Package org.jline.utils

Class ShutdownHooks

java.lang.Object

org.jline.utils.ShutdownHooks

public final class ShutdownHooks
extends Object

Manages the JLine shutdown-hook thread and tasks to execute on shutdown.

The ShutdownHooks class provides a centralized mechanism for registering tasks that should be executed when the JVM shuts down. It manages a single shutdown hook thread that executes all registered tasks in the reverse order of their registration.

This class is particularly useful for terminal applications that need to perform cleanup operations when the application is terminated, such as restoring the terminal to its original state, closing open files, or releasing other resources.

Tasks are registered using the add(Task) method and can be removed using the remove(Task) method. All tasks must implement the ShutdownHooks.Task interface, which defines a single ShutdownHooks.Task.run() method that is called when the JVM shuts down.

Example usage:

 // Create a task to restore the terminal on shutdown
 ShutdownHooks.Task task = ShutdownHooks.add(() -> {
     terminal.setAttributes(originalAttributes);
     terminal.close();
 });

 // Later, if the task is no longer needed
 ShutdownHooks.remove(task);
 

Since:

2.7

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	ShutdownHooks.Task	Essentially a Runnable which allows running to throw an exception.

Constructor Summary

Constructors

Constructor	Description
ShutdownHooks()

Method Summary

Modifier and Type	Method	Description
static <T extends ShutdownHooks.Task> T	add(T task)	Adds a task to be executed when the JVM shuts down.
static void	remove(ShutdownHooks.Task task)

Methods inherited from class java.lang.Object

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

Constructor Details

ShutdownHooks

public ShutdownHooks()

Method Details

add

public static <T extends ShutdownHooks.Task> T add(T task)

Adds a task to be executed when the JVM shuts down.

This method registers a task to be executed when the JVM shuts down. Tasks are executed in the reverse order of their registration, so the most recently added task will be executed first.

If this is the first task to be added, a shutdown hook thread will be created and registered with the JVM. This thread will execute all registered tasks when the JVM shuts down.

Type Parameters:

T - the type of the task

Parameters:

task - the task to be executed on shutdown

Returns:

the task that was added (for method chaining)

Throws:

NullPointerException - if the task is null

remove

public static void remove(ShutdownHooks.Task task)