src/java.base/share/classes/java/lang/classfile/attribute/PermittedSubclassesAttribute.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package java.lang.classfile.attribute;

import java.lang.classfile.Attribute;
import java.lang.classfile.AttributeMapper;
import java.lang.classfile.AttributeMapper.AttributeStability;
import java.lang.classfile.Attributes;
import java.lang.classfile.ClassElement;
import java.lang.classfile.ClassFile;
import java.lang.classfile.constantpool.ClassEntry;
import java.lang.constant.ClassDesc;
import java.util.Arrays;
import java.util.List;

import jdk.internal.classfile.impl.BoundAttribute;
import jdk.internal.classfile.impl.UnboundAttribute;
import jdk.internal.classfile.impl.Util;

/**
 * Models the {@link Attributes#permittedSubclasses() PermittedSubclasses}
 * attribute (JVMS {@jvms 4.7.31}), which indicates this class or interface
 * is {@linkplain java.compiler/javax.lang.model.element.Modifier#SEALED sealed},
 * and which classes or interfaces may extend or implement this class or
 * interface.
 * <p>
 * This attribute only appears on classes, and does not permit {@linkplain
 * AttributeMapper#allowMultiple multiple instances} in a class.  It has a
 * data dependency on the {@linkplain AttributeStability#CP_REFS constant pool}.
 * <p>
 * The attribute was introduced in the Java SE Platform version 17, major
 * version {@value ClassFile#JAVA_17_VERSION}.
 *
 * @see Attributes#permittedSubclasses()
 * @see Class#isSealed()
 * @see Class#getPermittedSubclasses()
 * @jls 8.1.1.2 {@code sealed}, {@code non-sealed}, and {@code final} Classes
 * @jls 9.1.1.4 {@code sealed} and {@code non-sealed} Interfaces
 * @jvms 4.7.31 The {@code PermittedSubclasses} Attribute
 * @since 24
 */
@SuppressWarnings("doclint:reference")
public sealed interface PermittedSubclassesAttribute
        extends Attribute<PermittedSubclassesAttribute>, ClassElement
        permits BoundAttribute.BoundPermittedSubclassesAttribute, UnboundAttribute.UnboundPermittedSubclassesAttribute {

    /**
     * {@return the list of permitted subclasses or subinterfaces}
     *
     * @see Class#getPermittedSubclasses()
     */
    List<ClassEntry> permittedSubclasses();

    /**
     * {@return a {@code PermittedSubclasses} attribute}
     *
     * @param permittedSubclasses the permitted subclasses or subinterfaces
     */
    static PermittedSubclassesAttribute of(List<ClassEntry> permittedSubclasses) {
        return new UnboundAttribute.UnboundPermittedSubclassesAttribute(permittedSubclasses);
    }

    /**
     * {@return a {@code PermittedSubclasses} attribute}
     *
     * @param permittedSubclasses the permitted subclasses or subinterfaces
     */
    static PermittedSubclassesAttribute of(ClassEntry... permittedSubclasses) {
        return of(List.of(permittedSubclasses));
    }

    /**
     * {@return a {@code PermittedSubclasses} attribute}
     *
     * @param permittedSubclasses the permitted subclasses or subinterfaces
     * @throws IllegalArgumentException if any of {@code permittedSubclasses} is primitive
     */
    static PermittedSubclassesAttribute ofSymbols(List<ClassDesc> permittedSubclasses) {
        return of(Util.entryList(permittedSubclasses));
    }

    /**
     * {@return a {@code PermittedSubclasses} attribute}
     *
     * @param permittedSubclasses the permitted subclasses or subinterfaces
     * @throws IllegalArgumentException if any of {@code permittedSubclasses} is primitive
     */
    static PermittedSubclassesAttribute ofSymbols(ClassDesc... permittedSubclasses) {
        // List version does defensive copy
        return ofSymbols(Arrays.asList(permittedSubclasses));
    }
}