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 com.android.server.inputmethod;
  
  import android.annotation.NonNull;
  import android.annotation.UserIdInt;
  import android.view.inputmethod.InputMethodInfo;
  
  import com.android.server.LocalServices;
  
  import java.util.Collections;
  import java.util.List;
  
  /**
   * Input method manager local system service interface.
   */
  public abstract class InputMethodManagerInternal {
      /**
       * Called by the power manager to tell the input method manager whether it
       * should start watching for wake events.
       */
      public abstract void setInteractive(boolean interactive);
  
      /**
       * Hides the current input method, if visible.
       */
      public abstract void hideCurrentInputMethod();
  
      /**
       * Returns the list of installed input methods for the specified user.
       *
       * @param userId The user ID to be queried.
       * @return A list of {@link InputMethodInfo}.  VR-only IMEs are already excluded.
       */
      public abstract List<InputMethodInfo> getInputMethodListAsUser(@UserIdInt int userId);
  
      /**
       * Returns the list of installed input methods that are enabled for the specified user.
       *
       * @param userId The user ID to be queried.
       * @return A list of {@link InputMethodInfo} that are enabled for {@code userId}.
       */
      public abstract List<InputMethodInfo> getEnabledInputMethodListAsUser(@UserIdInt int userId);
  
      /**
       * Fake implementation of {@link InputMethodManagerInternal}.  All the methods do nothing.
       */
      private static final InputMethodManagerInternal NOP =
              new InputMethodManagerInternal() {
                  @Override
                  public void setInteractive(boolean interactive) {
                  }
  
                  @Override
                  public void hideCurrentInputMethod() {
                  }
  
                  @Override
                  public List<InputMethodInfo> getInputMethodListAsUser(int userId) {
                      return Collections.emptyList();
                  }
  
                  @Override
                  public List<InputMethodInfo> getEnabledInputMethodListAsUser(int userId) {
                      return Collections.emptyList();
                  }
              };
  
      /**
       * @return Global instance if exists.  Otherwise, a dummy no-op instance.
       */
      @NonNull
      public static InputMethodManagerInternal get() {
          final InputMethodManagerInternal instance =
                  LocalServices.getService(InputMethodManagerInternal.class);
          return instance != null ? instance : NOP;
      }
  }
  