001/* -*- mode: Java; c-basic-offset: 2; indent-tabs-mode: nil; coding: utf-8-unix -*-
002 *
003 * Copyright © 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.assign;
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.Optional;
024
025import javax.lang.model.element.Element;
026
027import javax.lang.model.type.TypeMirror;
028
029import org.microbean.attributes.Attributed;
030import org.microbean.attributes.Attributes;
031
032import org.microbean.constant.Constables;
033
034import static java.lang.constant.ConstantDescs.BSM_INVOKE;
035import static java.lang.constant.ConstantDescs.CD_List;
036
037import static java.util.Objects.requireNonNull;
038
039/**
040 * A pairing of an {@link Element} with a {@link List} of {@link Attributes}s.
041 *
042 * @param element an {@link Element}
043 *
044 * @param attributes a {@link List} of {@link Attributes}s
045 *
046 * @author <a href="https://about.me/lairdnelson/" target="_top">Laird Nelson</a>
047 */
048public final record AttributedElement(Element element, List<Attributes> attributes) implements Attributed, AttributedTyped, Constable {
049
050  /**
051   * Creates a new {@link AttributedElement}.
052   *
053   * @param element a {@link Element}; must not be {@code null}
054   *
055   * @param attributes a {@link List} of {@link Attributes}; must not be {@code null}
056   *
057   * @exception NullPointerException if either argument is {@code null}
058   */
059  public AttributedElement {
060    requireNonNull(element, "element");
061    attributes = List.copyOf(attributes);
062  }
063
064  /**
065   * Returns this {@link AttributedElement}'s {@linkplain Element#asType() type}.
066   *
067   * @return this {@link AttributedElement}'s {@linkplain Element#asType() type}; never {@code null}
068   */
069  public final TypeMirror type() {
070    return this.element().asType();
071  }
072
073  /**
074   * Returns this {@link AttributedElement}'s {@link AttributedType}.
075   *
076   * @return this {@link AttributedElement}'s {@link AttributedType}; never {@code null}
077   *
078   * @see AttributedType
079   */
080  @Override // AttributedTyped
081  public final AttributedType attributedType() {
082    return new AttributedType(this.type(), this.attributes());
083  }
084
085  /**
086   * Returns an {@link Optional} containing a {@link ConstantDesc} describing this {@link AttributedType}, or an
087   * {@linkplain Optional#isEmpty() empty <code>Optional</code>} if it could not be described.
088   *
089   * @return an {@link Optional} containing a {@link ConstantDesc} describing this {@link AttributedType}, or an
090   * {@linkplain Optional#isEmpty() empty <code>Optional</code>} if it could not be describe; never {@code null}
091   */
092  @Override // Constable
093  public Optional<? extends ConstantDesc> describeConstable() {
094    return this.element() instanceof Constable e ? e.describeConstable() : Optional.<ConstantDesc>empty()
095      .flatMap(elementDesc -> Constables.describeConstable(this.attributes())
096               .map(attributesDesc -> DynamicConstantDesc.of(BSM_INVOKE,
097                                                             MethodHandleDesc.ofConstructor(ClassDesc.of(this.getClass().getName()),
098                                                                                            ClassDesc.of("javax.lang.model.element.Element"),
099                                                                                            CD_List),
100                                                             elementDesc,
101                                                             attributesDesc)));
102  }
103
104}