content: /*
   * Copyright (C) 2017 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;
  
  import static java.util.Collections.synchronizedSet;
  
  import android.os.Looper;
  import android.util.Log;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Set;
  
  /**
   * Handles registering and unregistering of {@link IdlingResource}s with Espresso from within your
   * application code.
   *
   * <p>These resources are required by Espresso to provide synchronisation against your application
   * code. All registered resources with this registry will be automatically synchronized against for
   * each Espresso interaction.
   *
   * <p>This registry along with {@link IdlingResource} interface are bundled together in a small
   * light weight module so that it can be pulled in as a dependency of the App under test with close
   * to no overhead.
   */
  public final class IdlingRegistry {
  
    private static final String TAG = IdlingRegistry.class.getSimpleName();
    private static final IdlingRegistry instance = new IdlingRegistry();
    private final Set<IdlingResource> resources = synchronizedSet(new HashSet<IdlingResource>());
    private final Set<Looper> loopers = synchronizedSet(new HashSet<Looper>());
  
    // VisibleForTesting
    IdlingRegistry() {}
  
    /**
     * Returns a singleton instance of this {@link IdlingRegistry} that should be globally used for
     * registering and unregistering {@link IdlingResource}s
     */
    public static IdlingRegistry getInstance() {
      return instance;
    }
  
    /**
     * Registers one or more {@link IdlingResource}s. When registering more than one resource, ensure
     * that each has a unique name returned from {@link IdlingResource#getName()}
     *
     * @return {@code true} if at least one resource was successfully added to the registry
     */
    public boolean register(IdlingResource... idlingResources) {
      if (null == idlingResources) {
        throw new NullPointerException("idlingResources cannot be null!");
      }
      Log.d(TAG, "Registering idling resources: " + Arrays.toString(idlingResources));
      return resources.addAll(Arrays.asList(idlingResources));
    }
  
    /**
     * Unregisters one or more {@link IdlingResource}s.
     *
     * @return {@code true} if at least one resource was successfully removed from the registry
     */
    public boolean unregister(IdlingResource... idlingResources) {
      if (null == idlingResources) {
        throw new NullPointerException("idlingResources cannot be null!");
      }
      Log.d(TAG, "Unregistering idling resources: " + Arrays.toString(idlingResources));
      return resources.removeAll(Arrays.asList(idlingResources));
    }
  
    /**
     * Registers a {@link Looper} for idle checking with the framework. This is intended for use with
     * non-UI thread {@link Looper}s only.
     *
     * @throws IllegalArgumentException if looper is the main looper.
     * @throws NullPointerException if looper is null.
     */
    public void registerLooperAsIdlingResource(Looper looper) {
      if (null == looper) {
        throw new NullPointerException("looper cannot be null!");
      }
      if (Looper.getMainLooper() == looper) {
        throw new IllegalArgumentException("Not intended for use with main looper!");
      }
  
      loopers.add(looper);
    }
  
    /**
     * Unregisters a {@link Looper}.
     *
     * <p>Attempting to unregister a looper that is not registered is a no-op.
     *
     * @return {@code true} if the looper was successfully removed from the registry
     */
    public boolean unregisterLooperAsIdlingResource(Looper looper) {
      if (null == looper) {
        throw new NullPointerException("looper cannot be null!");
      }
      return loopers.remove(looper);
    }
  
    /** Returns a set of all currently registered {@link IdlingResource}s. */
    public Collection<IdlingResource> getResources() {
      synchronized (resources) {
        return new HashSet<>(resources);
      }
    }
  
    /** Returns a set of all currently registered {@link Looper}s. */
    public Collection<Looper> getLoopers() {
      synchronized (loopers) {
        return new HashSet<>(loopers);
      }
    }
  }
  