content: /*
   * Copyright (C) 2015 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.runner.intent;
  
  import java.util.concurrent.atomic.AtomicReference;
  
  /** Exposes an implementation of {@link IntentMonitor} to users. */
  public final class IntentMonitorRegistry {
  
    private static final AtomicReference<IntentMonitor> monitorRef =
        new AtomicReference<IntentMonitor>(null);
  
    /**
     * Returns the IntentMonitor. This monitor is not guaranteed to be present under all'
     * instrumentations.
     *
     * @throws IllegalStateException if no monitor has been registered.
     */
    public static IntentMonitor getInstance() {
      IntentMonitor instance = monitorRef.get();
      if (null == instance) {
        throw new IllegalStateException(
            "No intent monitor registered! Are you running under an "
                + "Instrumentation which registers intent monitors?");
      }
      return instance;
    }
  
    /**
     * Stores the given {@link IntentMonitor} instance in the registry. Passing null removes the
     * monitor from the registry.
     */
    public static void registerInstance(IntentMonitor monitor) {
      monitorRef.set(monitor);
    }
  
    private IntentMonitorRegistry() {
      // no instance
    }
  }
  