org.graalvm.nativeimage.LogHandler Maven / Gradle / Ivy
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package org.graalvm.nativeimage;
import org.graalvm.nativeimage.c.type.CCharPointer;
import org.graalvm.word.UnsignedWord;
/**
* Low-level handler for log messages of native images. Implement this interface to create a custom
* log handler, i.e., redirect log messages. The custom log handler must be installed in the
* {@code ImageSingletons}, using this interface as the key, at {@code Feature.duringSetup()} time:
*
*
* class LogHandlerFeature implements Feature {
* {@literal @}Override
* public void duringSetup(DuringSetupAccess access) {
* ImageSingletons.add(LogHandler.class, new CustomLogHandler());
* }
* }
*
*
* If no custom log handler is installed, a default is installed
* {@code Feature.beforeAnalysis() before the static analysis}. The default handler prints log
* messages to the standard output. Installing a custom log handler at a later time, after the
* default one has been installed, results in an error.
*
* The methods defined in this interface are called from places where Java object allocation is not
* possible, e.g., during a garbage collection or before the heap is set up. If an implementation of
* the interface allocates a Java object or array, an error is reported during image generation.
*
* @since 19.0
*/
public interface LogHandler {
/**
* Write raw bytes to the log.
*
* The methods defined in this interface are called from places where Java object allocation is
* not possible, e.g., during a garbage collection or before the heap is set up. If an
* implementation of the interface allocates a Java object or array, an error is reported during
* image generation.
*
* @since 19.0
*/
void log(CCharPointer bytes, UnsignedWord length);
/**
* Flush the log to its destination.
*
* The methods defined in this interface are called from places where Java object allocation is
* not possible, e.g., during a garbage collection or before the heap is set up. If an
* implementation of the interface allocates a Java object or array, an error is reported during
* image generation.
*
* @since 19.0
*/
void flush();
/**
* Exit the VM because a fatal, non-recoverable error situation has been detected. The
* implementation of this method must not return, and it must not throw a Java exception. A
* valid implementation is, e.g., to ask the OS to kill the process.
*
* The methods defined in this interface are called from places where Java object allocation is
* not possible, e.g., during a garbage collection or before the heap is set up. If an
* implementation of the interface allocates a Java object or array, an error is reported during
* image generation.
*
* @since 19.0
*/
void fatalError();
}