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 android.service.autofill;
  
  import android.annotation.NonNull;
  
  import com.android.internal.util.Preconditions;
  
  /**
   * Factory for {@link Validator} operations.
   *
   * <p>See {@link SaveInfo.Builder#setValidator(Validator)} for examples.
   */
  public final class Validators {
  
      private Validators() {
          throw new UnsupportedOperationException("contains static methods only");
      }
  
      /**
       * Creates a validator that is only valid if all {@code validators} are valid.
       *
       * <p>Used to represent an {@code AND} boolean operation in a chain of validators.
       *
       * @throws IllegalArgumentException if any element of {@code validators} is an instance of a
       * class that is not provided by the Android System.
       */
      @NonNull
      public static Validator and(@NonNull Validator...validators) {
          return new RequiredValidators(getInternalValidators(validators));
      }
  
      /**
       * Creates a validator that is valid if any of the {@code validators} is valid.
       *
       * <p>Used to represent an {@code OR} boolean operation in a chain of validators.
       *
       * @throws IllegalArgumentException if any element of {@code validators} is an instance of a
       * class that is not provided by the Android System.
       */
      @NonNull
      public static Validator or(@NonNull Validator...validators) {
          return new OptionalValidators(getInternalValidators(validators));
      }
  
      /**
       * Creates a validator that is valid when {@code validator} is not, and vice versa.
       *
       * <p>Used to represent a {@code NOT} boolean operation in a chain of validators.
       *
       * @throws IllegalArgumentException if {@code validator} is an instance of a class that is not
       * provided by the Android System.
       */
      @NonNull
      public static Validator not(@NonNull Validator validator) {
          Preconditions.checkArgument(validator instanceof InternalValidator,
                  "validator not provided by Android System: " + validator);
          return new NegationValidator((InternalValidator) validator);
      }
  
      private static InternalValidator[] getInternalValidators(Validator[] validators) {
          Preconditions.checkArrayElementsNotNull(validators, "validators");
  
          final InternalValidator[] internals = new InternalValidator[validators.length];
  
          for (int i = 0; i < validators.length; i++) {
              Preconditions.checkArgument((validators[i] instanceof InternalValidator),
                      "element " + i + " not provided by Android System: " + validators[i]);
              internals[i] = (InternalValidator) validators[i];
          }
          return internals;
      }
  }
  