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General data-binding functionality for Jackson: works on core streaming API

There is a newer version: 2.18.1

package com.fasterxml.jackson.databind.util;

import java.lang.reflect.InvocationTargetException;

/**
 * Utilities for graal native image support; mostly to improve error message handling
 * in case of missing information for native image.
 *
 * @since 2.14
 */
public class NativeImageUtil {
    
    private static final boolean RUNNING_IN_SVM = System.getProperty("org.graalvm.nativeimage.imagecode") != null;

    private NativeImageUtil() { }

    /**
     * Check whether we're running in SubstrateVM native image and also in "runtime" mode.
     * The "runtime" check cannot be a constant, because
     * the static initializer may run early during build time
     *
     * As optimization, {@code RUNNING_IN_SVM} is used to short-circuit on normal JVMs.
     *
     * @since 2.16
     */
    public static boolean isInNativeImageAndIsAtRuntime() {
        return RUNNING_IN_SVM && "runtime".equals(System.getProperty("org.graalvm.nativeimage.imagecode"));
    }

    /**
     * Checks whether we're running in SubstrateVM native image only by the presence of 
     * {@code "org.graalvm.nativeimage.imagecode"} system property, regardless of its value (buildtime or runtime).
     * We are irrespective of the build or runtime phase, because native-image can initialize static initializers at build time.
     *
     * @since 2.16
     */
    public static boolean isInNativeImage() {
        return RUNNING_IN_SVM;
    }

    /**
     * Check whether the given error is a substratevm UnsupportedFeatureError
     */
    public static boolean isUnsupportedFeatureError(Throwable e) {
        if (!isInNativeImageAndIsAtRuntime()) {
            return false;
        }
        if (e instanceof InvocationTargetException) {
            e = e.getCause();
        }
        return e.getClass().getName().equals("com.oracle.svm.core.jdk.UnsupportedFeatureError");
    }

    /**
     * Check whether the given class is likely missing reflection configuration (running in native image, and no
     * members visible in reflection).
     */
    public static boolean needsReflectionConfiguration(Class cl) {
        if (!isInNativeImageAndIsAtRuntime()) {
            return false;
        }
        // records list their fields but not other members
        return (cl.getDeclaredFields().length == 0 || ClassUtil.isRecordType(cl)) &&
                cl.getDeclaredMethods().length == 0 &&
                cl.getDeclaredConstructors().length == 0;
    }
}