本文整理了Java中org.apache.helix.manager.zk.ZkClient.exists()方法的一些代码示例，展示了ZkClient.exists()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。ZkClient.exists()方法的具体详情如下：
包路径：org.apache.helix.manager.zk.ZkClient
类名称：ZkClient
方法名：exists

ZkClient.exists介绍

暂无

代码示例

代码示例来源：origin: apache/incubator-pinot

@Override
 public boolean execute()
   throws Exception {
  LOGGER.info("Connecting to Zookeeper at address: {}", _zkAddress);
  ZkClient zkClient = new ZkClient(_zkAddress, 5000);
  String helixClusterName = "/" + _clusterName;

  LOGGER.info("Executing command: " + toString());
  if (!zkClient.exists(helixClusterName)) {
   LOGGER.error("Cluster {} does not exist.", _clusterName);
   return false;
  }

  zkClient.deleteRecursive(helixClusterName);
  return true;
 }
}

代码示例来源：origin: apache/incubator-pinot

protected void startController(ControllerConf config) {
 Assert.assertNotNull(config);
 Assert.assertNull(_controllerStarter);
 _controllerPort = Integer.valueOf(config.getControllerPort());
 _controllerBaseApiUrl = "http://localhost:" + _controllerPort;
 _controllerRequestURLBuilder = ControllerRequestURLBuilder.baseUrl(_controllerBaseApiUrl);
 _controllerDataDir = config.getDataDir();
 String helixClusterName = getHelixClusterName();
 config.setHelixClusterName(helixClusterName);
 String zkStr = config.getZkStr();
 _zkClient = new ZkClient(zkStr);
 if (_zkClient.exists("/" + helixClusterName)) {
  _zkClient.deleteRecursive("/" + helixClusterName);
 }
 startControllerStarter(config);
 _helixManager = _helixResourceManager.getHelixZkManager();
 _helixAdmin = _helixResourceManager.getHelixAdmin();
 _propertyStore = _helixResourceManager.getPropertyStore();
}

代码示例来源：origin: org.apache.helix/helix-core

/**
 * sync exists
 */
@Override
public boolean exists(String path, int options) {
 return _zkClient.exists(path);
}

代码示例来源：origin: apache/helix

@Override
 public void run() {
  zkClient.exists(TEST_ROOT);
 }
});

代码示例来源：origin: org.apache.helix/helix-core

public static void updateIfExists(ZkClient client, String path, final ZNRecord record,
  boolean mergeOnUpdate) {
 if (client.exists(path)) {
  DataUpdater<Object> updater = new DataUpdater<Object>() {
   @Override
   public Object update(Object currentData) {
    return record;
   }
  };
  client.updateDataSerialized(path, updater);
 }
}

代码示例来源：origin: org.apache.helix/helix-core

public static void subtract(ZkClient client, String path, final ZNRecord recordTosubtract) {
  int retryCount = 0;
  while (retryCount < RETRYLIMIT) {
   try {
    if (client.exists(path)) {
     DataUpdater<ZNRecord> updater = new DataUpdater<ZNRecord>() {
      @Override
      public ZNRecord update(ZNRecord currentData) {
       currentData.subtract(recordTosubtract);
       return currentData;
      }
     };
     client.updateDataSerialized(path, updater);
     break;
    }
   } catch (Exception e) {
    retryCount = retryCount + 1;
    logger.warn("Exception trying to createOrReplace " + path + ". Will retry.", e);
   }
  }

 }
}

代码示例来源：origin: org.apache.helix/helix-core

String root = "/" + clusterName;
if (_zkClient.exists(root)) {
 if (recreateIfExists) {
  logger.warn("Root directory exists.Cleaning the root directory:" + root);
} catch (Exception e) {
 if (_zkClient.exists(root)) {
  return true;

代码示例来源：origin: org.apache.helix/helix-core

public static void createOrReplace(ZkClient client, String path, final ZNRecord record,
  final boolean persistent) {
 int retryCount = 0;
 while (retryCount < RETRYLIMIT) {
  try {
   if (client.exists(path)) {
    DataUpdater<Object> updater = new DataUpdater<Object>() {
     @Override
     public Object update(Object currentData) {
      return record;
     }
    };
    client.updateDataSerialized(path, updater);
   } else {
    CreateMode mode = (persistent) ? CreateMode.PERSISTENT : CreateMode.EPHEMERAL;
    client.create(path, record, mode);
   }
   break;
  } catch (Exception e) {
   retryCount = retryCount + 1;
   logger.warn("Exception trying to createOrReplace " + path + " Exception:" + e.getMessage()
     + ". Will retry.");
  }
 }
}

代码示例来源：origin: org.apache.helix/helix-core

public static void createOrUpdate(ZkClient client, String path, final ZNRecord record,
  final boolean persistent, final boolean mergeOnUpdate) {
 int retryCount = 0;
 while (retryCount < RETRYLIMIT) {
  try {
   if (client.exists(path)) {
    DataUpdater<ZNRecord> updater = new DataUpdater<ZNRecord>() {
     @Override public ZNRecord update(ZNRecord currentData) {
      if (currentData != null && mergeOnUpdate) {
       currentData.update(record);
       return currentData;
      }
      return record;
     }
    };
    client.updateDataSerialized(path, updater);
   } else {
    CreateMode mode = (persistent) ? CreateMode.PERSISTENT : CreateMode.EPHEMERAL;
    client.create(path, record, mode);
   }
   break;
  } catch (Exception e) {
   retryCount = retryCount + 1;
   logger.warn("Exception trying to update " + path + " Exception:" + e.getMessage()
     + ". Will retry.");
  }
 }
}

代码示例来源：origin: org.apache.helix/helix-core

public static boolean isInstanceSetup(ZkClient zkclient, String clusterName, String instanceName,
  InstanceType type) {
 if (type == InstanceType.PARTICIPANT || type == InstanceType.CONTROLLER_PARTICIPANT) {
  ArrayList<String> requiredPaths = new ArrayList<>();
  requiredPaths.add(PropertyPathBuilder.instanceConfig(clusterName, instanceName));
  requiredPaths.add(PropertyPathBuilder.instanceMessage(clusterName, instanceName));
  requiredPaths.add(PropertyPathBuilder.instanceCurrentState(clusterName, instanceName));
  requiredPaths.add(PropertyPathBuilder.instanceStatusUpdate(clusterName, instanceName));
  requiredPaths.add(PropertyPathBuilder.instanceError(clusterName, instanceName));
  boolean isValid = true;
  for (String path : requiredPaths) {
   if (!zkclient.exists(path)) {
    isValid = false;
    logger.error("Invalid instance setup, missing znode path: {}", path);
   }
  }
  if (isValid) {
   // Create the instance history node if it does not exist.
   // This is for back-compatibility.
   String historyPath = PropertyPathBuilder.instanceHistory(clusterName, instanceName);
   if (!zkclient.exists(historyPath)) {
    zkclient.createPersistent(historyPath, true);
   }
  }
  return isValid;
 }
 return true;
}

代码示例来源：origin: apache/helix

public static String getInstancePropertyNameListAsString(ZkClient zkClient, String clusterName,
  String instanceName, PropertyType instanceProperty, String key, MediaType mediaType)
  throws JsonGenerationException, JsonMappingException, IOException {
 String path = PropertyPathBuilder.instanceProperty(clusterName, instanceName, instanceProperty, key);
 if (zkClient.exists(path)) {
  List<String> recordNames = zkClient.getChildren(path);
  return ObjectToJson(recordNames);
 }
 return ObjectToJson(new ArrayList<String>());
}

代码示例来源：origin: org.apache.helix/helix-core

@Override
public void addResource(String clusterName, String resourceName,
  IdealState idealstate) {
 logger.info("Add resource {} in cluster {}.", resourceName, clusterName);
 String stateModelRef = idealstate.getStateModelDefRef();
 String stateModelDefPath = PropertyPathBuilder.stateModelDef(clusterName, stateModelRef);
 if (!_zkClient.exists(stateModelDefPath)) {
  throw new HelixException(
    "State model " + stateModelRef + " not found in the cluster STATEMODELDEFS path");
 }
 String idealStatePath = PropertyPathBuilder.idealState(clusterName);
 String resourceIdealStatePath = idealStatePath + "/" + resourceName;
 if (_zkClient.exists(resourceIdealStatePath)) {
  throw new HelixException("Skip the operation. Resource ideal state directory already exists:"
    + resourceIdealStatePath);
 }
 ZKUtil.createChildren(_zkClient, idealStatePath, idealstate.getRecord());
}

代码示例来源：origin: org.apache.helix/helix-core

@Override
public void dropInstance(String clusterName, InstanceConfig instanceConfig) {
 logger.info("Drop instance {} from cluster {}.", instanceConfig.getInstanceName(), clusterName);
 String instanceName = instanceConfig.getInstanceName();
 String instanceConfigPath = PropertyPathBuilder.instanceConfig(clusterName, instanceName);
 if (!_zkClient.exists(instanceConfigPath)) {
  throw new HelixException(
    "Node " + instanceName + " does not exist in config for cluster " + clusterName);
 }
 String instancePath = PropertyPathBuilder.instance(clusterName, instanceName);
 if (!_zkClient.exists(instancePath)) {
  throw new HelixException(
    "Node " + instanceName + " does not exist in instances for cluster " + clusterName);
 }
 String liveInstancePath = PropertyPathBuilder.liveInstance(clusterName, instanceName);
 if (_zkClient.exists(liveInstancePath)) {
  throw new HelixException(
    "Node " + instanceName + " is still alive for cluster " + clusterName + ", can't drop.");
 }
 // delete config path
 String instanceConfigsPath = PropertyPathBuilder.instanceConfig(clusterName);
 ZKUtil.dropChildren(_zkClient, instanceConfigsPath, instanceConfig.getRecord());
 // delete instance path
 _zkClient.deleteRecursively(instancePath);
}

代码示例来源：origin: org.apache.helix/helix-core

@Override
public void addStateModelDef(String clusterName, String stateModelDef,
  StateModelDefinition stateModel, boolean recreateIfExists) {
 logger
   .info("Add StateModelDef {} in cluster {} with StateModel {}.", stateModelDef, clusterName,
     stateModel == null ? "NULL" : stateModel.toString());
 if (!ZKUtil.isClusterSetup(clusterName, _zkClient)) {
  throw new HelixException("cluster " + clusterName + " is not setup yet");
 }
 String stateModelDefPath = PropertyPathBuilder.stateModelDef(clusterName);
 String stateModelPath = stateModelDefPath + "/" + stateModelDef;
 if (_zkClient.exists(stateModelPath)) {
  if (recreateIfExists) {
   logger.info(
     "Operation.State Model directory exists:" + stateModelPath + ", remove and recreate.");
   _zkClient.deleteRecursively(stateModelPath);
  } else {
   logger.info("Skip the operation. State Model directory exists:" + stateModelPath);
   return;
  }
 }
 HelixDataAccessor accessor =
   new ZKHelixDataAccessor(clusterName, new ZkBaseDataAccessor<ZNRecord>(_zkClient));
 Builder keyBuilder = accessor.keyBuilder();
 accessor.setProperty(keyBuilder.stateModelDef(stateModelDef), stateModel);
}

代码示例来源：origin: org.apache.helix/helix-core

@Override
public InstanceConfig getInstanceConfig(String clusterName, String instanceName) {
 logger.info("Get instance config for instance {} from cluster {}.", instanceName, clusterName);
 String instanceConfigPath = PropertyPathBuilder.instanceConfig(clusterName, instanceName);
 if (!_zkClient.exists(instanceConfigPath)) {
  throw new HelixException(
    "instance" + instanceName + " does not exist in cluster " + clusterName);
 }
 HelixDataAccessor accessor =
   new ZKHelixDataAccessor(clusterName, new ZkBaseDataAccessor<ZNRecord>(_zkClient));
 Builder keyBuilder = accessor.keyBuilder();
 return accessor.getProperty(keyBuilder.instanceConfig(instanceName));
}

代码示例来源：origin: org.apache.helix/helix-core

while (retryCount < RETRYLIMIT) {
 try {
  if (client.exists(path)) {
   DataUpdater<ZNRecord> updater = new DataUpdater<ZNRecord>() {
    @Override

代码示例来源：origin: org.apache.helix/helix-core

public static void asyncCreateOrMerge(ZkClient client, String path, final ZNRecord record,
  final boolean persistent, final boolean mergeOnUpdate) {
 try {
  if (client.exists(path)) {
   if (mergeOnUpdate) {
    ZNRecord curRecord = client.readData(path);

代码示例来源：origin: apache/helix

@Test
public void testZkSessionExpiry() throws Exception {
 String className = TestHelper.getTestClassName();
 String methodName = TestHelper.getTestMethodName();
 String clusterName = className + "_" + methodName;
 System.out.println("START " + clusterName + " at " + new Date(System.currentTimeMillis()));
 ZkClient client =
   new ZkClient(ZK_ADDR, HelixZkClient.DEFAULT_SESSION_TIMEOUT,
     HelixZkClient.DEFAULT_CONNECTION_TIMEOUT, new ZNRecordSerializer());
 String path = String.format("/%s", clusterName);
 client.createEphemeral(path);
 String oldSessionId = ZkTestHelper.getSessionId(client);
 ZkTestHelper.expireSession(client);
 String newSessionId = ZkTestHelper.getSessionId(client);
 Assert.assertNotSame(newSessionId, oldSessionId);
 Assert.assertFalse(client.exists(path), "Ephemeral znode should be gone after session expiry");
 client.close();
 System.out.println("END " + clusterName + " at " + new Date(System.currentTimeMillis()));
}

代码示例来源：origin: org.apache.helix/helix-core

@Override
public boolean setInstanceConfig(String clusterName, String instanceName,
  InstanceConfig newInstanceConfig) {
 logger.info("Set instance config for instance {} to cluster {} with new InstanceConfig {}.",
   instanceName, clusterName,
   newInstanceConfig == null ? "NULL" : newInstanceConfig.toString());
 String instanceConfigPath = PropertyPathBuilder.getPath(PropertyType.CONFIGS, clusterName,
   HelixConfigScope.ConfigScopeProperty.PARTICIPANT.toString(), instanceName);
 if (!_zkClient.exists(instanceConfigPath)) {
  throw new HelixException(
    "instance" + instanceName + " does not exist in cluster " + clusterName);
 }
 HelixDataAccessor accessor =
   new ZKHelixDataAccessor(clusterName, new ZkBaseDataAccessor<ZNRecord>(_zkClient));
 PropertyKey instanceConfigPropertyKey = accessor.keyBuilder().instanceConfig(instanceName);
 InstanceConfig currentInstanceConfig = accessor.getProperty(instanceConfigPropertyKey);
 if (!newInstanceConfig.getHostName().equals(currentInstanceConfig.getHostName())
   || !newInstanceConfig.getPort().equals(currentInstanceConfig.getPort())) {
  throw new HelixException(
    "Hostname and port cannot be changed, current hostname: " + currentInstanceConfig
      .getHostName() + " and port: " + currentInstanceConfig.getPort()
      + " is different from new hostname: " + newInstanceConfig.getHostName()
      + "and new port: " + newInstanceConfig.getPort());
 }
 return accessor.setProperty(instanceConfigPropertyKey, newInstanceConfig);
}

代码示例来源：origin: org.apache.helix/helix-core

@Override
public void addInstance(String clusterName, InstanceConfig instanceConfig) {
 logger.info("Add instance {} to cluster {}.", instanceConfig.getInstanceName(), clusterName);
 if (!ZKUtil.isClusterSetup(clusterName, _zkClient)) {
  throw new HelixException("cluster " + clusterName + " is not setup yet");
 }
 String instanceConfigsPath = PropertyPathBuilder.instanceConfig(clusterName);
 String nodeId = instanceConfig.getId();
 String instanceConfigPath = instanceConfigsPath + "/" + nodeId;
 if (_zkClient.exists(instanceConfigPath)) {
  throw new HelixException("Node " + nodeId + " already exists in cluster " + clusterName);
 }
 ZKUtil.createChildren(_zkClient, instanceConfigsPath, instanceConfig.getRecord());
 _zkClient.createPersistent(PropertyPathBuilder.instanceMessage(clusterName, nodeId), true);
 _zkClient.createPersistent(PropertyPathBuilder.instanceCurrentState(clusterName, nodeId), true);
 _zkClient.createPersistent(PropertyPathBuilder.instanceError(clusterName, nodeId), true);
 _zkClient.createPersistent(PropertyPathBuilder.instanceStatusUpdate(clusterName, nodeId), true);
 _zkClient.createPersistent(PropertyPathBuilder.instanceHistory(clusterName, nodeId), true);
}