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This project contains a parser for the Checker Framework's stub files: https://checkerframework.org/manual/#stub . It is a fork of the JavaParser project.
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/*
 * Copyright (C) 2007-2010 Júlio Vilmar Gesser.
 * Copyright (C) 2011, 2013-2024 The JavaParser Team.
 *
 * This file is part of JavaParser.
 *
 * JavaParser can be used either under the terms of
 * a) the GNU Lesser General Public License as published by
 *     the Free Software Foundation, either version 3 of the License, or
 *     (at your option) any later version.
 * b) the terms of the Apache License
 *
 * You should have received a copy of both licenses in LICENCE.LGPL and
 * LICENCE.APACHE. Please refer to those files for details.
 *
 * JavaParser 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 Lesser General Public License for more details.
 */
package com.github.javaparser.printer.lexicalpreservation.changes;

import com.github.javaparser.ast.Node;
import com.github.javaparser.ast.observer.ObservableProperty;
import com.github.javaparser.printer.concretesyntaxmodel.CsmConditional;
import com.github.javaparser.utils.Utils;

/**
 * This represents a change that has happened to a specific Node.
 */
public interface Change {

    default boolean evaluate(CsmConditional csmConditional, Node node) {
        switch (csmConditional.getCondition()) {
            case FLAG:
                return csmConditional.getProperties().stream().anyMatch(p -> (Boolean) getValue(p, node));
            case IS_NOT_EMPTY:
                return !Utils.valueIsNullOrEmpty(getValue(csmConditional.getProperty(), node));
            case IS_EMPTY:
                return Utils.valueIsNullOrEmpty(getValue(csmConditional.getProperty(), node));
            case IS_PRESENT:
                return !Utils.valueIsNullOrEmptyStringOrOptional(getValue(csmConditional.getProperty(), node))
                        && !isEvaluatedOnDerivedProperty(csmConditional.getProperty());
            default:
                throw new UnsupportedOperationException(
                        "" + csmConditional.getProperty() + " " + csmConditional.getCondition());
        }
    }

    /*
     * Evaluate on derived property.
     *
     * Currently the evaluation of the conditions is carried out in relation to the
     * presence of value in the field/attribute of a class referenced by a property
     * (for example the BODY property is referenced to the body field in the
     * LambdaExpr class) but this is not quite correct.
     *
     * Indeed, there are attributes that are derived. The meaning of a derived
     * attribute (annotated with the DerivedProperty annotation) is not very clear.
     * Assuming that it is an existing attribute and accessible by another property,
     * for example this is the case for the EXPRESSION_BODY property which allows
     * access to a derived field (which is also accessible by the BODY property).
     *
     * The 2 properties EXPRESSION_BODY and BODY have a different meaning because
     * one references a simple expression while the other references a list of
     * expressions (this distinction is particularly interesting in the case of
     * lambda expressions).
     *
     * In this particular case, the verification of the condition defined in the
     * syntax model used by LPP must not succeed if the nature of the property is
     * modified. So if we modify a lamba expression composed of a single expression
     * by replacing it with a list of expressions, the evaluation of a condition
     * relating to the presence of the EXPRESSION_BODY property, which makes it
     * possible to determine the nature of the change, cannot not lead to a verified
     * proposition which could be the case if we only consider that the field
     * referenced by the EXPRESSION_BODY property has an acceptable value before the
     * actual modification.
     *
     * This is why we also check if it is a derived property whose name coincides
     * (*) with the updated property. If this is the case, we admit that the
     * verification of the condition must fail so that we can execute the else
     * clause of the condition. I'm not sure this issue #3949 is completely resolved
     * by this change.
     *
     * (*) Assuming that by convention the derived property is suffixed with the
     * name of the property it derives from (e.g.. EXPRESSION_BODY which matches an
     * expression would derive from BODY which matches a list of expressions), we
     * could deduce that EXPRESSION_BODY and BODY actually represent the same field
     * but the validation condition must not be checked.
     */
    default boolean isEvaluatedOnDerivedProperty(ObservableProperty property) {
        ObservableProperty currentProperty = getProperty();
        /*
         * By convention we admit that the derived property is suffixed with the name of
         * the property it derives from (e.g. EXPRESSION_BODY which matches an
         * expression would derive from BODY which matches a list of expressions), so we
         * could deduce that EXPRESSION_BODY and BODY actually represent the same
         * field but the validation condition must not be checked.
         * Be careful because NoChange property must not affect this evaluation.
         */
        return currentProperty != null
                && (property.isDerived() && property.name().endsWith(currentProperty.name()));
    }

    /*
     * Assuming that by convention the derived property is suffixed
     * with the name of the property it derives from (e.g. EXPRESSION_BODY which
     * matches an expression vs a list of expressions would derive from BODY) We
     * could deduce that EXPRESSION_BODY and BODY actually represent the same
     * property but the validation condition is not checked.
     */
    ObservableProperty getProperty();

    Object getValue(ObservableProperty property, Node node);
}