From d41e018dcea5f12c61ab8c91e0838ab871de64e0 Mon Sep 17 00:00:00 2001
From: Thomas Segismont <tsegismont@gmail.com>
Date: Wed, 6 Nov 2024 11:48:42 +0100
Subject: [PATCH] Let subclasses invoke the protected VertxApplication
 constructor with a null hooks param. (#13)

Otherwise, a subclass cannot extend VertxApplicationHooks and control advanced parameters like exitOnFailure.

Signed-off-by: Thomas Segismont <tsegismont@gmail.com>
---
 .../application/VertxApplication.java         | 24 ++++++++++---------
 .../application/VertxApplicationHooks.java    |  3 +++
 .../CustomApplicationLowMemoryTest.java       |  2 +-
 3 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/application/src/main/java/io/vertx/launcher/application/VertxApplication.java b/application/src/main/java/io/vertx/launcher/application/VertxApplication.java
index a2256ff..204ed8c 100644
--- a/application/src/main/java/io/vertx/launcher/application/VertxApplication.java
+++ b/application/src/main/java/io/vertx/launcher/application/VertxApplication.java
@@ -50,15 +50,7 @@ public static void main(String[] args) {
    * @param args the program arguments
    */
   public VertxApplication(String[] args) {
-    this.args = Objects.requireNonNull(args);
-    if (this instanceof VertxApplicationHooks) {
-      hooks = (VertxApplicationHooks) this;
-    } else {
-      hooks = new VertxApplicationHooks() {
-      };
-    }
-    printUsageOnFailure = true;
-    exitOnFailure = true;
+    this(args, null);
   }
 
   /**
@@ -73,15 +65,25 @@ public VertxApplication(String[] args, VertxApplicationHooks hooks) {
 
   /**
    * May be invoked by subclasses to customize behavior.
+   * <p>
+   * When the {@code hooks} parameter is {@code null}, the application instance will be used if it implements {@link  VertxApplicationHooks}.
    *
    * @param args                the program arguments
-   * @param hooks               an instance of {@link VertxApplicationHooks} to be invoked at different stages of the launch process
+   * @param hooks               an instance of {@link VertxApplicationHooks} to be invoked at different stages of the launch process (maybe null)
    * @param printUsageOnFailure whether usage should be printed to {@link System#out} if the application failed to start
    * @param exitOnFailure       whether the JVM should be terminated with a specific {@code exitCode} if the application failed to start
    */
   protected VertxApplication(String[] args, VertxApplicationHooks hooks, boolean printUsageOnFailure, boolean exitOnFailure) {
     this.args = Objects.requireNonNull(args);
-    this.hooks = Objects.requireNonNull(hooks);
+    if (hooks == null) {
+      if (this instanceof VertxApplicationHooks) {
+        this.hooks = (VertxApplicationHooks) this;
+      } else {
+        this.hooks = VertxApplicationHooks.DEFAULT;
+      }
+    } else {
+      this.hooks = hooks;
+    }
     this.printUsageOnFailure = printUsageOnFailure;
     this.exitOnFailure = exitOnFailure;
   }
diff --git a/application/src/main/java/io/vertx/launcher/application/VertxApplicationHooks.java b/application/src/main/java/io/vertx/launcher/application/VertxApplicationHooks.java
index 75f1a15..a978b67 100644
--- a/application/src/main/java/io/vertx/launcher/application/VertxApplicationHooks.java
+++ b/application/src/main/java/io/vertx/launcher/application/VertxApplicationHooks.java
@@ -24,6 +24,9 @@
  */
 public interface VertxApplicationHooks {
 
+  VertxApplicationHooks DEFAULT = new VertxApplicationHooks() {
+  };
+
   /**
    * Invoked before starting Vert.x.
    * <p>
diff --git a/application/src/test/java/io/vertx/launcher/application/CustomApplicationLowMemoryTest.java b/application/src/test/java/io/vertx/launcher/application/CustomApplicationLowMemoryTest.java
index f9010ed..b05ac78 100644
--- a/application/src/test/java/io/vertx/launcher/application/CustomApplicationLowMemoryTest.java
+++ b/application/src/test/java/io/vertx/launcher/application/CustomApplicationLowMemoryTest.java
@@ -103,7 +103,7 @@ private boolean outputContainsMsgHook() {
   public static class MyVertxApplication extends VertxApplication implements VertxApplicationHooks {
 
     public MyVertxApplication(String[] args) {
-      super(args);
+      super(args, null, true, true);
     }
 
     public static void main(String[] args) {