Package org.jline.utils

Class Signals

java.lang.Object

org.jline.utils.Signals

public final class Signals
extends Object

Signal handling utilities for terminal applications.

The Signals class provides utilities for registering and handling system signals in a platform-independent way. It allows terminal applications to respond to signals such as SIGINT (Ctrl+C), SIGTSTP (Ctrl+Z), and others, without having to use platform-specific code.

This class uses reflection to access the underlying signal handling mechanisms of the JVM, which may vary depending on the platform and JVM implementation. It provides a consistent API for signal handling across different environments.

Signal handling is particularly important for terminal applications that need to respond to user interrupts or that need to perform cleanup operations when the application is terminated.

Since:

3.0

Method Summary

Modifier and Type	Method	Description
static Object	register(String name, Runnable handler)	Registers a handler for the specified signal.
static Object	register(String name, Runnable handler, ClassLoader loader)
static Object	registerDefault(String name)
static void	unregister(String name, Object previous)

Methods inherited from class java.lang.Object

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

Method Details

register

public static Object register(String name,
 Runnable handler)

Registers a handler for the specified signal.

This method registers a handler for the specified signal. The handler will be called when the signal is received. The method returns an object that can be used to unregister the handler later.

Signal names are platform-dependent, but common signals include:

• INT - Interrupt signal (typically Ctrl+C)
• TERM - Termination signal
• HUP - Hangup signal
• CONT - Continue signal
• STOP - Stop signal (typically Ctrl+Z)
• WINCH - Window change signal

Example usage:

 Object handle = Signals.register("INT", () -> {
     System.out.println("Caught SIGINT");
     // Perform cleanup
 });

 // Later, when no longer needed
 Signals.unregister("INT", handle);
 

Parameters:

name - the signal name (e.g., "INT", "TERM", "HUP")

handler - the callback to run when the signal is received

Returns:

an object that can be used to unregister the handler

See Also:

• method to unregister the handler

register

public static Object register(String name,
 Runnable handler,
 ClassLoader loader)

registerDefault

public static Object registerDefault(String name)

unregister

public static void unregister(String name,
 Object previous)