code: package io.ray.runtime.task;
  
  import com.google.common.base.Preconditions;
  import io.ray.api.exception.RayActorException;
  import io.ray.api.exception.RayException;
  import io.ray.api.exception.RayIntentionalSystemExitException;
  import io.ray.api.exception.RayTaskException;
  import io.ray.api.id.JobId;
  import io.ray.api.id.TaskId;
  import io.ray.api.id.UniqueId;
  import io.ray.runtime.AbstractRayRuntime;
  import io.ray.runtime.functionmanager.JavaFunctionDescriptor;
  import io.ray.runtime.functionmanager.RayFunction;
  import io.ray.runtime.generated.Common.TaskType;
  import io.ray.runtime.object.NativeRayObject;
  import io.ray.runtime.object.ObjectSerializer;
  import io.ray.runtime.util.NetworkUtil;
  import io.ray.runtime.util.SystemUtil;
  import java.lang.reflect.InvocationTargetException;
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  import java.util.stream.Collectors;
  import org.apache.commons.lang3.exception.ExceptionUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /** The task executor, which executes tasks assigned by raylet continuously. */
  public abstract class TaskExecutor<T extends TaskExecutor.ActorContext> {
  
    private static final Logger LOGGER = LoggerFactory.getLogger(TaskExecutor.class);
  
    protected final AbstractRayRuntime runtime;
  
    private T actorContext = null;
  
    private final ThreadLocal<RayFunction> localRayFunction = new ThreadLocal<>();
  
    static class ActorContext {
      /** The current actor object, if this worker is an actor, otherwise null. */
      Object currentActor = null;
    }
  
    TaskExecutor(AbstractRayRuntime runtime) {
      this.runtime = runtime;
    }
  
    protected abstract T createActorContext();
  
    T getActorContext() {
      return actorContext;
    }
  
    void setActorContext(UniqueId workerId, T actorContext) {
      if (actorContext == null) {
        // ConcurrentHashMap doesn't allow null values. So just return here.
        return;
      }
      this.actorContext = actorContext;
    }
  
    private RayFunction getRayFunction(List<String> rayFunctionInfo) {
      JobId jobId = runtime.getWorkerContext().getCurrentJobId();
      JavaFunctionDescriptor functionDescriptor = parseFunctionDescriptor(rayFunctionInfo);
      return runtime.getFunctionManager().getFunction(functionDescriptor);
    }
  
    /** The return value indicates which parameters are ByteBuffer. */
    protected boolean[] checkByteBufferArguments(List<String> rayFunctionInfo) {
      localRayFunction.set(null);
      try {
        localRayFunction.set(getRayFunction(rayFunctionInfo));
      } catch (Throwable e) {
        // Ignore the exception.
        return null;
      }
      Class<?>[] types = localRayFunction.get().executable.getParameterTypes();
      boolean[] results = new boolean[types.length];
      for (int i = 0; i < types.length; i++) {
        results[i] = types[i] == ByteBuffer.class;
      }
      return results;
    }
  
    private void throwIfDependencyFailed(Object arg) {
      if (arg instanceof RayException) {
        throw (RayException) arg;
      }
    }
  
    protected List<NativeRayObject> execute(List<String> rayFunctionInfo, List<Object> argsBytes) {
      TaskType taskType = runtime.getWorkerContext().getCurrentTaskType();
      TaskId taskId = runtime.getWorkerContext().getCurrentTaskId();
      LOGGER.debug("Executing task {} {}", taskId, rayFunctionInfo);
  
      T actorContext = null;
      if (taskType == TaskType.ACTOR_CREATION_TASK) {
        actorContext = createActorContext();
        setActorContext(runtime.getWorkerContext().getCurrentWorkerId(), actorContext);
      } else if (taskType == TaskType.ACTOR_TASK) {
        actorContext = getActorContext();
        Preconditions.checkNotNull(actorContext);
      }
  
      List<NativeRayObject> returnObjects = new ArrayList<>();
      // Find the executable object.
  
      RayFunction rayFunction = localRayFunction.get();
      Object[] args = null;
      try {
        // Find the executable object.
        if (rayFunction == null) {
          // Failed to get RayFunction in checkByteBufferArguments. Redo here to throw
          // the exception again.
          rayFunction = getRayFunction(rayFunctionInfo);
        }
        Thread.currentThread().setContextClassLoader(rayFunction.classLoader);
  
        // Get local actor object and arguments.
        Object actor = null;
        if (taskType == TaskType.ACTOR_TASK) {
          actor = actorContext.currentActor;
        }
        args = ArgumentsBuilder.unwrap(argsBytes, rayFunction.executable.getParameterTypes());
        for (Object arg : args) {
          throwIfDependencyFailed(arg);
        }
  
        // Execute the task.
        Object result;
        try {
          if (!rayFunction.isConstructor()) {
            result = rayFunction.getMethod().invoke(actor, args);
          } else {
            result = rayFunction.getConstructor().newInstance(args);
          }
        } catch (InvocationTargetException e) {
          if (e.getCause() != null) {
            throw e.getCause();
          } else {
            throw e;
          }
        }
  
        // Set result
        if (taskType != TaskType.ACTOR_CREATION_TASK) {
          if (rayFunction.hasReturn()) {
            returnObjects.add(ObjectSerializer.serialize(result));
          }
        } else {
          actorContext.currentActor = result;
        }
        LOGGER.debug("Finished executing task {}", taskId);
      } catch (Throwable e) {
        if (e instanceof RayIntentionalSystemExitException) {
          // We don't need to fill the `returnObjects` with an exception metadata
          // because the node manager or the direct actor task submitter will fill
          // the return object with the ACTOR_DIED metadata.
          throw (RayIntentionalSystemExitException) e;
        }
  
        final List<Class<?>> argTypes =
            args == null
                ? null
                : Arrays.stream(args)
                    .map(arg -> arg == null ? null : arg.getClass())
                    .collect(Collectors.toList());
        LOGGER.error(
            "Failed to execute task {} . rayFunction is {} , argument types are {}",
            taskId,
            rayFunction,
            argTypes,
            e);
  
        if (taskType != TaskType.ACTOR_CREATION_TASK) {
          boolean hasReturn = rayFunction != null && rayFunction.hasReturn();
          boolean isCrossLanguage = parseFunctionDescriptor(rayFunctionInfo).signature.equals("");
          if (hasReturn || isCrossLanguage) {
            NativeRayObject serializedException;
            try {
              serializedException =
                  ObjectSerializer.serialize(
                      new RayTaskException(
                          SystemUtil.pid(),
                          NetworkUtil.getIpAddress(null),
                          "Error executing task " + taskId,
                          e));
            } catch (Exception unserializable) {
              // We should try-catch `ObjectSerializer.serialize` here. Because otherwise if the
              // application-level exception is not serializable. `ObjectSerializer.serialize`
              // will throw an exception and crash the worker.
              // Refer to the case `TaskExceptionTest.java` for more details.
              LOGGER.warn("Failed to serialize the exception to a RayObject.", unserializable);
              serializedException =
                  ObjectSerializer.serialize(
                      new RayTaskException(
                          String.format(
                              "Error executing task %s with the exception: %s",
                              taskId, ExceptionUtils.getStackTrace(e))));
            }
            Preconditions.checkNotNull(serializedException);
            returnObjects.add(serializedException);
          } else {
            returnObjects.add(
                ObjectSerializer.serialize(
                    new RayTaskException(
                        SystemUtil.pid(),
                        NetworkUtil.getIpAddress(null),
                        String.format(
                            "Function %s of task %s doesn't exist",
                            String.join(".", rayFunctionInfo), taskId),
                        e)));
          }
        } else {
          throw new RayActorException(SystemUtil.pid(), NetworkUtil.getIpAddress(null), e);
        }
      }
      return returnObjects;
    }
  
    private JavaFunctionDescriptor parseFunctionDescriptor(List<String> rayFunctionInfo) {
      Preconditions.checkState(rayFunctionInfo != null && rayFunctionInfo.size() == 3);
      return new JavaFunctionDescriptor(
          rayFunctionInfo.get(0), rayFunctionInfo.get(1), rayFunctionInfo.get(2));
    }
  }
  