Java ExceptionalFunction类代码示例

import com.twitter.util.ExceptionalFunction; //导入依赖的package包/类
private ExceptionalFunction<TerrapinResponse, TerrapinSingleResponse> getManyToGetOneFunction(
    final ByteBuffer key) {
  return new ExceptionalFunction<TerrapinResponse, TerrapinSingleResponse>() {
      @Override
      public TerrapinSingleResponse applyE(TerrapinResponse response) throws Throwable {
        TerrapinSingleResponse singleResponse = response.getResponseMap().get(key);
        if (singleResponse == null) {
          return new TerrapinSingleResponse();
        } else {
          if (singleResponse.isSetErrorCode()) {
            throw new TerrapinGetException().setErrorCode(singleResponse.getErrorCode());
          } else {
            return singleResponse;
          }
        }
      }
    };
}
 

import com.twitter.util.ExceptionalFunction; //导入依赖的package包/类
/**
 * Elective stream lock--readers are not required to acquire the lock before using the stream.
 */
synchronized Future<Void> lockStream() {
    if (null == lockAcquireFuture) {
        final Function0<DistributedLock> lockFunction =  new ExceptionalFunction0<DistributedLock>() {
            @Override
            public DistributedLock applyE() throws IOException {
                // Unfortunately this has a blocking call which we should not execute on the
                // ZK completion thread
                BKLogReadHandler.this.readLock = new ZKDistributedLock(
                        lockStateExecutor,
                        lockFactory,
                        readLockPath,
                        conf.getLockTimeoutMilliSeconds(),
                        statsLogger.scope("read_lock"));

                LOG.info("acquiring readlock {} at {}", getLockClientId(), readLockPath);
                return BKLogReadHandler.this.readLock;
            }
        };
        lockAcquireFuture = ensureReadLockPathExist().flatMap(new ExceptionalFunction<Void, Future<Void>>() {
            @Override
            public Future<Void> applyE(Void in) throws Throwable {
                return scheduler.apply(lockFunction).flatMap(new ExceptionalFunction<DistributedLock, Future<Void>>() {
                    @Override
                    public Future<Void> applyE(DistributedLock lock) throws IOException {
                        return acquireLockOnExecutorThread(lock);
                    }
                });
            }
        });
    }
    return lockAcquireFuture;
}
 

import com.twitter.util.ExceptionalFunction; //导入依赖的package包/类
<T> Future<T> processReaderOperation(final Function<BKLogReadHandler, Future<T>> func) {
    initializeFuturePool(false);
    return readerFuturePool.apply(new ExceptionalFunction0<BKLogReadHandler>() {
        @Override
        public BKLogReadHandler applyE() throws Throwable {
            return getReadHandlerForListener(true);
        }
    }).flatMap(new ExceptionalFunction<BKLogReadHandler, Future<T>>() {
        @Override
        public Future<T> applyE(final BKLogReadHandler readHandler) throws Throwable {
            return func.apply(readHandler);
        }
    });
}
 

import com.twitter.util.ExceptionalFunction; //导入依赖的package包/类
@Test(timeout = 60000)
public void testReaderLockCloseInAcquireCallback() throws Exception {
    final String name = runtime.getMethodName();
    DistributedLogManager dlm = createNewDLM(conf, name);
    BKAsyncLogWriter writer = (BKAsyncLogWriter)(dlm.startAsyncLogSegmentNonPartitioned());
    writer.write(DLMTestUtil.getLogRecordInstance(1L));
    writer.closeAndComplete();

    final CountDownLatch latch = new CountDownLatch(1);

    Future<AsyncLogReader> futureReader1 = dlm.getAsyncLogReaderWithLock(DLSN.InitialDLSN);
    futureReader1.flatMap(new ExceptionalFunction<AsyncLogReader, Future<Void>>() {
        @Override
        public Future<Void> applyE(AsyncLogReader reader) throws IOException {
            return reader.asyncClose().map(new AbstractFunction1<Void, Void>() {
                @Override
                public Void apply(Void result) {
                    latch.countDown();
                    return null;
                }
            });
        }
    });

    latch.await();
    dlm.close();
}
 

import com.twitter.util.ExceptionalFunction; //导入依赖的package包/类
protected void initialize() throws Exception {
  if (this.shardConfigFilePath != null) {
    String fullFilePath = getClass().getResource("/" + shardConfigFilePath).getPath();
    ConfigFileWatcher.defaultInstance().addWatch(
        fullFilePath, new ExceptionalFunction<byte[], Void>() {
      @Override
      public synchronized Void applyE(byte[] bytes) throws Exception {
        processConfigUpdate(bytes);
        return null;
      }
    });
  }

  // Initialize the future pool we will use to make blocking calls to Redis.
  // We size the future pool such that there is one thread for every available connection.
  int futurePoolSize = configuration.getInt("BACKEND_CONNECTIONS_PER_SHARD") * getShards().size();
  this.futurePool = new ExecutorServiceFuturePool(Executors.newFixedThreadPool(
      futurePoolSize,
      new ThreadFactoryBuilder().setDaemon(true).setNameFormat(
          backendName + "FuturePool-%d").build()));

  // Create a map of queueName -> aync semaphore to control dequeue concurrency.
  // We configure the map to create entries on demand since queues can be created at any time.
  final int dequeueConcurrencyPerQueue =
      configuration.getInt("BACKEND_DEQUEUE_CONCURRENCY_PER_QUEUE_PER_SHARD") * getShards()
          .size();
  // We set maxWaiters on the async semaphore to the max concurrency on the server as an
  // additional safety measure.
  final int maxWaiters = configuration.getInt("MAX_CONCURRENT_REQUESTS");
  this.dequeueSemaphoreMap = CacheBuilder.newBuilder().build(
      new CacheLoader<String, AsyncSemaphore>() {
        @Override
        public AsyncSemaphore load(String queueName) throws Exception {
          AsyncSemaphore asyncSemaphore =
              new AsyncSemaphore(dequeueConcurrencyPerQueue, maxWaiters);
          Stats.setGauge("dequeue-semaphore-waiters-" + queueName, asyncSemaphore.numWaiters());
          return asyncSemaphore;
        }
      });
}
 

import com.twitter.util.ExceptionalFunction; //导入依赖的package包/类
public void initialize() throws Exception {
  // Check if use of serverset is enabled, and if so, register a change monitor so we
  // can find out how many PinLater servers are active. We use this to compute the
  // per-server rate limit.
  if (pinlaterServerSetEnabled) {
    MorePreconditions.checkNotBlank(pinlaterServerSetPath);
    LOG.info("Monitoring pinlater serverset: {}", pinlaterServerSetPath);
    String fullServerSetPath = getClass().getResource("/" + pinlaterServerSetPath).getPath();
    ServerSet serverSet = new ConfigFileServerSet(fullServerSetPath);
    serverSet.monitor(new DynamicHostSet.HostChangeMonitor<ServiceInstance>() {
      @Override
      public void onChange(ImmutableSet<ServiceInstance> hostSet) {
        int oldSize = numPinLaterServers.get();
        int newSize = hostSet.size();
        if (newSize == 0) {
          LOG.error("PinLater serverset is empty, ignoring and keeping old size: {}", oldSize);
          return;
        }
        if (oldSize == newSize) {
          LOG.info("PinLater serverset update, size unchanged: {}", oldSize);
          return;
        }

        LOG.info("PinLater serverset update, old size: {}, new size: {}", oldSize, newSize);
        numPinLaterServers.set(newSize);
        rebuild();
      }
    });
  } else {
    LOG.info("PinLater server set is disabled; rate limits will be applied per server.");
  }

  if (queueConfigFilePath == null || queueConfigFilePath.isEmpty()) {
    LOG.info("Queue config zookeeper path not specified, using defaults.");
    return;
  }

  LOG.info("Registering watch on queue config: {}", queueConfigFilePath);
  String fullQueueConfigFilePath = getClass().getResource("/" + queueConfigFilePath).getPath();
  ConfigFileWatcher.defaultInstance().addWatch(
      fullQueueConfigFilePath, new ExceptionalFunction<byte[], Void>() {
        @Override
        public Void applyE(byte[] bytes) throws Exception {
          QueueConfigSchema queueConfigSchema = QueueConfigSchema.load(bytes);
          LOG.info("Queue config update, new value: {}", queueConfigSchema);
          queueConfigSchemaRef.set(queueConfigSchema);
          rebuild();
          return null;
        }
      });
}
 

import com.twitter.util.ExceptionalFunction; //导入依赖的package包/类
@Override
public Future<TerrapinSingleResponse> get(final TerrapinGetRequest request) {
  final long startTimeMillis = System.currentTimeMillis();
  if (request.getClusterList().isEmpty()) {
    return Future.exception(new TerrapinGetException("Cluster list is empty", TerrapinGetErrorCode.INVALID_REQUEST));
  }
  ReplicatedTerrapinClient terrapinClient = getReplicatedTerrapinClient(request.getClusterList());
  if (terrapinClient == null) {
    return Future.exception(new TerrapinGetException(
        "Clusters [" + Joiner.on(", ").join(request.getClusterList()) + "] not found.",
        TerrapinGetErrorCode.CLUSTER_NOT_FOUND));
  }
  RequestOptions options;
  if (request.isSetOptions()) {
    options = request.getOptions();
  } else {
    options = new RequestOptions();
  }
  try {
    return terrapinClient.getMany(request.getFileSet(),
        Sets.newHashSet(ByteBuffer.wrap(request.getKey())), options).map(
            new ExceptionalFunction<TerrapinResponse, TerrapinSingleResponse>() {
              @Override
              public TerrapinSingleResponse applyE(TerrapinResponse response)
                  throws TerrapinGetException {
                ByteBuffer keyBuf = ByteBuffer.wrap(request.getKey());
                if (response.getResponseMap().containsKey(keyBuf)) {
                  TerrapinSingleResponse returnResponse = response.getResponseMap().get(keyBuf);
                  if (returnResponse.isSetErrorCode()) {
                    throw new TerrapinGetException("Read failed.", returnResponse.getErrorCode());
                  } else {
                    Stats.addMetric(request.getFileSet() + "-value-size", returnResponse.getValue().length);
                    Stats.addMetric("value-size", returnResponse.getValue().length);
                    return returnResponse;
                  }
                } else {
                  return new TerrapinSingleResponse();
                }
              }
            }).rescue(new Function<Throwable, Future<TerrapinSingleResponse>>() {
              @Override
              public Future<TerrapinSingleResponse> apply(Throwable t) {
                return getExceptionFuture(t);
              }
            }).ensure(new Function0<BoxedUnit>() {
              @Override
              public BoxedUnit apply() {
                int timeMillis = (int)(System.currentTimeMillis() - startTimeMillis);
                Stats.addMetric(request.getFileSet() + "-lookup-latency-ms", timeMillis);
                Stats.addMetric("lookup-latency-ms", timeMillis);
                return BoxedUnit.UNIT;
              }
          });
  } catch (Exception e) {
    return getExceptionFuture(e);
  }
}