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Shaded fat Jar for pkl-config-java, a Java config library based on the Pkl config language.
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/*
 * Copyright (c) 2013, 2020, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * The Universal Permissive License (UPL), Version 1.0
 *
 * Subject to the condition set forth below, permission is hereby granted to any
 * person obtaining a copy of this software, associated documentation and/or
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 * copyright rights in the Software, and any and all patent rights owned or
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 * unmodified Software as contributed to or provided by such licensor, or (ii)
 * the Larger Works (as defined below), to deal in both
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 * (a) the Software, and
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 * is contributed by such licensors),
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package org.pkl.thirdparty.truffle.api.utilities;

/**
 * An utility value with three states, {@link #TRUE}, {@link #FALSE}, and {@link #UNDEFINED}.
 * {@link TriState} is preferable to using a {@link Boolean} value with {@link Boolean#TRUE},
 * {@link Boolean#FALSE} and null, because {@link Boolean} has a public constructor
 * which requires the use of {@link Boolean#equals(Object)} to compare the values. The comparison
 * with {@link Boolean#equals(Object)} is too slow.
 *
 * @since 20.2
 */
public enum TriState {

    /**
     * The state is true. Similar to {@link Boolean#TRUE}.
     *
     * @since 20.2
     */
    TRUE,

    /**
     * The state is false. Similar to {@link Boolean#FALSE}.
     *
     * @since 20.2
     */
    FALSE,

    /**
     * The state is undefined. Similar to null.
     *
     * @since 20.2
     */
    UNDEFINED;

    /**
     * Create a {@link TriState} from a primitive boolean.
     *
     * @since 20.2
     */
    public static TriState valueOf(boolean b) {
        return b ? TRUE : FALSE;
    }

    /**
     * Create a {@link TriState} from a boxed {@link Boolean} explicitely checking for
     * null and returning {@link #UNDEFINED}.
     *
     * @since 20.2
     */
    public static TriState valueOf(Boolean b) {
        return b == null ? UNDEFINED : (Boolean.TRUE.equals(b) ? TRUE : FALSE);
    }

}