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An unofficial backport of the JDK Classfile API to Java 17
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/*
 * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package io.github.dmlloyd.classfile.attribute;

import io.github.dmlloyd.classfile.Attribute;
import io.github.dmlloyd.classfile.ClassElement;
import io.github.dmlloyd.classfile.ClassModel;
import io.github.dmlloyd.classfile.impl.BoundAttribute;
import io.github.dmlloyd.classfile.impl.UnboundAttribute;
import io.github.dmlloyd.classfile.extras.PreviewFeature;

/**
 * Models the {@code ModuleResolution} attribute, which can
 * appear on classes that represent module descriptors.  This is a JDK-specific
 *  * attribute, which captures resolution metadata for modules.
 * Delivered as a {@link ClassElement} when
 * traversing the elements of a {@link ClassModel}.
 *
 *  The specification of the {@code ModuleResolution} attribute is:
 * 
 {@code
 *  ModuleResolution_attribute {
 *    u2 attribute_name_index;    // "ModuleResolution"
 *    u4 attribute_length;        // 2
 *    u2 resolution_flags;
 *
 *  The value of the resolution_flags item is a mask of flags used to denote
 *  properties of module resolution. The flags are as follows:
 *
 *   // Optional
 *   0x0001 (DO_NOT_RESOLVE_BY_DEFAULT)
 *
 *   // At most one of:
 *   0x0002 (WARN_DEPRECATED)
 *   0x0004 (WARN_DEPRECATED_FOR_REMOVAL)
 *   0x0008 (WARN_INCUBATING)
 *  }
 * } 
 * 
 * The attribute does not permit multiple instances in a given location.
 * Subsequent occurrence of the attribute takes precedence during the attributed
 * element build or transformation.
 *
 * @since 22
 */
@PreviewFeature(feature = PreviewFeature.Feature.CLASSFILE_API)
public sealed interface ModuleResolutionAttribute
        extends Attribute, ClassElement
        permits BoundAttribute.BoundModuleResolutionAttribute, UnboundAttribute.UnboundModuleResolutionAttribute {

    /**
     *  The value of the resolution_flags item is a mask of flags used to denote
     *  properties of module resolution. The flags are as follows:
     * 
 {@code
     *   // Optional
     *   0x0001 (DO_NOT_RESOLVE_BY_DEFAULT)
     *
     *   // At most one of:
     *   0x0002 (WARN_DEPRECATED)
     *   0x0004 (WARN_DEPRECATED_FOR_REMOVAL)
     *   0x0008 (WARN_INCUBATING)
     *  } 
     * @return the module resolution flags
     */
    int resolutionFlags();

    /**
     * {@return a {@code ModuleResolution} attribute}
     * @param resolutionFlags the resolution flags
     */
    static ModuleResolutionAttribute of(int resolutionFlags) {
        return new UnboundAttribute.UnboundModuleResolutionAttribute(resolutionFlags);
    }
}