001/* -*- mode: Java; c-basic-offset: 2; indent-tabs-mode: nil; coding: utf-8-unix -*-
002 *
003 * Copyright © 2024–2025 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.attributes.Attributed;
031import org.microbean.attributes.Attributes;
032
033import org.microbean.constant.Constables;
034
035import static java.lang.constant.ConstantDescs.BSM_INVOKE;
036import static java.lang.constant.ConstantDescs.CD_List;
037
038/**
039 * A pairing of an {@link Element} with a {@link List} of {@link Attributes}s.
040 *
041 * @param element an {@link Element}
042 *
043 * @param attributes a {@link List} of {@link Attributes}s
044 *
045 * @author <a href="https://about.me/lairdnelson/" target="_top">Laird Nelson</a>
046 */
047public final record AttributedElement(Element element, List<Attributes> attributes) implements Attributed, Constable {
048
049  /**
050   * Creates a new {@link AttributedElement}.
051   *
052   * @param element a {@link Element}; must not be {@code null}
053   *
054   * @param attributes a {@link List} of {@link Attributes}; must not be {@code null}
055   *
056   * @exception NullPointerException if either argument is {@code null}
057   */
058  public AttributedElement {
059    Objects.requireNonNull(element, "element");
060    attributes = List.copyOf(attributes);
061  }
062
063  /**
064   * Returns this {@link AttributedElement}'s {@linkplain Element#asType() type}.
065   *
066   * @return this {@link AttributedElement}'s {@linkplain Element#asType() type}; never {@code null}
067   */
068  public final TypeMirror type() {
069    return this.element().asType();
070  }
071
072  /**
073   * Returns this {@link AttributedElement}'s {@link AttributedType}.
074   *
075   * @return this {@link AttributedElement}'s {@link AttributedType}; never {@code null}
076   *
077   * @see AttributedType
078   */
079  public final AttributedType attributedType() {
080    return new AttributedType(this.type(), this.attributes());
081  }
082
083  /**
084   * Returns an {@link Optional} containing a {@link ConstantDesc} describing this {@link AttributedType}, or an
085   * {@linkplain Optional#isEmpty() empty <code>Optional</code>} if it could not be described.
086   *
087   * @return an {@link Optional} containing a {@link ConstantDesc} describing this {@link AttributedType}, or an
088   * {@linkplain Optional#isEmpty() empty <code>Optional</code>} if it could not be describe; never {@code null}
089   */
090  @Override // Constable
091  public Optional<? extends ConstantDesc> describeConstable() {
092    return this.element() instanceof Constable e ? e.describeConstable() : Optional.<ConstantDesc>empty()
093      .flatMap(elementDesc -> Constables.describeConstable(this.attributes())
094               .map(attributesDesc -> DynamicConstantDesc.of(BSM_INVOKE,
095                                                             MethodHandleDesc.ofConstructor(ClassDesc.of(this.getClass().getName()),
096                                                                                            ClassDesc.of("javax.lang.model.element.Element"),
097                                                                                            CD_List),
098                                                             elementDesc,
099                                                             attributesDesc)));
100  }
101
102}