content: /*
   * Copyright (C) 2022 The Android Open Source Project
   *
   * Licensed 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 androidx.test.espresso.util.concurrent;
  
  import static androidx.test.internal.util.Checks.checkNotNull;
  
  import androidx.annotation.RestrictTo;
  import androidx.annotation.RestrictTo.Scope;
  import java.util.Locale;
  import java.util.concurrent.Executors;
  import java.util.concurrent.ThreadFactory;
  import java.util.concurrent.atomic.AtomicLong;
  
  /**
   * A minimal implementation of Guava's ThreadFactoryBuilder
   *
   * @hide
   */
  @RestrictTo(Scope.LIBRARY)
  public class ThreadFactoryBuilder {
  
    private String nameFormat;
  
    public ThreadFactoryBuilder setNameFormat(String nameFormat) {
      String unused = format(nameFormat, 0); // fail fast if the format is bad or null
      this.nameFormat = nameFormat;
      return this;
    }
  
    public ThreadFactory build() {
      // espresso usages currently always set nameFormat, so lets just assert its nonnull to
      // simplify logic
      checkNotNull(nameFormat);
      ThreadFactory backingFactory = Executors.defaultThreadFactory();
      AtomicLong count = new AtomicLong(0);
      return r -> {
        Thread thread = backingFactory.newThread(r);
        thread.setName(format(nameFormat, count.getAndIncrement()));
        return thread;
      };
    }
  
    private static String format(String format, Object... args) {
      return String.format(Locale.ROOT, format, args);
    }
  }
  