content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   *
   *    http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.kafka.coordinator.common.runtime;
  
  import java.util.ArrayDeque;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Queue;
  
  public class MockCoordinatorExecutor<T> implements CoordinatorExecutor<T> {
      private class ExecutorTask<R> {
          public final String key;
          public final TaskRunnable<R> task;
          public final TaskOperation<T, R> operation;
  
          ExecutorTask(
              String key,
              TaskRunnable<R> task,
              TaskOperation<T, R> operation
          ) {
              this.key = Objects.requireNonNull(key);
              this.task = Objects.requireNonNull(task);
              this.operation = Objects.requireNonNull(operation);
          }
  
          CoordinatorResult<Void, T> execute() {
              try {
                  return operation.onComplete(task.run(), null);
              } catch (Throwable ex) {
                  return operation.onComplete(null, ex);
              }
          }
      }
  
      public static class ExecutorResult<T> {
          public final String key;
          public final CoordinatorResult<Void, T> result;
  
          public ExecutorResult(
              String key,
              CoordinatorResult<Void, T> result
          ) {
              this.key = Objects.requireNonNull(key);
              this.result = Objects.requireNonNull(result);
          }
  
          @Override
          public boolean equals(Object o) {
              if (this == o) return true;
              if (o == null || getClass() != o.getClass()) return false;
  
              ExecutorResult<?> that = (ExecutorResult<?>) o;
  
              if (!Objects.equals(key, that.key)) return false;
              return Objects.equals(result, that.result);
          }
  
          @Override
          public int hashCode() {
              int result = key.hashCode();
              result = 31 * result + this.result.hashCode();
              return result;
          }
  
          @Override
          public String toString() {
              return "ExecutorResult(" +
                  "key='" + key + '\'' +
                  ", result=" + result +
                  ')';
          }
      }
  
      private final Map<String, TaskRunnable<?>> tasks = new HashMap<>();
      private final Queue<ExecutorTask<?>> queue = new ArrayDeque<>();
  
      @Override
      public <R> boolean schedule(
          String key,
          TaskRunnable<R> task,
          TaskOperation<T, R> operation
      ) {
          if (tasks.putIfAbsent(key, task) != null) return false;
          return queue.add(new ExecutorTask<>(key, task, operation));
      }
  
      @Override
      public boolean isScheduled(String key) {
          return tasks.containsKey(key);
      }
  
      public int size() {
          return queue.size();
      }
  
      @Override
      public void cancel(String key) {
          tasks.remove(key);
      }
  
      public List<ExecutorResult<T>> poll() {
          List<ExecutorResult<T>> results = new ArrayList<>();
          for (ExecutorTask<?> task : queue) {
              tasks.remove(task.key, task.task);
              results.add(new ExecutorResult<>(task.key, task.execute()));
          }
          queue.clear();
          return results;
      }
  }
  