001/* -*- mode: Java; c-basic-offset: 2; indent-tabs-mode: nil; coding: utf-8-unix -*-
002 *
003 * Copyright © 2024 microBean™.
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
006 * the License. You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
011 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
012 * specific language governing permissions and limitations under the License.
013 */
014package org.microbean.bean;
015
016import java.lang.constant.ClassDesc;
017import java.lang.constant.Constable;
018import java.lang.constant.ConstantDesc;
019import java.lang.constant.DynamicConstantDesc;
020import java.lang.constant.MethodHandleDesc;
021
022import java.util.List;
023import java.util.Objects;
024import java.util.Optional;
025
026import javax.lang.model.element.Element;
027
028import javax.lang.model.type.TypeMirror;
029
030import org.microbean.constant.Constables;
031
032import org.microbean.qualifier.NamedAttributeMap;
033
034import static java.lang.constant.ConstantDescs.BSM_INVOKE;
035import static java.lang.constant.ConstantDescs.CD_List;
036
037import static org.microbean.lang.ConstantDescs.CD_Element;
038
039/**
040 * An {@link Element} that has been decorated with {@linkplain NamedAttributeMap attributes}.
041 *
042 * <p>Dependency injection frameworks often refer to this sort of thing as an <dfn>injection point</dfn>.</p>
043 *
044 * @param element a non-{@code null} {@link Element}
045 *
046 * @param attributes a non-{@code null} {@link List} of {@link NamedAttributeMap} instances representing attributes
047 *
048 * @author <a href="https://about.me/lairdnelson/" target="_top">Laird Nelson</a>
049 */
050public final record AttributedElement(Element element, List<NamedAttributeMap<?>> attributes) implements Constable {
051
052  public AttributedElement {
053    Objects.requireNonNull(element, "element");
054    attributes = List.copyOf(attributes);
055  }
056
057  public final TypeMirror type() {
058    return this.element().asType();
059  }
060
061  public final AttributedType attributedType() {
062    return new AttributedType(this.type(), this.attributes());
063  }
064
065  /**
066   * Returns an {@link Optional} containing a {@link ConstantDesc} describing this {@link AttributedType}, or an
067   * {@linkplain Optional#isEmpty() empty <code>Optional</code>} if it could not be described.
068   *
069   * @return an {@link Optional} containing a {@link ConstantDesc} describing this {@link AttributedType}, or an
070   * {@linkplain Optional#isEmpty() empty <code>Optional</code>} if it could not be describe; never {@code null}
071   */
072  @Override // Constable
073  public Optional<? extends ConstantDesc> describeConstable() {
074    return this.element() instanceof Constable e ? e.describeConstable() : Optional.<ConstantDesc>empty()
075      .flatMap(elementDesc -> Constables.describeConstable(this.attributes())
076               .map(attributesDesc -> DynamicConstantDesc.of(BSM_INVOKE,
077                                                             MethodHandleDesc.ofConstructor(ClassDesc.of(this.getClass().getName()),
078                                                                                            CD_Element,
079                                                                                            CD_List),
080                                                             elementDesc,
081                                                             attributesDesc)));
082  }
083
084}