nmode's Git Repositories - signal-cli/blob - src/main/java/org/asamk/signal/Shutdown.java

   1 package org.asamk.signal;
   2
   3 import org.slf4j.Logger;
   4 import org.slf4j.LoggerFactory;
   5
   6 import java.util.concurrent.CompletableFuture;
   7 import java.util.concurrent.ExecutionException;
   8
   9 import sun.misc.Signal;
  10
  11 public class Shutdown {
  12
  13     private static final Logger logger = LoggerFactory.getLogger(Shutdown.class);
  14     private static final CompletableFuture<Void> shutdown = new CompletableFuture<>();
  15     private static final CompletableFuture<Void> shutdownComplete = new CompletableFuture<>();
  16     private static boolean initialized = false;
  17
  18     public static void installHandler() {
  19         if (initialized) {
  20             return;
  21         }
  22         initialized = true;
  23         Signal.handle(new Signal("INT"), Shutdown::handleSignal);
  24         Signal.handle(new Signal("TERM"), Shutdown::handleSignal);
  25         Runtime.getRuntime().addShutdownHook(Thread.ofPlatform().unstarted(() -> {
  26             logger.debug("JVM is shutting down");
  27             if (!shutdown.isDone()) {
  28                 triggerShutdown();
  29             }
  30
  31             try {
  32                 logger.debug("Waiting for app to shut down");
  33                 shutdownComplete.get();
  34                 logger.debug("Exiting");
  35             } catch (InterruptedException | ExecutionException e) {
  36                 throw new RuntimeException(e);
  37             }
  38         }));
  39     }
  40
  41     public static void triggerShutdown() {
  42         logger.debug("Triggering shutdown.");
  43         shutdown.complete(null);
  44     }
  45
  46     public static void waitForShutdown() throws InterruptedException {
  47         try {
  48             shutdown.get();
  49         } catch (ExecutionException e) {
  50             throw new RuntimeException(e);
  51         }
  52     }
  53
  54     public static void registerShutdownListener(Runnable action) {
  55         shutdown.thenRun(action);
  56     }
  57
  58     static void shutdownComplete() {
  59         shutdownComplete.complete(null);
  60     }
  61
  62     private static void handleSignal(Signal signal) {
  63         logger.info("Received {} signal, shutting down ...", signal);
  64         triggerShutdown();
  65     }
  66 }