotNull(itemsDecay.get(14));
  assertNotNull(itemsDecay.get(15));
  assertNotNull(itemsDecay.get(16));
  assertNotNull(itemsDecay.get(17));


  // Testing that all the elements in front of the ones with increased counts are gone
  for (int idx = 26; idx < 32; ++idx) {
    cacheDecay.put(idx, Integer.toString(idx));
  }
  //Surplus count should be at 0
  itemsDecay = cacheDecay.policy().eviction().get().hottest(10);
  assertNull(itemsDecay.get(20));
  assertNull(itemsDecay.get(24));
  assertNotNull(itemsDecay.get(13));
  assertNotNull(itemsDecay.get(14));
  assertNotNull(itemsDecay.get(15));
  assertNotNull(itemsDecay.get(16));
  assertNotNull(itemsDecay.get(17));
}
 

/**
 * Retrieves an object (of the specified class) from cache.
 * @param clazz the class of the object to retrieve from cache
 * @param key the unique identifier of the object to retrieve from cache
 * @param <T> the object type
 * @return the cached object (if found) or null if not found
 * @since 1.5.0
 */
@SuppressWarnings("unchecked")
public <T> T get(final Class clazz, final String key) {
    final Cache<String, Object> cache = typeMap.get(clazz);
    return (cache == null) ? null : (T) cache.getIfPresent(key);
}