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.ioc;
  
  import java.util.Objects;
  import java.util.Optional;
  import java.util.function.Predicate;
  import java.util.function.Supplier;
  
  import org.jspecify.annotations.NonNull;
  import org.jspecify.annotations.Nullable;
  
  import org.apache.causeway.commons.internal.exceptions._Exceptions;
  
  /**
   * @since 2.0
   */
  public record _SingletonBeanProvider(
          /**
           * Unique bean name (not an alias).
           * Corresponds to the logical-type-name (Causeway semantics).
           */
          @NonNull String id,
          @NonNull Class<?> beanClass,
  
          //@ToString.Exclude @EqualsAndHashCode.Exclude
          @NonNull Supplier<?> beanProvider) {
  
      // -- TEST FACTORIES
  
      public static <T> _SingletonBeanProvider forTestingLazy(
              final String logicalTypeName, final Class<T> beanClass, final Supplier<T> beanProvider) {
          return new _SingletonBeanProvider(logicalTypeName, beanClass, beanProvider);
      }
  
      public static <T> _SingletonBeanProvider forTestingLazy(
              final Class<T> beanClass, final Supplier<T> beanProvider) {
          return new _SingletonBeanProvider(beanClass.getName(), beanClass, beanProvider);
      }
  
      public static <T> _SingletonBeanProvider forTesting(final T bean) {
          return new _SingletonBeanProvider(bean.getClass().getName(), bean.getClass(), ()->bean);
      }
  
      public Optional<?> lookupInstance() {
          return Optional.ofNullable(beanProvider.get());
      }
  
      public Object getInstanceElseFail() {
          return lookupInstance().orElseThrow(
                  ()->_Exceptions.noSuchElement("Cannot create bean instance for name '%s' (with required type %s)",
                          id,
                          beanClass.getName()));
      }
  
      public boolean isCandidateFor(final @Nullable Class<?> requiredType) {
          if(requiredType==null) return false;
          return requiredType.isAssignableFrom(beanClass);
      }
  
      @Override
      public final boolean equals(final Object obj) {
          return obj instanceof _SingletonBeanProvider other
                  ? Objects.equals(this.id(), other.id())
                          && Objects.equals(this.beanClass(), other.beanClass())
                  : false;
      }
      @Override
      public final int hashCode() {
          return Objects.hash(id, beanClass);
      }
      @Override
      public final String toString() {
          return "SingletonBeanProvider[id=%s, beanClass=%s]".formatted(id, beanClass);
      }
  
      // -- UTILITY
  
      public static Predicate<_SingletonBeanProvider> satisfying(final Class<?> requiredType) {
          return singletonProvider->singletonProvider.isCandidateFor(requiredType);
      }
  
  }