picocli.codegen.aot.graalvm

Class ReflectionConfigGenerator

java.lang.Object

picocli.codegen.aot.graalvm.ReflectionConfigGenerator

public class ReflectionConfigGenerator
extends java.lang.Object

ReflectionConfigGenerator generates a JSON String with the program elements that will be accessed reflectively in a picocli-based application, in order to compile this application ahead-of-time into a native executable with GraalVM.

GraalVM has limited support for Java reflection and it needs to know ahead of time the reflectively accessed program elements.

The output of ReflectionConfigGenerator is intended to be passed to the -H:ReflectionConfigurationFiles=/path/to/reflect-config.json option of the native-image GraalVM utility. This allows picocli-based applications to be compiled to a native image.

Alternatively, the generated configuration files can be supplied to the native-image tool by placing them in a META-INF/native-image/ directory on the class path, for example, in a JAR file used in the image build. This directory (or any of its subdirectories) is searched for files with the names jni-config.json, reflect-config.json, proxy-config.json and resource-config.json, which are then automatically included in the build. Not all of those files must be present. When multiple files with the same name are found, all of them are included.

If necessary, it is possible to exclude classes with system property picocli.codegen.excludes, which accepts a comma-separated list of regular expressions of the fully qualified class names that should not be included in the resulting JSON String.

Since:

3.7.0

Constructor Summary

Constructors

Constructor and Description
ReflectionConfigGenerator()

Method Summary

Modifier and Type	Method and Description
static java.lang.String	generateReflectionConfig(picocli.CommandLine.Model.CommandSpec... specs) Returns a JSON String with the program elements that will be accessed reflectively for the specified CommandSpec objects.
static void	main(java.lang.String... args) Runs this class as a standalone application, printing the resulting JSON String to a file or to System.out.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ReflectionConfigGenerator

public ReflectionConfigGenerator()

Method Detail

main

public static void main(java.lang.String... args)

Runs this class as a standalone application, printing the resulting JSON String to a file or to System.out.

Parameters:

args - one or more fully qualified class names of @Command-annotated classes.

generateReflectionConfig

public static java.lang.String generateReflectionConfig(picocli.CommandLine.Model.CommandSpec... specs)
                                                 throws java.lang.Exception

Returns a JSON String with the program elements that will be accessed reflectively for the specified CommandSpec objects.

Parameters:

specs - one or more CommandSpec objects to inspect

Returns:

a JSON String in the format required by the -H:ReflectionConfigurationFiles=/path/to/reflect-config.json option of the GraalVM native-image utility.

Throws:

java.lang.NoSuchFieldException - if a problem occurs while processing the specified specs

java.lang.IllegalAccessException - if a problem occurs while processing the specified specs

java.lang.Exception