Verticle api improvements

src/main/java/io/vertx/core/VerticleBase.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2011-2023 Contributors to the Eclipse Foundation
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+ * which is available at https://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+ */
+
+package io.vertx.core;
+
+/**
+ *
+ * An abstract base class that you can extend to write your own Verticle classes.
+ * <p>
+ * Instead of implementing {@link Verticle} directly, it is often simpler to just extend this class.
+ * <p>
+ * In the simplest case, just override the {@link #start()} method. If you have verticle clean-up to do you can optionally
+ * override the {@link #stop()} method too.
+ * <p>
+ * This class also maintains references to the {@link Vertx} and {@link Context} instances of the verticle for easy access.<p>
+ *
+ * @author <a href="http://tfox.org">Tim Fox</a>
+ * @author <a href="mailto:julien@julienviet.com">Julien Viet</a>
+ */
+public abstract class VerticleBase implements Verticle {
+
+  /**
+   * Reference to the Vert.x instance that deployed this verticle
+   */
+  protected Vertx vertx;
+
+  /**
+   * Reference to the context of the verticle
+   */
+  protected Context context;
+
+  /**
+   * Get the Vert.x instance
+   * @return the Vert.x instance
+   */
+  @Override
+  public final Vertx getVertx() {
+    return vertx;
+  }
+
+  /**
+   * Initialise the verticle.<p>
+   * This is called by Vert.x when the verticle instance is deployed. Don't call it yourself.
+   * @param vertx  the deploying Vert.x instance
+   * @param context  the context of the verticle
+   */
+  @Override
+  public final void init(Vertx vertx, Context context) {
+    this.vertx = vertx;
+    this.context = context;
+  }
+
+  /**
+   * This is called by Vert.x when the verticle instance is undeployed. Don't call it yourself.
+   */
+  @Override
+  @SuppressWarnings("unchecked")
+  public final void start(Promise<Void> startPromise) throws Exception {
+    handle(start(), startPromise);
+  }
+
+  /**
+   * This is called by Vert.x when the verticle instance is deployed. Don't call it yourself.<p>
+   */
+  @Override
+  public final void stop(Promise<Void> stopPromise) throws Exception {
+    handle(stop(), stopPromise);
+  }
+
+  private void handle(Future<?> completion, Promise<Void> promise) {
+    if (completion != null) {
+      completion.onComplete((Handler) promise);
+    } else {
+      promise.complete();
+    }
+  }
+
+  /**
+   * Override to implement Verticle start.
+   *
+   * @throws Exception any exception preventing the start of the verticle
+   */
+  public Future<?> start() throws Exception {
+    return Future.succeededFuture();
+  }
+
+  /**
+   * Override this put your clean-up code in here.
+   *
+   * @throws Exception any exception happening during the stop of the verticle
+   */
+  public Future<?> stop() throws Exception {
+    return Future.succeededFuture();
+  }
+}