Java LoadingCache.put方法代码示例

import com.google.common.cache.LoadingCache; //导入方法依赖的package包/类
/**
 * @param args
 * @throws ExecutionException 
 * @throws InterruptedException 
 */
public static void main(String[] args) throws ExecutionException, InterruptedException {
	LoadingCache<String, String> cache = null;
	cache = CacheBuilder.newBuilder()
			// 设置并发级别为200，并发级别是指可以同时写缓存的线程数
			.concurrencyLevel(200)
			// 设置写缓存后1分钟过期
			.expireAfterWrite(1, TimeUnit.SECONDS).initialCapacity(10).maximumSize(100)
			// 设置要统计缓存的命中率
			.recordStats()
			// 设置缓存的移除通知
			.removalListener(new RemovalListener<String, String>() {
				@Override
				public void onRemoval(RemovalNotification<String, String> notification) {
					System.out.println(notification.getKey() + " was removed, cause by " + notification.getCause());
				}
			}).build(new CacheLoader<String, String>() {
				// build方法中可以指定CacheLoader，在缓存不存在时通过CacheLoader的实现自动加载缓存
				@Override
				public String load(String appIdSecret) throws Exception {
					return "";
				}
			});
	
	cache.put("key1", "value1");
	System.out.println(cache.get("key1"));
	Thread.sleep(2000);
	System.out.println(cache.get("key1"));
}
 

import com.google.common.cache.LoadingCache; //导入方法依赖的package包/类
@Override
public synchronized void put(@NonNull String key, @NonNull V value)
{
	checkNotNull(key);
	checkNotNull(value);

	LoadingCache<String, Optional<ExpiringValue<V>>> c = cache.getUnchecked(CurrentInstitution.get());

	// Do nothing if the value hasn't changed
	Optional<ExpiringValue<V>> opExVal = c.getIfPresent(key);
	if( opExVal != null && opExVal.isPresent() )
	{
		V oldValue = opExVal.get().getValue();
		if( oldValue != null && oldValue.equals(value) )
		{
			return;
		}
	}

	// Update the DB state if it's clustered
	if( zookeeperService.isCluster() )
	{
		dao.put(cacheId, key, new Date(System.currentTimeMillis() + ttlUnit.toMillis(ttl)),
			PluginAwareObjectOutputStream.toBytes(value));
	}

	// Invalidate other servers caches
	invalidateOthers(key);

	// Update our local cache
	c.put(key, Optional.of(ExpiringValue.expireAfter(value, ttl, ttlUnit)));
}
 

import com.google.common.cache.LoadingCache; //导入方法依赖的package包/类
@Test
public void test_001() throws ExecutionException {
    LoadingCache<String,Object> failedCache = CacheBuilder.newBuilder().
            softValues().maximumSize(10000)
            .build(new CacheLoader<String, Object>() {

                @Override
                public Object load(String s) throws Exception {
                    return new AtomicInteger(0);
                }
            });

    failedCache.put("00",((AtomicInteger)failedCache.get("00")).incrementAndGet());
    System.out.println(failedCache.get("00"));
}
 

import com.google.common.cache.LoadingCache; //导入方法依赖的package包/类
@SuppressWarnings("unchecked")
@Override
public void getMetadata(LoadingCache<String, Map<String, String>> metadata, File f)
{
	// You don't even need to touch power lines to die. DON'T DIE!
	if( Check.isEmpty(exifToolPath) || !Files.exists(Paths.get(exifToolPath)) || !f.exists() )
	{
		return;
	}

	List<String> commandOpts = Lists.newArrayList();
	commandOpts.add(exifToolPath);
	commandOpts.add("-g"); // Group (EXIF, XMP etc)
	commandOpts.add("-j"); // JSON output
	commandOpts.add("-q"); // Quiet processing
	commandOpts.add("-sort"); // Alphabetical sort
	commandOpts.add("-struct"); // Expand structs (ewww)
	commandOpts.add("-u"); // Unsupported tags

	// Remove unsafe tags e.g Directory/Permissions etc
	for( String tag : removeTags )
	{
		commandOpts.add("-x");
		commandOpts.add(tag);
	}

	// File to process
	commandOpts.add(f.getAbsolutePath());

	ObjectMapper om = new ObjectMapper();
	List<Map<String, Object>> outputList = Lists.newArrayList();

	try
	{
		ExecResult exec = ExecUtils.exec(commandOpts);
		String stdout = exec.getStdout();
		Map<String, Object> jsonMap = Maps.newHashMap();
		flatten(om.readTree(stdout).get(0), jsonMap, false);
		outputList.add(jsonMap);
	}
	catch( IOException e )
	{
		throw Throwables.propagate(e);
	}

	// This is a bit dodgical... but seems to be a necessary evil
	for( final Entry<String, Object> objectMap : outputList.get(0).entrySet() )
	{
		if( objectMap.getValue() instanceof Map )
		{
			metadata.put(objectMap.getKey(),
				Maps.transformValues(((Map<String, Object>) objectMap.getValue()), Functions.toStringFunction()));
		}
	}
}