return methods_.summarize != nullptr;
  }

  absl::Status SummarizeValue(std::string& summary) const override {
    if (methods_.summarize == nullptr) {
      return tensorflow::CustomDeviceTensorHandle::SummarizeValue(summary);
    }
    TF_Status c_status;
    std::unique_ptr<TF_Buffer, decltype(&TF_DeleteBuffer)> summary_buffer(
        methods_.summarize(data_, &c_status), TF_DeleteBuffer);

  TFE_CustomDeviceTensorHandleMethods handle_methods;
  handle_methods.num_dims = &ParallelTensorNumDims;
  handle_methods.dim = &ParallelTensorDim;
  handle_methods.deallocator = &ParallelTensorDeallocator;
  handle_methods.summarize = &ParallelTensorSummarize;
  return TensorHandlePtr(TFE_NewCustomDeviceTensorHandle(
      context, parallel_device_name.c_str(), t_released->dtype(), t_released,
      handle_methods, status));
}

  // device which would be useful for debugging.
  //
  // Optional. If null, defaults to resolving the TFE_TensorHandle into a
  // TF_Tensor and summarizing that.
  TF_Buffer* (*summarize)(void* data, TF_Status* status) = nullptr;
} TFE_CustomDeviceTensorHandle;

// Creates a new TensorHandle from memory residing in a custom device. Takes

 * forms of variance -- that were computed from a single set of zero or more floating-point values.
 *
 * <p>There are two ways to obtain a {@code Stats} instance:
 *
 * <ul>
 *   <li>If all the values you want to summarize are already known, use the appropriate {@code
 *       Stats.of} factory method below. Primitive arrays, iterables and iterators of any kind of
 *       {@code Number}, and primitive varargs are supported.

 */
package org.apache.maven.execution;

import java.util.Objects;

import org.apache.maven.project.MavenProject;

/**
 * Summarizes the result of a project build in the reactor.
 *
 */
public abstract class BuildSummary {

    /**
     * The project being summarized.
     */
    private final MavenProject project;

    /**
     * The build time of the project in milliseconds.
     */

package org.apache.maven.execution;

import org.apache.maven.project.MavenProject;

/**
 * Summarizes the result of a successful project build in the reactor.
 *
 */
public class BuildSuccess extends BuildSummary {

    /**
     * Creates a new build summary for the specified project.
     *
     * @param project The project being summarized, must not be {@code null}.
     * @param time The build time of the project in milliseconds.

/**
 * Summarizes the result of a failed project build in the reactor.
 *
 */
public class BuildFailure extends BuildSummary {

    /**
     * The cause of the build failure.
     */
    private final Throwable cause;

    /**
     * Creates a new build summary for the specified project.
     *
     * @param project The project being summarized, must not be {@code null}.

 * <a href="http://cwiki.apache.org/confluence/display/MAVEN/">http://cwiki.apache.org/confluence/display/MAVEN/</a>,
 * </li>
 * <li>child exception summaries.</li>
 * </ul>
 */
public class ExceptionSummary {

    private Throwable exception;

    private String message;

    private String reference;

    private List<ExceptionSummary> children;

  // the handle loses information, but `SummarizeValue` would be more precise.
  virtual bool PreferCustomSummarizer() const { return false; }

  // Returns a string which summarizes the value of this TensorHandle, for
  // debugging. Does not include a shape or dtype.
  //
  // Included in the default implementation of DebugString.
  virtual absl::Status SummarizeValue(std::string& summary) const;

  ImmediateExecutionTensorHandle* unwrapped_handle =
      tensorflow::unwrap(device_value.get());
  std::string summarized;
  TF_ASSERT_OK(unwrapped_handle->SummarizeValue(summarized));
  EXPECT_THAT(summarized, HasSubstr("\"CPU:0\": 3"));
}

}  // namespace parallel_device