jooby-run: improve restart process (less memory/fast)

- queue the compilation process
- fix  #3482

Author: jknack

modules/jooby-gradle-plugin/src/main/java/io/jooby/gradle/RunTask.java

@@ -13,6 +13,8 @@
 import java.util.Optional;
 import java.util.Scanner;
 import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
 
@@ -112,20 +114,32 @@ public void run() throws Throwable {
 
       BiConsumer<String, Path> onFileChanged = (event, path) -> {
         if (config.isCompileExtension(path)) {
-          BuildLauncher compiler = connection.newBuild()
-              .setStandardError(System.err)
-              .setStandardOutput(System.out)
-              .forTasks(taskList.toArray(new String[0]));
-
-          compiler.run(new ResultHandler<Void>() {
-            @Override public void onComplete(Void result) {
-              getLogger().debug("Restarting application on file change: " + path);
-              joobyRun.restart(path);
-            }
-
-            @Override public void onFailure(GradleConnectionException failure) {
-              getLogger().debug("Compilation error found: " + path);
-            }
+          joobyRun.restart(path, () -> {
+            CountDownLatch latch = new CountDownLatch(1);
+            AtomicBoolean success = new AtomicBoolean(false);
+            BuildLauncher compiler = connection.newBuild()
+                    .setStandardError(System.err)
+                    .setStandardOutput(System.out)
+                    .forTasks(taskList.toArray(new String[0]));
+
+            compiler.run(new ResultHandler<Void>() {
+              @Override public void onComplete(Void result) {
+                getLogger().debug("Restarting application on file change: " + path);
+                success.set(true);
+                latch.countDown();
+              }
+
+              @Override public void onFailure(GradleConnectionException failure) {
+                getLogger().debug("Compilation error found: " + path);
+                latch.countDown();
+              }
+            });
+              try {
+                  latch.await();
+              } catch (InterruptedException e) {
+                  Thread.currentThread().interrupt();
+              }
+              return success.get();
           });
         } else if (config.isRestartExtension(path)) {
           getLogger().debug("Restarting application on file change: " + path);

modules/jooby-maven-plugin/src/main/java/io/jooby/maven/RunMojo.java

@@ -89,16 +89,21 @@ protected void doExecute(List<MavenProject> projects, String mainClass) throws T
     BiConsumer<String, Path> onFileChanged =
         (event, path) -> {
           if (options.isCompileExtension(path)) {
-            MavenExecutionResult result = maven.execute(mavenRequest("process-classes"));
-            // Success?
-            if (result.hasExceptions()) {
-              getLog().debug("Compilation error found: " + path);
-            } else {
-              getLog().debug("Restarting application on file change: " + path);
-              joobyRun.restart(path);
-            }
+            getLog().debug("Restarting application on file change: " + path);
+            joobyRun.restart(
+                path,
+                () -> {
+                  MavenExecutionResult result = maven.execute(mavenRequest("process-classes"));
+                  var error = result.hasExceptions();
+                  // Success?
+                  if (error) {
+                    getLog().debug("Compilation error found: " + path);
+                  }
+                  return !error;
+                });
           } else if (options.isRestartExtension(path)) {
             getLog().debug("Restarting application on file change: " + path);
+            // No compilation required, returns true to proceed with restart
             joobyRun.restart(path);
           } else {
             getLog().debug("Ignoring file change: " + path);

modules/jooby-run/src/main/java/io/jooby/run/JoobyRun.java

@@ -13,18 +13,14 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.time.Clock;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.LinkedHashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
+import java.util.*;
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.BiConsumer;
+import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -52,7 +48,7 @@
  */
 public class JoobyRun {
 
-  private record Event(Path path, long time) {}
+  private record Event(Path path, long time, Supplier<Boolean> compileTask) {}
 
   private static class AppModule {
     private final Logger logger;
@@ -420,7 +416,11 @@ public void start() throws Throwable {
 
   /** Restart the application. */
   public void restart(Path path) {
-    queue.offer(new Event(path, clock.millis()));
+    restart(path, null);
+  }
+
+  public void restart(Path path, Supplier<Boolean> compileTask) {
+    queue.offer(new Event(path, clock.millis(), compileTask));
   }
 
   private synchronized void actualRestart() {
@@ -433,13 +433,21 @@ private synchronized void actualRestart() {
       return; // queue was empty
     }
     var unload = false;
+    Supplier<Boolean> compileTask = null;
     for (; e != null && (t - e.time) > waitTimeBeforeRestartMillis; e = queue.peek()) {
       unload = unload || options.isCompileExtension(e.path);
+      compileTask = Optional.ofNullable(compileTask).orElse(e.compileTask);
       queue.poll();
     }
     // e will be null if the queue is empty which means all events were old enough
     if (e == null) {
-      module.restart(unload);
+      var restart = true;
+      if (compileTask != null) {
+        restart = compileTask.get();
+      }
+      if (restart) {
+        module.restart(unload);
+      }
     }
   }