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.io.Serializable;
  import java.util.Objects;
  import java.util.Optional;
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.function.BooleanSupplier;
  import java.util.function.IntUnaryOperator;
  import java.util.function.LongUnaryOperator;
  import java.util.function.Supplier;
  import java.util.function.UnaryOperator;
  
  import org.jspecify.annotations.Nullable;
  
  import org.apache.causeway.commons.internal.exceptions._Exceptions;
  
  import lombok.AllArgsConstructor;
  import lombok.Data;
  import lombok.EqualsAndHashCode;
  import org.jspecify.annotations.NonNull;
  import lombok.Setter;
  import lombok.ToString;
  
  /**
   * <h1>- internal use only -</h1>
   * <p>
   * Not thread-safe, primitive and object references.
   * </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 _Refs {
  
      // -- FACTORIES
  
      public static BooleanReference booleanRef(final boolean value) {
          return new BooleanReference(value);
      }
  
      public static BooleanAtomicReference booleanAtomicRef(final boolean value) {
          return new BooleanAtomicReference(value);
      }
  
      public static IntReference intRef(final int value) {
          return new IntReference(value);
      }
  
      public static LongReference longRef(final int value) {
          return new LongReference(value);
      }
  
      public static <T> ObjectReference<T> objectRef(final @Nullable T value) {
          return new ObjectReference<>(value);
      }
  
      public static StringReference stringRef(final @NonNull String value) {
          return new StringReference(value);
      }
  
      // -- IMPLEMENTATIONS
  
      @FunctionalInterface
      public static interface BooleanUnaryOperator {
          boolean applyAsBoolean(boolean value);
      }
  
      /**
       * Holder of a mutable primitive {@code boolean} value.
       * @since 2.0
       */
      @Data @AllArgsConstructor
      public static final class BooleanReference {
          private boolean value;
  
          public boolean update(final @NonNull BooleanUnaryOperator operator) {
              return value = operator.applyAsBoolean(value);
          }
  
          public boolean isTrue() {
              return value;
          }
  
          public boolean isFalse() {
              return !value;
          }
      }
  
      /**
       * Serializable thread-safe boolean reference.
       * @apiNote unfortunately {@link AtomicBoolean} does not quite provide
       * conditional thread-safe value update
       */
      @AllArgsConstructor
      public static final class BooleanAtomicReference implements Serializable {
          private static final long serialVersionUID = 1L;
          private boolean value;
          private final Object $lock = new Object[0]; // serializable lock
  
          public boolean compute(final @NonNull BooleanUnaryOperator operator) {
              synchronized ($lock) {
                  return value = operator.applyAsBoolean(value);
              }
          }
  
          public boolean computeIfFalse(final @NonNull BooleanSupplier supplier) {
              synchronized ($lock) {
                  return value==false
                          ? value = supplier.getAsBoolean()
                          : true;
              }
          }
  
          public boolean computeIfTrue(final @NonNull BooleanSupplier supplier) {
              synchronized ($lock) {
                  return value==true
                          ? value = supplier.getAsBoolean()
                          : false;
              }
          }
  
          public boolean isTrue() {
              synchronized ($lock) {
                  return value;
              }
          }
  
          public boolean isFalse() {
              synchronized ($lock) {
                  return !value;
              }
          }
  
          @Override
          public boolean equals(final Object obj) {
              return obj instanceof BooleanAtomicReference
                  ? this.isTrue() == ((BooleanAtomicReference)obj).isTrue()
                  : false;
          }
  
          @Override
          public int hashCode() {
              return isTrue() ? 1 : -1;
          }
  
      }
  
      /**
       * Holder of a mutable primitive {@code int} value.
       * @since 2.0
       */
      @Data @AllArgsConstructor
      public static final class IntReference {
          private int value;
  
          public int update(final @NonNull IntUnaryOperator operator) {
              return value = operator.applyAsInt(value);
          }
  
          public boolean isSet(final int other) {
              return value==other;
          }
  
          public int incAndGet() {
              return ++value;
          }
  
          public int decAndGet() {
              return --value;
          }
  
          public int getAndInc() {
              return value++;
          }
  
          public int getAndDec() {
              return value--;
          }
      }
  
      /**
       * Holder of a mutable primitive {@code long} value.
       * @since 2.0
       */
      @Data @AllArgsConstructor
      public static final class LongReference {
          private long value;
  
          public long update(final @NonNull LongUnaryOperator operator) {
              return value = operator.applyAsLong(value);
          }
  
          public boolean isSet(final long other) {
              return value==other;
          }
  
          public long inc() {
              return ++value;
          }
  
          public long dec() {
              return --value;
          }
      }
  
      /**
       * Holder of a nullable and mutable {@link Object} value.
       * @since 2.0
       */
      @Setter @ToString @EqualsAndHashCode @AllArgsConstructor
      public static final class ObjectReference<T> {
          private @Nullable T value;
  
          public T set(final @Nullable T value) {
              return this.value = value;
          }
  
          public T update(final @NonNull UnaryOperator<T> operator) {
              return value = operator.apply(value);
          }
  
          public T computeIfAbsent(final @NonNull Supplier<T> factory) {
              return value!=null
                      ? value
                      : set(factory.get());
          }
  
          public boolean isNull() {
              return value==null;
          }
  
          public boolean isNotNull() {
              return value!=null;
          }
  
          public boolean isSet(final @Nullable T other) {
              return value==other;
          }
  
          public Optional<T> getValue() {
              return Optional.ofNullable(value);
          }
  
          public T getValueElseGet(final Supplier<? extends T> other) {
              return getValue().orElseGet(other);
          }
  
          public T getValueElseDefault(final T defaultValue) {
              return getValue().orElse(defaultValue);
          }
  
          public T getValueElseFail() {
              return getValue().orElseThrow(_Exceptions::noSuchElement);
          }
  
      }
  
      /**
       * Holder of a non-null and mutable {@link String} value.
       * @since 2.0
       */
      @Setter @ToString @EqualsAndHashCode @AllArgsConstructor
      public static final class StringReference {
          private @NonNull String value;
  
          public StringReference update(final @NonNull UnaryOperator<String> operator) {
              value = Objects.requireNonNull(operator.apply(value));
              return this;
          }
  
          public boolean isSet(final String other) {
              return value.equals(other);
          }
  
          public String getValue() {
              return value;
          }
  
          /**
           * Returns true if and only if this string contains the specified
           * sequence of char values.
           *
           * @param s the sequence to search for
           * @return true if this string contains {@code s}, false otherwise
           */
          public boolean contains(final CharSequence s) {
              return value.contains(s);
          }
  
      }
  
  }
  