content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you 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 org.apache.causeway.commons.internal.base;
  
  import java.util.Optional;
  import java.util.function.BiFunction;
  
  import org.jspecify.annotations.Nullable;
  
  import org.jspecify.annotations.NonNull;
  
  /**
   * <h1>- internal use only -</h1>
   * <p>
   * Casting Utilities
   * </p>
   * <p>
   * <b>WARNING</b>: Do <b>NOT</b> use any of the classes provided by this package! <br/>
   * These may be changed or removed without notice!
   * </p>
   *
   * @since 2.0
   */
  public final class _Casts {
  
      private _Casts(){}
  
      @SuppressWarnings("unchecked")
      public static <T> T uncheckedCast(final @Nullable Object obj) {
          return (T) obj;
      }
  
      /**
       * Casts an object to the class or interface represented by given {@code cls} Class object,
       * then wraps the result in an {@link Optional}. The {@link Optional} is empty if the cast
       * fails or provided {@code value} is {@code null}.
       * @param <T>
       * @param value
       * @param cls
       * @return non-null
       */
      public static <T> Optional<T> castTo(final @NonNull Class<T> cls, final @Nullable Object value) {
          if(value==null) {
              return Optional.empty();
          }
          if(cls.isAssignableFrom(value.getClass())) {
              return Optional.of(cls.cast(value));
          }
          return Optional.empty();
      }
  
      /**
       * Casts an object to the class or interface represented by given {@code cls} Class object.
       * Returns {@code null}, if the cast fails or provided {@code value} is {@code null}.
       * @param <T>
       * @param value
       * @param cls
       * @return casted value, or null
       */
      public static @Nullable <T> T castToOrElseNull(final @Nullable Object value, final @NonNull Class<T> cls) {
          if(value==null) {
              return null;
          }
          if(cls.isAssignableFrom(value.getClass())) {
              return cls.cast(value);
          }
          return null;
      }
  
      /**
       * Dependent on whether left or right can be cast to {@code cls}, the appropriate functional
       * interface is chosen to produce the result.
       * @param left
       * @param right
       * @param cls
       * @param onBothCast
       * @param onLeftCast
       * @param onRightCast
       * @param onNonCast
       */
      public static <T, R, U, V> R castThenApply(
              final @Nullable U left,
              final @Nullable V right,
              final @NonNull Class<T> cls,
              final BiFunction<T, T, R> onBothCast,
              final BiFunction<T, V, R> onLeftCast,
              final BiFunction<U, T, R> onRightCast,
              final BiFunction<U, V, R> onNonCast) {
  
          T left_casted=null, right_casted=null;
          boolean left_not_casted=false, right_not_casted=false;
  
          if(left==null) {
              left_casted = null;
          } else if(cls.isAssignableFrom(left.getClass())) {
              left_casted = cls.cast(left);
          } else {
              left_not_casted = true;
          }
  
          if(right==null) {
              right_casted = null;
          } else if(cls.isAssignableFrom(right.getClass())) {
              right_casted = cls.cast(right);
          } else {
              right_not_casted = true;
          }
  
          if(left_not_casted && right_not_casted) {
              return onNonCast.apply(left, right);
          }
  
          if(!left_not_casted && !right_not_casted) {
              return onBothCast.apply(left_casted, right_casted);
          }
  
          if(left_not_casted) {
              return onRightCast.apply(left, right_casted);
          }
  
          return onLeftCast.apply(left_casted, right);
  
      }
  
  }
  