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package org.graalvm.nativeimage;

Utility class to retrieve information about the context in which code gets executed. The provided string constants are part of the API and guaranteed to remain unchanged in future versions. This allows to use System.getProperty(String) directly with the string literals defined here thus eliminating the need to depend on this class. 
Since:
19.0/**
 * Utility class to retrieve information about the context in which code gets executed. The provided
 * string constants are part of the API and guaranteed to remain unchanged in future versions. This
 * allows to use {@link System#getProperty(String)} directly with the string literals defined here
 * thus eliminating the need to depend on this class.
 *
 * @since 19.0
 */
public final class ImageInfo {

    private ImageInfo() {
    }

    
Holds the string that is the name of the system property providing information about the context in which code is currently executing. If the property returns the string given by PROPERTY_IMAGE_CODE_VALUE_BUILDTIME the code is executing in the context of image building (e.g. in a static initializer of a class that will be contained in the image). If the property returns the string given by PROPERTY_IMAGE_CODE_VALUE_RUNTIME the code is executing at image runtime. Otherwise the property is not set. 
Since:
19.0/**
     * Holds the string that is the name of the system property providing information about the
     * context in which code is currently executing. If the property returns the string given by
     * {@link #PROPERTY_IMAGE_CODE_VALUE_BUILDTIME} the code is executing in the context of image
     * building (e.g. in a static initializer of a class that will be contained in the image). If
     * the property returns the string given by {@link #PROPERTY_IMAGE_CODE_VALUE_RUNTIME} the code
     * is executing at image runtime. Otherwise the property is not set.
     *
     * @since 19.0
     */
    public static final String PROPERTY_IMAGE_CODE_KEY = "org.graalvm.nativeimage.imagecode";

    
Holds the string that will be returned by the system property for PROPERTY_IMAGE_CODE_KEY if code is executing in the context of image building (e.g. in a static initializer of class that will be contained in the image). 
Since:
19.0/**
     * Holds the string that will be returned by the system property for
     * {@link ImageInfo#PROPERTY_IMAGE_CODE_KEY} if code is executing in the context of image
     * building (e.g. in a static initializer of class that will be contained in the image).
     *
     * @since 19.0
     */
    public static final String PROPERTY_IMAGE_CODE_VALUE_BUILDTIME = "buildtime";

    
Holds the string that will be returned by the system property for PROPERTY_IMAGE_CODE_KEY if code is executing at image runtime. 
Since:
19.0/**
     * Holds the string that will be returned by the system property for
     * {@link ImageInfo#PROPERTY_IMAGE_CODE_KEY} if code is executing at image runtime.
     *
     * @since 19.0
     */
    public static final String PROPERTY_IMAGE_CODE_VALUE_RUNTIME = "runtime";

    
Name of the system property that holds if this image is built as a shared library or an executable. If the property is PROPERTY_IMAGE_KIND_VALUE_EXECUTABLE the image is built as an executable. If the property is PROPERTY_IMAGE_KIND_VALUE_SHARED_LIBRARY the image is built as a shared library. 
Since:
19.0/**
     * Name of the system property that holds if this image is built as a shared library or an
     * executable. If the property is {@link #PROPERTY_IMAGE_KIND_VALUE_EXECUTABLE} the image is
     * built as an executable. If the property is {@link #PROPERTY_IMAGE_KIND_VALUE_SHARED_LIBRARY}
     * the image is built as a shared library.
     *
     * @since 19.0
     */
    public static final String PROPERTY_IMAGE_KIND_KEY = "org.graalvm.nativeimage.kind";

    
Holds the string that will be returned by the system property for PROPERTY_IMAGE_KIND_KEY if image is a shared library. 
Since:
19.0/**
     * Holds the string that will be returned by the system property for
     * {@link ImageInfo#PROPERTY_IMAGE_KIND_KEY} if image is a shared library.
     *
     * @since 19.0
     */
    public static final String PROPERTY_IMAGE_KIND_VALUE_SHARED_LIBRARY = "shared";

    
Holds the string that will be returned by the system property for PROPERTY_IMAGE_KIND_KEY if image is an executable. 
Since:
19.0/**
     * Holds the string that will be returned by the system property for
     * {@link ImageInfo#PROPERTY_IMAGE_KIND_KEY} if image is an executable.
     *
     * @since 19.0
     */
    public static final String PROPERTY_IMAGE_KIND_VALUE_EXECUTABLE = "executable";

    
Returns true if (at the time of the call) code is executing in the context of image building or during image runtime, else false. This method will be const-folded so that it can be used to hide parts of an application that only work when running on the JVM. For example: if (!ImageInfo.inImageCode()) { ... JVM specific code here ... } 
Since:
19.0/**
     * Returns true if (at the time of the call) code is executing in the context of image building
     * or during image runtime, else false. This method will be const-folded so that it can be used
     * to hide parts of an application that only work when running on the JVM. For example:
     * {@code if (!ImageInfo.inImageCode()) { ... JVM specific code here ... }}
     *
     * @since 19.0
     */
    public static boolean inImageCode() {
        return System.getProperty(PROPERTY_IMAGE_CODE_KEY) != null;
    }

    
Returns true if (at the time of the call) code is executing at image runtime. This method
will be const-folded. It can be used to hide parts of an application that only work when
running as native image.
Since:
19.0/**
     * Returns true if (at the time of the call) code is executing at image runtime. This method
     * will be const-folded. It can be used to hide parts of an application that only work when
     * running as native image.
     *
     * @since 19.0
     */
    public static boolean inImageRuntimeCode() {
        return PROPERTY_IMAGE_CODE_VALUE_RUNTIME.equals(System.getProperty(PROPERTY_IMAGE_CODE_KEY));
    }

    
Returns true if (at the time of the call) code is executing in the context of image building
(e.g. in a static initializer of class that will be contained in the image).
Since:
19.0/**
     * Returns true if (at the time of the call) code is executing in the context of image building
     * (e.g. in a static initializer of class that will be contained in the image).
     *
     * @since 19.0
     */
    public static boolean inImageBuildtimeCode() {
        return PROPERTY_IMAGE_CODE_VALUE_BUILDTIME.equals(System.getProperty(PROPERTY_IMAGE_CODE_KEY));
    }

    
Returns true if the image is build as an executable.
Since:
19.0/**
     * Returns true if the image is build as an executable.
     *
     * @since 19.0
     */
    public static boolean isExecutable() {
        ensureKindAvailable();
        return PROPERTY_IMAGE_KIND_VALUE_EXECUTABLE.equals(System.getProperty(PROPERTY_IMAGE_KIND_KEY));
    }

    
Returns true if the image is build as a shared library.
Since:
19.0/**
     * Returns true if the image is build as a shared library.
     *
     * @since 19.0
     */
    public static boolean isSharedLibrary() {
        ensureKindAvailable();
        return PROPERTY_IMAGE_KIND_VALUE_SHARED_LIBRARY.equals(System.getProperty(PROPERTY_IMAGE_KIND_KEY));
    }

    private static void ensureKindAvailable() {
        if (inImageCode() && System.getProperty(PROPERTY_IMAGE_KIND_KEY) == null) {
            throw new UnsupportedOperationException(
                            "The kind of image that is built (executable or shared library) is not available yet because the relevant command line option has not been parsed yet.");
        }
    }
}